Archived NIST Technical Series Publication 

The attached publication has been archived (withdrawn), and is provided solely for historical purposes. 

It may have been superseded by another publication (indicated below). 

Archived Publication 

Series/Number: 

Title: 

Publication Date(s): 

Withdrawal Date: 

Withdrawal Note: 

Superseding Publication(s) 

The attached publication has been superseded by the following publication(s): 

Series/Number: 

Title: 

Author(s): 

Publication Date(s): 

URL/DOI: 

Additional Information (if applicable) 

Contact:

Latest revision of the 

attached publication: 

Related information: 

Withdrawal 

announcement (link): 

Date updated: ƵŐƵƐƚϭϮ, 2015 

NIST Special Publication 800-121

Guide to Bluetooth Security

September 2008

June 2012

SP 800-121 is superseded in its entirety by the publication of

SP 800-121 Revision 1 (June 2012).

NIST Special Publication 800-121 Revision 1

Guide to Bluetooth Security

Quynh Dang

June 2012

http://dx.doi.org/10.6028/NIST.SP.121r1

Computer Security Division (Information Technology Lab)

SP 800-121 Revision 1 (as of August 12, 2015)

http://csrc.nist.gov/

N/A
Special Publication 800-121

Guide to Bluetooth Security 

Recommendations of the National Institute of 

Standards and Technology 

Karen Scarfone 

John Padgette 
Guide to Bluetooth Security 

Recommendations of the National 

Institute of Standards and Technology 

Karen Scarfone 

John Padgette 

NIST Special Publication 800-121 

C O M P U T E R S E C U R I T Y

DRAFT 

Computer Security Division 

Information Technology Laboratory 

National Institute of Standards and Technology 

Gaithersburg, MD 20899-8930 

September 2008

U.S. Department of Commerce 

Carlos M. Gutierrez, Secretary 

National Institute of Standards and Technology

Dr. Patrick D. Gallagher, Deputy Director 
GUIDE TO BLUETOOTH SECURITY

Reports on Computer Systems Technology 

The Information Technology Laboratory (ITL) at the National Institute of Standards and Technology 

(NIST) promotes the U.S. economy and public welfare by providing technical leadership for the nation’s 

measurement and standards infrastructure. ITL develops tests, test methods, reference data, proof of 

concept implementations, and technical analysis to advance the development and productive use of 

information technology. ITL’s responsibilities include the development of technical, physical, 

administrative, and management standards and guidelines for the cost-effective security and privacy of 

sensitive unclassified information in Federal computer systems. This Special Publication 800-series 

reports on ITL’s research, guidance, and outreach efforts in computer security and its collaborative 

activities with industry, government, and academic organizations. 

Certain commercial entities, equipment, or materials may be identified in this 

document in order to describe an experimental procedure or concept adequately. 

Such identification is not intended to imply recommendation or endorsement by the 

National Institute of Standards and Technology, nor is it intended to imply that the 

entities, materials, or equipment are necessarily the best available for the purpose. 

National Institute of Standards and Technology Special Publication 800-121 

Natl. Inst. Stand. Technol. Spec. Publ. 800-121, 43 pages (Sep. 2008) 

ii 
GUIDE TO BLUETOOTH SECURITY

Acknowledgments 

The authors, Karen Scarfone of the National Institute of Standards and Technology (NIST) and John 

Padgette of Booz Allen Hamilton, wish to thank their colleagues who reviewed drafts of this document 

and contributed to its technical content. The authors would like to acknowledge Sheila Frankel, Tim 

Grance, and Tom Karygiannis of NIST, and Derrick Dicoi, Matthew Sexton, and Michael Bang of Booz 

Allen Hamilton, for their keen and insightful assistance throughout the development of the document. 

The authors also greatly appreciate the feedback provided by representatives from the Department of 

State, Gerry Barsczewski (Social Security Administration), Alex Froede (Defense Information Systems 

Agency [DISA]), and Dave Wallace and Mark Nichols (Spanalytics). 

Note to Readers 

This document was originally released for public comment as part of Draft NIST Special Publication (SP) 

800-48 Revision 1, Wireless Network Security for IEEE 802.11a/b/g and Bluetooth, which also provides 

information on securing legacy wireless local area networks (WLAN) unable to comply with the IEEE 

802.11i security standard. Based on reviewer feedback, the Bluetooth material was removed from SP 

800-48 Revision 1 and placed in this publication instead. Readers seeking information on WLAN 

security should consult the final version of SP 800-48 Revision 1, Guide to Securing Legacy IEEE 802.11 

Wireless Networks for legacy WLANs and SP 800-97, Establishing Wireless Robust Security Networks: A 

Guide to IEEE 802.11i for current WLANs. 

iii 
GUIDE TO BLUETOOTH SECURITY

Table of Contents 

Executive Summary..............................................................................................................ES-1

1. Introduction ......................................................................................................................1-1

1.1 Authority...................................................................................................................1-1

1.2 Purpose and Scope .................................................................................................1-1

1.3 Audience and Assumptions .....................................................................................1-1

1.4 Document Organization ...........................................................................................1-2

2. Overview of Bluetooth Technology................................................................................2-1

2.1 Bluetooth Technology Characteristics .....................................................................2-1

2.2 Bluetooth Architecture..............................................................................................2-3

3. Bluetooth Security Features ...........................................................................................3-1

3.1 Security Features of Bluetooth Specifications .........................................................3-2

3.2 Link Key Generation ................................................................................................3-2

3.2.1 Security Modes 2 and 3................................................................................3-3

3.2.2 Security Mode 4............................................................................................3-4

3.3 Authentication ..........................................................................................................3-5

3.4 Confidentiality ..........................................................................................................3-7

3.5 Trust Levels, Service Levels, and Authorization ......................................................3-9

4. Bluetooth Vulnerabilities, Threats, and Countermeasures..........................................4-1

4.1 Bluetooth Vulnerabilities ..........................................................................................4-1

4.2 Bluetooth Threats.....................................................................................................4-2

4.3 Risk Mitigation and Countermeasures .....................................................................4-3

4.4 Bluetooth Security Checklists ..................................................................................4-4

List of Appendices 

Appendix A— Glossary of Terms.......................................................................................... A-1

Appendix B— Acronyms and Abbreviations ....................................................................... B-1

Appendix C— References ...................................................................................................... C-1

Appendix D— Online Resources........................................................................................... D-1

iv 
GUIDE TO BLUETOOTH SECURITY

List of Figures 

Figure 2-1. Bluetooth Ad Hoc Topology....................................................................................2-3

Figure 2-2. Bluetooth Networks (Multiple Scatternets) .............................................................2-4

Figure 3-1. Bluetooth Air-Interface Security..............................................................................3-1

Figure 3-2. Link Key Generation from PIN (v2.0 & earlier) .......................................................3-3

Figure 3-3. Link Key Establishment for Secure Simple Pairing ................................................3-5

Figure 3-4. Bluetooth Authentication.........................................................................................3-6

Figure 3-5. Bluetooth Encryption Procedure.............................................................................3-8

List of Tables 

Table 2-1. Bluetooth Device Classes of Power Management...................................................2-2

Table 4-1. Key Problems with Existing (Native) Bluetooth Security..........................................4-1

Table 4-2. Bluetooth Piconet Security Checklist .......................................................................4-5

Table 4-3. Bluetooth Headset Security Checklist....................................................................4-10

Table 4-4. Bluetooth Smart Card Reader Security Checklist..................................................4-12

v 
GUIDE TO BLUETOOTH SECURITY

Executive Summary 

Bluetooth is an open standard for short-range radio frequency (RF) communication. Bluetooth 

technology is used primarily to establish wireless personal area networks (WPAN), commonly referred to 

as ad hoc or peer-to-peer (P2P) networks. Bluetooth technology has been integrated into many types of 

business and consumer devices, including cellular phones, personal digital assistants (PDA), laptops, 

automobiles, printers, and headsets. This allows users to form ad hoc networks between a wide variety of 

devices to transfer voice and data. This document provides an overview of Bluetooth technology and 

discusses related security concerns. 

There have been several versions of Bluetooth, with the most recent being 2.0 + Enhanced Data Rate 

(EDR) (November 2004) and 2.1 + EDR (July 2007). While 2.0 + EDR provided faster transmission 

speeds than previous versions (up to 3 Mbits/second), 2.1 + EDR provides a significant security 

improvement for link key generation and management in the form of Secure Simple Pairing (SSP). This 

publication addresses the security of these versions of Bluetooth, as well as the earlier versions 1.1 and 

1.2. 

Bluetooth technology and associated devices are susceptible to general wireless networking threats, such 

as denial of service attacks, eavesdropping, man-in-the-middle attacks, message modification, and 

resource misappropriation. They are also threatened by more specific Bluetooth-related attacks that target 

known vulnerabilities in Bluetooth implementations and specifications. Attacks against improperly 

secured Bluetooth implementations can provide attackers with unauthorized access to sensitive 

information and unauthorized usage of Bluetooth devices and other systems or networks to which the 

devices are connected. 

To improve the security of Bluetooth implementations, organizations should implement the following 

recommendations: 

Organizations should use the strongest Bluetooth security mode available for their Bluetooth 

devices. 

The Bluetooth specifications define four security modes, and each version of Bluetooth supports some, 

but not all, of these modes. The modes vary primarily by how well they protect Bluetooth 

communications from potential attack. Security Mode 3 is considered the strongest mode because it 

requires authentication and encryption to be established before the Bluetooth physical link is completely 

established. Security Modes 2 and 4 also use authentication and encryption, but only after the Bluetooth 

physical link has already been fully established and logical channels partially established. Security Mode 

1 provides no security functionality. The available modes vary based on the Bluetooth specification 

versions of both devices, so organizations should choose the most secure mode available for each case. 

Organizations using Bluetooth technology should address Bluetooth technology in their security 

policies and change default settings of Bluetooth devices to reflect the policies. 

A security policy that defines requirements for Bluetooth security is the foundation for all other 

Bluetooth-related countermeasures. The policy should include a list of approved uses for Bluetooth, a list 

of the types of information that may be transferred over Bluetooth networks, and requirements for 

selecting and using Bluetooth personal identification numbers (PIN). After establishing Bluetooth 

security policy, organizations should ensure that Bluetooth devices’ default settings are reviewed and 

changed as needed so that they comply with the security policy requirements. For example, a typical 

requirement is that unneeded Bluetooth profiles and services be disabled to reduce the number of 

ES-1 
GUIDE TO BLUETOOTH SECURITY

vulnerabilities that attackers could attempt to exploit. When available, a centralized security policy 

management approach should be used to ensure device configurations are compliant. 

Organizations should ensure that their Bluetooth users are made aware of their security-related 

responsibilities regarding Bluetooth use. 

A security awareness program helps users to follow security practices that help prevent security incidents. 

For example, users should be provided with a list of precautionary measures they should take to better 

protect handheld Bluetooth devices from theft. Users should also be made aware of other actions to take 

involving Bluetooth device security, such as ensuring that Bluetooth devices are turned off when they are 

not needed to minimize exposure to malicious activities, and performing Bluetooth device pairing as 

infrequently as possible and ideally in a physically secure area where attackers cannot observe key entry 

and eavesdrop on Bluetooth pairing-related communications. 

ES-2 
GUIDE TO BLUETOOTH SECURITY

1. Introduction 

1.1 Authority 

The National Institute of Standards and Technology (NIST) developed this document in furtherance of its 

statutory responsibilities under the Federal Information Security Management Act (FISMA) of 2002, 

Public Law 107-347. 

NIST is responsible for developing standards and guidelines, including minimum requirements, for 

providing adequate information security for all agency operations and assets; however, such standards and 

guidelines shall not apply to national security systems. This guideline is consistent with the requirements 

of the Office of Management and Budget (OMB) Circular A-130, Section 8b (3), “Securing Agency 

Information Systems,” as analyzed in A-130, Appendix IV: Analysis of Key Sections. Supplemental 

information is provided in A-130, Appendix III. 

This guideline has been prepared for use by Federal agencies. It may be used by nongovernmental 

organizations on a voluntary basis and is not subject to copyright, although attribution is desired. 

Nothing in this document should be taken to contradict standards and guidelines made mandatory and 

binding on Federal agencies by the Secretary of Commerce under statutory authority, nor should these 

guidelines be interpreted as altering or superseding the existing authorities of the Secretary of Commerce, 

Director of the OMB, or any other Federal official. 

1.2 Purpose and Scope 

The purpose of this document is to provide information to organizations on the security capabilities of 

Bluetooth and provide recommendations to organizations employing Bluetooth technologies on securing 

them effectively. 

1.3 Audience and Assumptions 

This document discusses Bluetooth technologies and security capabilities in technical detail. This 

document assumes that the readers have at least some operating system, wireless networking, and security 

knowledge. Because of the constantly changing nature of the wireless security industry and the threats 

and vulnerabilities to the technologies, readers are strongly encouraged to take advantage of other 

resources (including those listed in this document) for more current and detailed information. 

The following list highlights people with differing roles and responsibilities that might use this document: 

 Government managers (e.g., chief information officers and senior managers) who oversee the use and 

security of Bluetooth technologies within their organizations 

 Systems engineers and architects who design and implement Bluetooth technologies 

 Auditors, security consultants, and others who perform security assessments of wireless environments 

 Researchers and analysts who are trying to understand the underlying wireless technologies. 

1-1 
GUIDE TO BLUETOOTH SECURITY

1.4 Document Organization 

The remainder of this document is composed of the following sections and appendices: 

 Section 2 provides an overview of Bluetooth technology, including its benefits, technical 

characteristics, and architecture. 

 Section 3 discusses the security features defined in the Bluetooth specifications and highlights their 

limitations. 

 Section 4 examines common vulnerabilities and threats involving Bluetooth technologies and makes 

recommendations for countermeasures to improve Bluetooth security. 

 Appendix A provides a glossary of terms. 

 Appendix B provides a list of acronyms and abbreviations used in this document. 

 Appendix C lists Bluetooth references. 

 Appendix D lists Bluetooth online resources.

1-2 
GUIDE TO BLUETOOTH SECURITY

2. Overview of Bluetooth Technology 

Bluetooth is an open standard for short-range radio frequency (RF) communication. Bluetooth 

technology is used primarily to establish wireless personal area networks (WPAN), commonly referred to 

as ad hoc or peer-to-peer (P2P) networks. Bluetooth technology has been integrated into many types of 

business and consumer devices, including cellular phones, personal digital assistants (PDA), laptops, 

automobiles, printers, and headsets. This allows users to form ad hoc networks between a wide variety of 

devices to transfer voice and data. Bluetooth is a low-cost, low-power technology that provides a 

mechanism for creating small wireless networks on an ad hoc basis, known as piconets.

1

 A piconet is 

composed of two or more Bluetooth devices in close physical proximity that operate on the same channel 

using the same frequency hopping sequence. An example of a piconet is a Bluetooth-based connection 

between a cellular phone and a Bluetooth-enabled ear bud. 

Bluetooth piconets are often established on a temporary and changing basis, which offers communication 

flexibility and scalability between mobile devices. Some key benefits of Bluetooth technology are: 

 Cable replacement. Bluetooth technology replaces a variety of cables, such as those traditionally 

used for peripheral devices (e.g., mouse and keyboard connections), printers, and wireless headsets 

and ear buds that interface with personal computers (PC) or mobile telephones. 

 Ease of file sharing. A Bluetooth-enabled device can form a piconet to support file sharing 

capabilities with other Bluetooth devices, such as laptops. 

 Wireless synchronization. Bluetooth provides automatic synchronization between Bluetoothenabled devices. For example, Bluetooth allows synchronization of contact information contained in 

electronic address books and calendars. 

 Internet connectivity. A Bluetooth device with Internet connectivity can share that access with other 

Bluetooth devices. For example, a laptop can use a Bluetooth connection to have a mobile phone 

establish a dial-up connection, so that the laptop can access the Internet through the phone. 

Bluetooth technology was originally conceived by Ericsson in 1994. Ericsson, IBM, Intel, Nokia, and 

Toshiba formed the Bluetooth Special Interest Group (SIG), a not-for-profit trade association developed 

to drive the development of Bluetooth products and serve as the governing body for Bluetooth 

specifications.2

 Bluetooth is standardized within the IEEE 802.15 Working Group for Wireless Personal 

Area Networks that formed in early 1999 as IEEE 802.15.1-2002.3

 

This section provides an overview of Bluetooth technology, such as frequency and data rates, range, and 

architecture. 

2.1 Bluetooth Technology Characteristics 

Bluetooth operates in the unlicensed 2.4 gigahertz (GHz) to 2.4835 GHz Industrial, Scientific, and 

Medical (ISM) frequency band. Numerous technologies operate in this band, including the IEEE 

802.11b/g WLAN standard, making it somewhat crowded from the standpoint of the volume of wireless 

transmissions. Bluetooth employs frequency hopping spread spectrum (FHSS) technology for all 

transmissions. FHSS reduces interference and transmission errors and provides a limited level of 

transmission security. With FHSS technology, communications between Bluetooth devices use 79 

 

1

 As discussed in Section 2.2, the term “piconet” applies to both ad hoc and infrastructure Bluetooth networks. 2

 The Bluetooth SIG web site (http://www.bluetooth.com/) is a resource for Bluetooth-related information and provides 

numerous links to other sources of information. 3

 For more information, see the IEEE web site at http://grouper.ieee.org/groups/802/15/. 

2-1 
GUIDE TO BLUETOOTH SECURITY

different radio channels by hopping (i.e., changing) frequencies about 1600 times per second for 

data/voice links and 3200 times per second during page and inquiry scanning. A channel is used for a 

very short period (e.g. 625 microseconds for data/voice links), followed by a hop designated by a predetermined pseudo-random sequence to another channel; this process is repeated continuously in the 

frequency-hopping sequence. 

Bluetooth also provides for radio link power control, where devices can negotiate and adjust their radio 

power according to signal strength measurements. Each device in a Bluetooth network can determine its 

received signal strength indication (RSSI) and make a request of the other network device to adjust its 

relative radio power level (i.e., have the transmission power incrementally increased or decreased). This 

is performed to conserve power and/or to keep the received signal characteristics within a preferred range. 

The combination of a frequency-hopping scheme and radio link power control provide Bluetooth with 

some additional, albeit limited, protection from eavesdropping and malicious access. The frequencyhopping scheme, primarily a technique to avoid interference, makes it slightly more difficult for an 

adversary to locate and capture Bluetooth transmissions than transmission from direct sequence spread 

spectrum technologies, like those using IEEE 802.11a/b/g. If the Bluetooth power control feature is used 

appropriately, any potential adversary is forced to be in relatively close proximity to pose a threat to a 

Bluetooth piconet, especially if the Bluetooth devices are very close to each other. 

Bluetooth versions 1.1 and 1.2 specify transmission speeds of up to 1 megabit per second (Mbps) and 

achieve throughput of approximately 720 kilobits per second (kbps). Bluetooth versions 2.0 + Enhanced 

Data Rate (EDR) and 2.1 + EDR specify data rates up to 3 Mbps and throughput of approximately 2.1 

Mbps. 

The range of Bluetooth devices is characterized by three classes that define power management. Table 2-

1 summarizes the classes, including their power levels in milliwatts (mW) and decibels referenced to one 

milliwatt (dBm), and their operating ranges in meters (m).4

 Most small, battery-powered devices are 

Class 2, while Class 1 devices are typically USB dongles for desktop and laptop computers, as well as 

access points and other AC-powered devices. 

Table 2-1. Bluetooth Device Classes of Power Management 

Type Power Power Level Designed Operating Range Sample Devices 

Class 1 High 100 mW (20 dBm) Up to 91 meters (300 feet) AC-powered devices (USB dongles, 

access points)

Class 2 Medium 2.5 mW (4 dBm) Up to 9 meters (30 feet) 

Battery-powered devices (mobile 

devices, Bluetooth adapters, smart 

card readers)

Class 3 Low 1 mW (0 dBm) Up to 1 meter (3 feet) Battery-powered devices (Bluetooth 

adapters)

So that Bluetooth devices can find and establish communication with each other, discoverable and 

connectable modes are specified. A device in discoverable mode periodically listens on an inquiry scan 

physical channel (based on a specific set of frequencies) and will respond to an inquiry on that channel 

with its device address, local clock, and other characteristics needed to page and subsequently connect to 

it. A device in connectable mode periodically listens on its page scan physical channel and will respond 

to a page on that channel to initiate a network connection. The frequencies associated with the page scan 

 

4

 The ranges listed in Table 2-1 are the designed operating ranges. Attackers may be able to intercept communications at 

significantly larger distances, especially if they use high gain antennas. 

2-2 
GUIDE TO BLUETOOTH SECURITY

physical channel for a device are based on its Bluetooth device address. Therefore, knowing a device’s 

address and clock5

 is important for paging and subsequently connecting to the device. 

2.2 Bluetooth Architecture 

Bluetooth permits devices to establish either ad hoc or infrastructure networks. Infrastructure networks 

use fixed Bluetooth access points (AP), which facilitate communication between Bluetooth devices. This 

document focuses on ad hoc piconets, which are much more common than infrastructure networks. Ad 

hoc networks provide easy connection establishment between mobile devices in the same physical area 

(e.g., the same room) without the use of any infrastructure devices. A Bluetooth client is simply a device 

with a Bluetooth radio and software incorporating the Bluetooth protocol stack and interfaces. 

The Bluetooth specification provides separation of duties for performing stack functions between a host 

and a host controller. The host is responsible for the higher layer protocols, such as Logical Link Control 

and Adaptation Protocol (L2CAP) and Service Discovery Protocol (SDP). The host functions are 

performed by a computing device like a laptop or desktop computer. The host controller is responsible 

for the lower layers, including the Radio, Baseband, and Link Manager Protocol (LMP). The host 

controller functions are performed by an integrated or external (e.g., USB) Bluetooth dongle. The host 

and host controller send information to each other using the Host Controller Interface (HCI). In many 

cases, the host and host controller functions are integrated into a single device, with Bluetooth headsets 

being a prime example. 

Figure 2-1 depicts the basic Bluetooth network topology. In a piconet, one device serves as the master, 

with all other devices in the piconet acting as slaves. Piconets can scale to include up to seven active 

slave devices and up to 255 inactive slave devices. 

Figure 2-1. Bluetooth Ad Hoc Topology 

The master device controls and establishes the network (including defining the network’s frequency 

hopping scheme). Although only one device can serve as the master for each piconet, time division 

 

5

 Having a remote device’s clock information is not needed to make a connection, but it will speed up the connection process. 

2-3 
GUIDE TO BLUETOOTH SECURITY

multiplexing (TDM) allows a slave in one piconet to act as the master for another piconet simultaneously, 

thus creating a chain of networks.6

 This chain, called a scatternet, allows several devices to be networked 

over an extended distance in a dynamic topology that can change during any given session. As a device 

moves toward or away from the master device, the topology, and therefore the relationships of the devices 

in the immediate network, may change. Figure 2-2 depicts a scatternet that connects three piconets. 

Figure 2-2. Bluetooth Networks (Multiple Scatternets) 

Routing capabilities supported by Bluetooth networks control the changing network topologies of 

piconets and scatternets and assist in controlling the flow of data between networked devices. Bluetooth 

uses a combination of packet-switching and circuit-switching technologies. The use of packet switching 

in Bluetooth allows devices to route multiple packets of information over the same data path. This 

method does not consume all the resources of a data path, thereby allowing Bluetooth devices to maintain 

data flow throughout a scatternet. 

 

6

 Note that a particular device can only be the master of one piconet at any given time. 

2-4 
GUIDE TO BLUETOOTH SECURITY

3. Bluetooth Security Features 

This section provides an overview of the security mechanisms included in the Bluetooth specifications to 

illustrate their limitations and provide a foundation for some of the security recommendations in Section 

4. A high-level example of the scope of the security for the Bluetooth radio path is depicted in Figure 3-

1. In this example, Bluetooth security is provided only between the mobile phone and the laptop 

computer, while IEEE 802.11 security protects the wireless local area network link between the laptop 

and the IEEE 802.11 AP. However, the communications on the wired network are not protected by 

Bluetooth or IEEE 802.11 security capabilities. End-to-end security is not possible without using higherlayer security solutions in addition to the security features included in the Bluetooth specification and 

IEEE 802.11 standards. 

Figure 3-1. Bluetooth Air-Interface Security 

The following are the three basic security services specified in the Bluetooth standard: 

 Authentication: verifying the identity of communicating devices. User authentication is not 

provided natively by Bluetooth. 

 Confidentiality: preventing information compromise caused by eavesdropping by ensuring that only 

authorized devices can access and view data. 

 Authorization: allowing the control of resources by ensuring that a device is authorized to use a 

service before permitting it to do so. 

The three security services offered by Bluetooth and details about the modes of security are described 

below. Bluetooth does not address other security services such as audit and non-repudiation; if such 

services are needed, they must be provided through additional means. 

3-1 
GUIDE TO BLUETOOTH SECURITY

3.1 Security Features of Bluetooth Specifications 

Cumulatively, the various versions of Bluetooth specifications define four security modes. Each version 

of Bluetooth supports some, but not all, of the four modes. Each Bluetooth device must operate in one of 

the four modes, which are described below. 

Security Mode 1 is non-secure. Security functionality (authentication and encryption) is bypassed, 

leaving the device and connections susceptible to attackers. In effect, Bluetooth devices in this mode are 

“promiscuous” and do not employ any mechanisms to prevent other Bluetooth-enabled devices from 

establishing connections. Security Mode 1 is only supported in v2.0 + EDR (and earlier) devices. 

In Security Mode 2, a service level-enforced security mode, security procedures are initiated after LMP 

link establishment but before L2CAP channel establishment. L2CAP resides in the data link layer and 

provides connection-oriented and connectionless data services to upper layers. For this security mode, a 

security manager (as specified in the Bluetooth architecture) controls access to specific services and 

devices. The centralized security manager maintains policies for access control and interfaces with other 

protocols and device users. Varying security policies and trust levels to restrict access may be defined for 

applications with different security requirements operating in parallel. It is possible to grant access to 

some services without providing access to other services. In this mode, the notion of authorization—the 

process of deciding if a specific device is allowed to have access to a specific service—is introduced. It is 

important to note that the authentication and encryption mechanisms used for Security Mode 2 are 

implemented at the LMP layer (below L2CAP), just as with Security Mode 3. All Bluetooth devices can 

support Security Mode 2; however, v2.1 + EDR devices can only support it for backward compatibility 

with v2.0 + EDR (or earlier) devices. 

In Security Mode 3, the link level-enforced security mode, a Bluetooth device initiates security 

procedures before the physical link is fully established. Bluetooth devices operating in Security Mode 3 

mandates authentication and encryption for all connections to and from the device. This mode supports 

authentication (unidirectional or mutual) and encryption. The authentication and encryption features are 

based on a separate secret link key that is shared by paired devices, once the pairing has been established. 

Security Mode 3 is only supported in v2.0 + EDR (or earlier) devices. 

Similar to Security Mode 2, Security Mode 4 (introduced in Bluetooth v2.1 + EDR) is a service level 

enforced security mode in which security procedures are initiated after link setup. Secure Simple Pairing 

uses Elliptic Curve Diffie Hellman (ECDH) techniques for key exchange and link key generation. Device 

authentication and encryption algorithms are identical to the algorithms in Bluetooth v2.0 + EDR and 

earlier versions. Security requirements for services protected by Security Mode 4 must be classified as 

one of the following: authenticated link key required, unauthenticated link key required, or no security 

required. Whether or not a link key is authenticated depends on the Secure Simple Pairing association 

model used. See Section 3.2.2 for a description of Secure Simple Pairing. Security Mode 4 is mandatory 

for communication between v2.1 + EDR devices. 

The rest of this section discusses specific Bluetooth security components in more detail: link key 

generation, authentication, confidentiality, and other Bluetooth security mechanisms. 

3.2 Link Key Generation 

As mentioned in Section 3.1, there are two methods in which link key generation is performed for 

Bluetooth. Security Modes 2 and 3 use one method, while Security Mode 4 uses another. Both methods 

are described below. 

3-2 
GUIDE TO BLUETOOTH SECURITY

3.2.1 Security Modes 2 and 3 

For Bluetooth v2.0 + EDR (and earlier), operating in Security Mode 2 or 3, two associated devices 

simultaneously derive link keys during the initialization phase when users enter an identical PIN into one 

or both devices, depending on the configuration and device type. The PIN entry, device association, and 

key derivation are depicted conceptually in Figure 3-2. Note that if the PIN is less than 16 bytes, the 

BD_ADDR is used to supplement the PIN value used to generate the initialization key. The Ex boxes 

represent encryption algorithms that are used during the Bluetooth device association and key derivation 

processes. More details on the Bluetooth authentication and encryption procedures are outlined in 

Sections 3.4 and 3.5, respectively. 

Figure 3-2. Link Key Generation from PIN (v2.0 & earlier) 

3-3 
GUIDE TO BLUETOOTH SECURITY

After initialization is complete, devices automatically and transparently authenticate and initiate the 

encryption procedure to secure the wireless link, if encryption is enabled. The PIN code used in 

Bluetooth devices can vary between one and 16 bytes. The typical four-digit PIN may be sufficient for 

low-risk situations; a longer PIN should be used for devices that require a higher level of security.7

3.2.2 Security Mode 4 

Secure Simple Pairing (SSP) was introduced in Bluetooth v2.1 + EDR for use with Security Mode 4. SSP 

simplifies the pairing process by providing a number of association models that are flexible in terms of 

device input capability. SSP also improves security through the addition of ECDH public key 

cryptography for protection against passive eavesdropping and man-in-the-middle attacks (MITM) during 

pairing. 

The four association models offered in SSP are as follows:8

 Numeric Comparison was designed for the situation where both Bluetooth devices are capable of 

displaying a six-digit number and allowing a user to enter a “yes” or “no” response. During pairing, a 

user is shown a six-digit number on each display and provides a “yes” response on each device if the 

numbers match. Otherwise, the user responds “no” and pairing will fail. A key difference between 

this operation and the use of PINs in legacy pairing is that the displayed number is not used as input 

to subsequent link key generation. An attacker who is able to view (or otherwise capture) the 

displayed value could not use it to determine the resulting link or encryption key. 

 Passkey Entry was designed for the situation where one Bluetooth device has input capability (e.g., 

Bluetooth-enabled keyboard), while the other device has a display but no input capability. In this 

model, the device with only a display shows a six-digit number that the user then enters on the device 

with input capability. As with the Numeric Comparison model, the six-digit number used in this 

transaction is not incorporated into link key generation and hence is of no value to an attacker. 

 Just Works was designed for the situation where one (or both) of the pairing devices has neither a 

display nor a keyboard for entering digits (e.g., Bluetooth-enabled headset). It performs 

Authentication Stage 1 (see Figure 3-3 below) in the same manner as the Numeric Comparison 

model, except that a display is not available. The user is required to accept a connection without 

verifying the calculated value on both devices, so MITM protection is not provided. 

 Out of Band (OOB) was designed for devices that support a wireless technology other than 

Bluetooth (e.g., Near Field Communication [NFC]) for the purposes of device discovery and 

cryptographic value exchange. In the case of NFC, the OOB model allows devices to pair by simply 

“tapping” one device against the other, followed by the user accepting the pairing via a single button 

push. It is important to note that the chosen OOB wireless technology should be configured to 

mitigate eavesdropping and MITM attacks to keep the pairing process as secure as possible. 

Security Mode 4 requires Bluetooth services to mandate an authenticated link key, an unauthenticated 

link key, or no security at all. Of the association models described above, all but the Just Works model 

provide authenticated link keys. 

 

7

 The Bluetooth Security White Paper from the Bluetooth Special Interest Group is available at 

http://www.bluetooth.com/NR/rdonlyres/E870794C-2788-49BF-96D3-C9578E0AE21D/0/security_whitepaper_v1.pdf. 8

 This information is derived from “Simple Pairing Whitepaper”, written by the Bluetooth Special Interest Group, August 

2006. The paper is available at http://bluetooth.com/NR/rdonlyres/0A0B3F36-D15F-4470-85A6-

F2CCFA26F70F/0/SimplePairing_WP_V10r00.pdf. 

3-4 
GUIDE TO BLUETOOTH SECURITY

Figure 3-3 shows how the link key is established for SSP. Note how this technique uses ECDH 

public/private key pairs rather than generating a symmetric key via a PIN. 

Figure 3-3. Link Key Establishment for Secure Simple Pairing 

3.3 Authentication 

The Bluetooth device authentication procedure is in the form of a challenge-response scheme. Each 

device interacting in an authentication procedure is referred to as either the claimant or the verifier. The 

claimant is the device attempting to prove its identity, and the verifier is the device validating the identity 

of the claimant. The challenge-response protocol validates devices by verifying the knowledge of a secret 

key—the Bluetooth link key. The challenge-response verification scheme is depicted conceptually in 

Figure 3-4. 

3-5 
GUIDE TO BLUETOOTH SECURITY

Figure 3-4. Bluetooth Authentication 

The steps in the authentication process are as follows: 

 Step 1. The verifier transmits a 128-bit random challenge (AU_RAND) to the claimant. 

 Step 2. The claimant uses the E1 algorithm9

 to compute an authentication response using his unique 

48-bit Bluetooth device address (BD_ADDR), the link key, and AU_RAND as inputs. The verifier 

performs the same computation. Only the 32 most significant bits of the E1 output are used for 

authentication purposes. The remaining 96 bits of the 128-bit output are known as the Authenticated 

Ciphering Offset (ACO) value, which will be used later to create the Bluetooth encryption key. 

 Step 3. The claimant returns the most significant 32 bits of the E1 output as the computed response, 

SRES, to the verifier. 

 Step 4. The verifier compares the SRES from the claimant with the value that it computed. 

 Step 5. If the two 32-bit values are equal, the authentication is considered successful. If the two 32-

bit values are not equal, the authentication has failed. 

Performing these steps once accomplishes one-way authentication. The Bluetooth standard allows both 

one-way and mutual authentication to be performed. For mutual authentication, the above process is 

repeated with the verifier and claimant switching roles. 

 

9

 The E1 authentication function is based on the SAFER+ algorithm. SAFER stands for Secure And Fast Encryption Routine. 

The SAFER algorithms are iterated block ciphers (IBC). In an IBC, the same cryptographic function is applied for a 

specified number of rounds. 

3-6 
GUIDE TO BLUETOOTH SECURITY

If authentication fails, a Bluetooth device waits an interval of time before a new attempt is made. This 

time interval increases exponentially to prevent an adversary from attempting to gain access by defeating 

the authentication scheme through trial-and-error with different keys. It is important to note that this 

suspend technique does not provide security against sophisticated adversaries performing offline attacks 

to exhaustively search PINs. 

Note that the security associated with authentication is solely based on the secrecy of the link key. While 

the Bluetooth device addresses and random challenge value are considered public parameters, the link key 

is not. The link key is derived during pairing and is never disclosed outside the Bluetooth device or 

transmitted over wireless links. The link key is passed in the clear from the host to the host controller 

(e.g., PC to USB dongle) if the host is used for key storage. The random challenge, which is a public 

parameter associated with the authentication process, is designed to be different for every transaction. 

The random number is derived from a pseudo-random process within the Bluetooth device. The 

cryptographic response is public as well and part of the encryption establishment process. 

3.4 Confidentiality 

In addition to the Security Modes, Bluetooth provides a separate confidentiality service to thwart 

eavesdropping attempts on the payloads of the packets exchanged between Bluetooth devices. Bluetooth 

has three Encryption Modes, but only two of them actually provide confidentiality. The modes are as 

follows: 

 Encryption Mode 1—No encryption is performed on any traffic. 

 Encryption Mode 2—Individually addressed traffic is encrypted using encryption keys based on 

individual link keys; broadcast traffic is not encrypted. 

 Encryption Mode 3—All traffic is encrypted using an encryption key based on the master link key. 

Encryption Modes 2 and 3 use the same encryption mechanism. 

As shown in Figure 3-5, the encryption key provided to the encryption algorithm is produced using an 

internal key generator (KG). The KG produces stream cipher keys based on the 128-bit link key, which is 

a secret that is held in the Bluetooth devices, a 128-bit random number (EN_RAND), and the 96-bit ACO 

value. The ACO is produced during the authentication procedure, as shown in Figure 3-4. 

The Bluetooth encryption procedure is based on a stream cipher, E0. A key stream output is exclusiveOR-ed with the payload bits and sent to the receiving device. This key stream is produced using a 

cryptographic algorithm based on linear feedback shift registers (LFSR).10 The encryption function takes 

the following as inputs: the master identity (BD_ADDR), the 128-bit random number (EN_RAND), a slot 

number, and an encryption key, which when combined initialize the LFSRs before the transmission of 

each packet, if encryption is enabled. The slot number used in the stream cipher changes with each 

packet; the ciphering engine is also reinitialized with each packet while the other variables remain static. 

 

10 LFSRs are used in coding (error control coding) theory and cryptography. LFSR-based key stream generators (KSG), 

composed of exclusive-OR gates and shift registers, are common in stream ciphers and are very fast in hardware. 

3-7 
GUIDE TO BLUETOOTH SECURITY

Figure 3-5. Bluetooth Encryption Procedure 

The encryption key (KC) is generated from the current link key and may vary from eight bits to 128 bits. 

The key size negotiation process occurs between the master and slave devices. During negotiation, a 

master device makes a key size suggestion for the slave. The initial key size suggested by the master is 

programmed into the host controller by the manufacturer and is not always 128-bit. In product 

implementations, a “minimum acceptable” key size parameter can be set to prevent a malicious user from 

driving the key size down to the minimum of eight bits, making the link less secure. 

It is important to note that E0 is not a Federal Information Processing Standards (FIPS) approved 

algorithm and has come under scrutiny recently in terms of algorithmic strength.11 A recently published 

theoretical known-plaintext attack has been discovered that can recover the encryption key in 238

computations, as compared to a brute force attack, which would require the testing of 2128 possible keys. 

If communications require FIPS-approved cryptographic protection (e.g., sensitive information 

 

11 Y. Lu, W. Meier, and S. Vaudenay. “The Conditional Correlation Attack: A Practical Attack on Bluetooth Encryption”. 

http://lasecwww.epfl.ch/pub/lasec/doc/LMV05.pdf

3-8 
GUIDE TO BLUETOOTH SECURITY

transmitted by Federal agencies), this can be achieved by employing application-level FIPS-approved 

encryption over the native Bluetooth encryption. 

3.5 Trust Levels, Service Levels, and Authorization 

In addition to the four security modes, Bluetooth allows two levels of trust and three levels of service 

security. The two Bluetooth levels of trust are trusted and untrusted. A trusted device has a fixed 

relationship with another device and has full access to all services. An untrusted device does not have an 

established relationship with another Bluetooth device, which results in the untrusted device receiving 

restricted access to services. Three levels of security have been defined for Bluetooth services. These 

levels allow the requirements for authorization, authentication, and encryption to be configured and 

altered independently. The service security levels are as follows: 

 Service Level 1—Requires authorization and authentication. Automatic access is granted only to 

trusted devices; untrusted devices need manual authorization. 

 Service Level 2—Requires authentication only; authorization is not necessary. Access to an 

application is allowed only after an authentication procedure. 

 Service Level 3—Open to all devices, with no authentication required. Access is granted 

automatically. 

The Bluetooth architecture allows for defining security policies that can set trust relationships in such a 

way that even trusted devices can get access only to specific services. It is important to understand that 

although Bluetooth core protocols can only authenticate devices and not users, it is possible to initiate 

user-based authentication in an alternative manner. The Bluetooth security architecture (through the 

security manager) allows applications to enforce more granular security policies. The link layer, at which 

Bluetooth-specific security controls operate, is transparent to the security controls imposed by the 

application layers. Thus, it is possible to enforce user-based authentication and fine-grained access 

control within the Bluetooth security framework through the application layers. 

3-9 
GUIDE TO BLUETOOTH SECURITY

4. Bluetooth Vulnerabilities, Threats, and Countermeasures 

This section describes vulnerabilities in Bluetooth technologies and threats against those vulnerabilities. 

Based on the common vulnerabilities and threats, as well as the Bluetooth security features described in 

Section 3, this section also makes recommendations for possible countermeasures that can be used to 

improve Bluetooth security. 

Organizations that are planning countermeasures for Bluetooth technologies that use the v2.1 + EDR 

specification should carefully consider its security implications. The specification was released in mid2007, and as of mid-2008, few products that support the specification are yet available. As the 

specification becomes more widely adopted, it is likely that additional vulnerabilities will be discovered 

and additional recommendations needed for securing v2.1 technologies effectively. Organizations 

planning on deploying v2.1 technologies should monitor developments involving new vulnerabilities and 

threats and additional security control recommendations. 

4.1 Bluetooth Vulnerabilities 

Table 4-1 below provides an overview of some of the known security vulnerabilities with Bluetooth. The 

Bluetooth security checklist in Section 4.4 addresses these vulnerabilities. 

Table 4-1. Key Problems with Existing (Native) Bluetooth Security 

Security Issue or Vulnerability Remarks 

Versions Before Bluetooth v1.2

1 Unit key is reusable and becomes public 

once used. 

A unit key should be used as input to generate a 

random key. A key set should be used instead of only 

one unit key. 

2 Unit key sharing can lead to eavesdropping. A corrupt user may be able to compromise the 

security between two other users if the corrupt user 

has communicated with either of the other two users. 

This is because the link key (unit key), derived from 

shared information, has been disclosed. 

Versions Before Bluetooth v2.1

3 Short PINs are allowed. Weak PINs, which are used for the generation of link 

and encryption keys, can be easily guessed. People 

have a tendency to select short PINs. 

4 PIN management is lacking. Establishing use of adequate PINs in an enterprise 

setting with many users may be difficult. Scalability 

problems frequently yield security problems. 

5 Encryption keystream repeats after 23.3 

hours of use. 

Per Figure 3-5, the encryption keystream is 

dependent on the link key, EN_RAND, Master 

BD_ADDR, and Clock. Only the Master’s clock will 

change during a particular encrypted connection. If a 

connection lasts more than 23.3 hours, the clock 

value will begin to repeat, hence generating an 

identical keystream to that used earlier in the 

connection. 

All Versions

6 Link keys are stored improperly. Link keys can be read or modified by an attacker if 

they are not securely stored and protected via access 

controls. 

4-1 
GUIDE TO BLUETOOTH SECURITY

Security Issue or Vulnerability Remarks 

7 Attempts for authentication are repeated. A limiting feature needs to be incorporated in the 

specification to prevent unlimited requests. The 

Bluetooth specification currently requires a time-out 

period between repeated attempts that will increase 

exponentially. 

8 Strength of the challenge-response pseudorandom generator is not known. 

The Random Number Generator (RNG) may produce 

static number or periodic numbers that may reduce 

the effectiveness of the authentication scheme. 

9 Encryption key length is negotiable. The specification allows devices to negotiate 

encryption keys as small as one byte. A more robust 

encryption key generation procedure needs to be 

incorporated in the specification. 

10 The master key is shared. A better broadcast keying scheme needs to be 

incorporated into the specification. 

11 No user authentication exists. Only device authentication is provided by the 

specification. Application-level security, including 

user authentication, can be added via overlay by the 

application developer. 

12 The E0 stream cipher algorithm used for 

Bluetooth encryption is weak. 

More robust encryption needs to be incorporated in 

the specification. 

13 Privacy may be compromised if the 

Bluetooth device address (BD_ADDR) is 

captured and associated with a particular 

user. 

Once the BD_ADDR is associated with a particular 

user, that user’s activities could be logged, resulting 

in a loss of privacy. 

14 Device authentication is simple shared-key 

challenge-response. 

One-way-only challenge-response authentication is 

subject to MITM attacks. Bluetooth provides for 

mutual authentication, which should be used to 

provide verification that users and the network are 

legitimate. 

15 End-to-end security is not performed. Only individual links are encrypted and authenticated. 

Data is decrypted at intermediate points. End-to-end 

security on top of the Bluetooth stack can be provided 

by use of additional security controls. 

16 Security services are limited. Audit, nonrepudiation, and other services are not part 

of the standard. If needed, these services can be 

incorporated in an overlay fashion by the application 

developer. 

17 Discoverable and/or connectable devices 

are prone to attack. 

Any device that must go into discoverable or 

connectable mode to pair should only do so for a 

minimal amount of time. A device should never be in 

discoverable or connectable mode all the time. 

4.2 Bluetooth Threats 

Bluetooth offers several benefits and advantages, but the benefits of Bluetooth are not provided without 

risk. Bluetooth technology and associated devices are susceptible to general wireless networking threats, 

such as denial of service attacks, eavesdropping, man-in-the-middle attacks, message modification, and 

resource misappropriation,12 and are also threatened by more specific Bluetooth-related attacks, such as 

the following: 

 

12 Additional information on general wireless security threats is available in Section 3 of NIST SP 800-48 Revision 1, Guide to 

Securing Legacy IEEE 802.11 Wireless Networks (http://csrc.nist.gov/publications/nistpubs/800-48-rev1/SP800-48r1.pdf). 

4-2 
GUIDE TO BLUETOOTH SECURITY

 Bluesnarfing. Bluesnarfing13 enables attackers to gain access to a Bluetooth-enabled device by 

exploiting a firmware flaw in older devices. This attack forces a connection to a Bluetooth device, 

allowing access to data stored on the device and even the device’s international mobile equipment 

identity (IMEI). The IMEI is a unique identifier for each device that an attacker could potentially use 

to route all incoming calls from the user’s device to the attacker’s device. 

 Bluejacking. Bluejacking is an attack conducted on Bluetooth-enabled mobile devices, such as 

cellular telephones, smart phones, and PDAs. Bluejacking is initiated by an attacker sending 

unsolicited messages to a user of a Bluetooth-enabled device. The actual messages do not cause harm 

to the user’s device, but they are used to entice the user to respond in some fashion or add the new 

contact to the device’s address book. This message-sending attack resembles spam and phishing 

attacks conducted against email users. Bluejacking can cause harm when a user initiates a response to 

a bluejacking message that is sent with a harmful intent. 

 Bluebugging. Bluebugging14 exploits a security flaw in the firmware of some older Bluetooth 

devices to gain access to the device and its commands. This attack uses the commands of the device 

without informing the user, allowing the attacker to access data, place telephone calls, eavesdrop on 

telephone calls, send messages, and exploit other services or features offered by the device. 

 Car Whisperer. Car Whisperer15 is a software tool developed by European security researchers that 

exploits a key implementation issue in hands-free Bluetooth car kits installed in automobiles. The car 

whisperer software allows an attacker to send to or receive audio from the car kit. An attacker could 

transmit audio to the car’s speakers or receive audio (eavesdrop) from the microphone in the car. 

 Denial of Service. Bluetooth is susceptible to DoS attacks. Impacts include making a device’s 

Bluetooth interface unusable and draining the mobile device’s battery. These types of attacks are not 

significant and, due to the proximity required for Bluetooth use, can usually be easily averted by 

simply walking away. 

 Fuzzing Attacks. Bluetooth fuzzing attacks consist of sending malformed or otherwise non-standard 

data to a device’s Bluetooth radio and observing how the device reacts. When a device’s response is 

slowed or stopped by these attacks, this indicates that a serious vulnerability potentially exists in the 

protocol stack. 

4.3 Risk Mitigation and Countermeasures 

Organizations should mitigate risks to their Bluetooth implementations by applying countermeasures to 

address specific threats and vulnerabilities. Some of these countermeasures cannot be achieved through 

security features built into the Bluetooth specifications. The countermeasures recommended in the 

checklists in Section 4.4 do not guarantee a secure Bluetooth environment and cannot prevent all 

adversary penetrations. Also, security comes at a cost—financial expenses related to security equipment, 

inconvenience, maintenance, and operation. Each organization needs to evaluate the acceptable level of 

risk based on numerous factors, which will affect the level of security implemented by that organization. 

To be effective, Bluetooth security should be incorporated throughout the entire life cycle of Bluetooth 

solutions.16 

 

13 http://trifinite.org/trifinite_stuff_bluesnarf.html 14 http://trifinite.org/trifinite_stuff_bluebug.html 15 http://trifinite.org/trifinite_stuff_carwhisperer.html 16 For more information about technology life cycles, see NIST SP 800-64, Security Considerations in the Information System 

Development Life Cycle (http://csrc.nist.gov/publications/PubsSPs.html). 

4-3 
GUIDE TO BLUETOOTH SECURITY

FIPS Publication (PUB) 199 establishes three security categories—low, moderate, and high—based on 

the potential impact of a security breach involving a particular system. NIST SP 800-53 provides 

recommendations for minimum management, operational, and technical security controls for information 

systems based on the FIPS PUB 199 impact categories.17 The recommendations in NIST SP 800-53 

should be helpful to organizations in identifying controls that are needed to protect Bluetooth 

implementations in general, which should be used in addition to the specific recommendations for 

Bluetooth implementations listed in this document. 

The first line of defense is to provide an adequate level of knowledge and understanding for those who 

will deal with Bluetooth-enabled devices. Organizations using Bluetooth technology should establish and 

document security policies that address the use of Bluetooth-enabled devices and users’ responsibilities. 

Organizations should include awareness-based education to support staff understanding and knowledge of 

Bluetooth. Policy documents should include a list of approved uses for Bluetooth, and the type of 

information that may be transferred over Bluetooth networks. The security policy should also specify a 

proper password usage scheme. When feasible, a centralized security policy management approach 

should be used in coordination with an endpoint security product installed on the Bluetooth devices to 

ensure that the policy is locally enforced. 

The general nature and mobility of Bluetooth-enabled devices increases the difficulty of employing 

traditional security measures. Nevertheless, a number of countermeasures can be enacted to secure 

Bluetooth devices and communications, ranging from distance and power output to general operation 

practices. Several countermeasures that could be employed are provided in the checklists in Section 4.4. 

4.4 Bluetooth Security Checklists 

This section provides Bluetooth security checklists. For each recommendation or guideline in a checklist, 

a justification column lists areas of concern for Bluetooth devices, the security threats and vulnerabilities 

associated with those areas, risk mitigations for securing the devices from these threats, and 

vulnerabilities. In addition, for each recommendation and justification, a checklist with three columns is 

provided. The first column, the Recommended Practice column, if checked, means that this entry 

represents a recommendation for all organizations. The second column, the Should Consider column, if 

checked, means that the entry’s recommendation should be considered carefully by an organization for 

one or more of the following reasons. First, implementing the recommendation may provide a higher 

level of security for the wireless environment by offering some additional protection. Second, the 

recommendation supports a defense-in-depth strategy. Third, it may have significant performance, 

operational, or cost impacts. In summary, if the Should Consider column is checked, organizations 

should carefully consider the option and weigh the costs versus the benefits. The last column, Status, is 

intentionally left blank to allow organization representatives to use this table as a true checklist. For 

instance, an individual performing a wireless security audit in a Bluetooth environment can quickly check 

off each recommendation for the organization, asking, “Have I done this?” 

Table 4-2 provides a Bluetooth security checklist with guidelines and recommendations for creating and 

maintaining secure Bluetooth piconets. Additional checklists for Bluetooth headsets and smart card 

readers are located later in this section. 

 

17 FIPS PUB 199, Standards for Security Categorization of Federal Information and Information Systems, is available at 

http://csrc.nist.gov/publications/fips/fips199/FIPS-PUB-199-final.pdf. NIST SP 800-53 Revision 2, Recommended Security 

Controls for Federal Information Systems, is available at http://csrc.nist.gov/publications/nistpubs/800-53-Rev2/sp800-53-

rev2-final.pdf. 

4-4 
GUIDE TO BLUETOOTH SECURITY

Table 4-2. Bluetooth Piconet Security Checklist 

Checklist 

Security Recommendation Security Need, Requirement, or 

Justification 

Recommended 

Practice 

Should 

Consider Status 

Management Recommendations 

1 

Develop an organizational 

wireless security policy that 

addresses Bluetooth technology. 

A security policy is the foundation for 

all other countermeasures. 3

2 

Ensure that Bluetooth users on 

the network are made aware of 

their security-related 

responsibilities regarding 

Bluetooth use. 

A security awareness program helps 

users to follow security practices 

that help prevent security incidents.

3

3 

Perform comprehensive security 

assessments at regular intervals 

to fully understand the 

organization’s Bluetooth security 

posture. 

Bluetooth products should support 

upgrade and patching of firmware to 

be able to take advantage of 

Bluetooth security enhancements 

and fixes. 

3

4 

Ensure that wireless devices and 

networks involving Bluetooth 

technology are fully understood 

from an architecture perspective 

and documented accordingly. 

Bluetooth-enabled devices can 

contain various networking 

technologies and interfaces allowing 

connections to local and wide area 

networks. An organization must 

understand the overall connectivity 

of each device to identify possible 

risks and vulnerabilities. These risks 

and vulnerabilities can then be 

addressed in the wireless security 

policy. 

3

5 

Provide users with a list of 

precautionary measures they 

should take to better protect 

handheld Bluetooth devices from 

theft. 

The organization and its employees 

should be responsible for its 

wireless technology components 

because theft of those components 

could lead to malicious activities 

against the organization’s 

information system resource.

3

6 

Maintain a complete inventory of 

all Bluetooth-enabled wireless 

devices and addresses 

(BD_ADDRs). 

A complete inventory list of 

Bluetooth-enabled wireless devices 

can be referenced when conducting 

an audit that searches for 

unauthorized use of wireless 

technologies. 

3

Technical Recommendations 

7 

Change the default settings of 

the Bluetooth device to reflect 

the organization’s security policy. 

Because default settings are 

generally not secure, a careful 

review of those settings should be 

performed to ensure that they 

comply with the company security 

policy. 

3

4-5 
GUIDE TO BLUETOOTH SECURITY

Checklist 

Security Need, Requirement, or Security Recommendation RecomJustification Should mended Status Consider Practice 

8 

Set Bluetooth devices to the 

lowest necessary and sufficient 

power level so that transmissions 

remain within the secure 

perimeter of the organization. 

Setting Bluetooth devices to the 

lowest necessary and sufficient 

power level ensures a secure range 

of access to authorized users. The 

use of Class 1 devices should be 

avoided due to their extended range 

(approximately 100 meters). 

3

9 

Choose PIN codes that are 

sufficiently random and long. 

Avoid static and weak PINs, such 

as all zeroes. 

PIN codes should be random so that 

they cannot be easily guessed by 

malicious users. Longer PIN codes 

are more resistant to brute force 

attacks. For Bluetooth v2.0 (or 

earlier) devices, an eight-character 

alphanumeric PIN should be used, if 

possible. The use of a fixed PIN is 

not acceptable for sensitive 

Bluetooth connections. 

3

10 

Ensure that link keys are based 

on combination keys rather than 

unit keys. 

The use of shared unit keys can 

lead to successful MITM attacks. 

The use of unit keys for security was 

deprecated in Bluetooth v1.2. 

3 

11 

For v2.1 devices using Secure 

Simple Pairing, avoid using the 

“Just Works” model. 

The “Just Works” association model 

does not provide MITM protection. 

Devices that only support Just 

Works should not be procured if 

similarly qualified devices that 

support one of the other association 

models (i.e., Numeric Comparison, 

Out Of Band, or Passkey Entry) are 

available. 

3 

12 

Service and profile lockdown of 

device Bluetooth stacks should 

be performed.18

Many Bluetooth stacks are designed 

to support multiple profiles and 

associated services. The Bluetooth 

stack on a device should be locked 

down to ensure only approved 

profiles and services are available 

for use. 

3 

13 

Bluetooth devices should be 

configured by default as, and 

remain, undiscoverable except 

as needed for pairing. 

Bluetooth interfaces should be 

configured as non-discoverable, 

which prevents visibility to other 

Bluetooth devices except when 

discovery is specifically needed. 

Also, the default self-identifying or 

discoverable names provided on 

Bluetooth devices should be 

changed to anonymous, 

unidentifiable names. 

3 

 

18 Derived from requirement 6.0 in DoD’s Bluetooth Smart Card Reader Security Requirements Matrix (01 June 2007), 

available at http://iase.disa.mil/stigs/checklist/DoD-Bluetooth-Smart-Card-Reader-Security-Requirements-Matrix.pdf 

4-6 
GUIDE TO BLUETOOTH SECURITY

Checklist 

Security Need, Requirement, or Security Recommendation RecomJustification Should mended Status Consider Practice 

14 

Invoke link encryption for all 

Bluetooth connections regardless 

of how needless encryption may 

seem (i.e., no Security Mode 1). 

Link encryption should be used to 

secure all data transmissions during 

a Bluetooth connection, otherwise 

transmitted data is vulnerable to 

eavesdropping. 

3 

15 

If multi-hop wireless 

communication is being utilized, 

ensure that encryption is enabled 

on every link in the 

communication chain. 

Every link should be secured 

because one unsecured link results 

in compromising the entire 

communication chain. 

3 

16 

Ensure device mutual 

authentication is performed for all 

accesses. 

Mutual authentication is required to 

provide verification that all devices 

on the network are legitimate. 

3 

17 

Enable encryption for all 

broadcast transmissions 

(Encryption Mode 3). 

Broadcast transmissions secured by 

link encryption provide a layer of 

security that protects these 

transmissions from user interception 

for malicious purposes. 

3 

18 Configure encryption key sizes to 

the maximum allowable. 

Using maximum allowable key sizes 

provides protection from brute force 

attacks. 

3 

19 Establish a “minimum key size” 

for any key negotiation process. 

Establishing minimum key sizes 

ensures that all keys are long 

enough to be resistant to brute force 

attacks. Preferably, keys should be 

at least 128 bits long. 

3 

20 

Use application-level (on top of 

the Bluetooth stack) 

authentication and encryption for 

sensitive data communication. 

Bluetooth devices can access link 

keys from memory and automatically 

connect with previously paired 

devices. Incorporating applicationlevel software that implements 

authentication and encryption will 

add an extra layer of security. 

Passwords and other authentication 

mechanisms, such as biometrics 

and smart cards, can be used to 

provide user authentication for 

Bluetooth devices. Employing 

higher layer encryption (particularly 

FIPS 140-2 validated) over the 

native encryption will further protect 

the data in transit. 

3

21 

Deploy user authentication such 

as biometrics, smart cards, twofactor authentication, or public 

key infrastructure (PKI). 

Implementing strong authentication 

mechanisms can minimize the 

vulnerabilities associated with 

passwords and PINs. 

3

4-7 
GUIDE TO BLUETOOTH SECURITY

Checklist 

Security Need, Requirement, or Security Recommendation RecomJustification Should mended Status Consider Practice 

Operational Recommendations 

22 

Ensure that Bluetooth devices 

are turned off when they are not 

used. 

Bluetooth capabilities should be 

disabled on all Bluetooth devices, 

except when the user explicitly 

enables Bluetooth to establish a 

connection. Shutting down 

Bluetooth devices when not in use 

minimizes exposure to potential 

malicious activities. 

3 

23 

Perform pairing as infrequently 

as possible, ideally in a secure 

area where attackers cannot 

realistically observe the passkey 

entry and intercept Bluetooth 

pairing messages. (Note: A 

“secure area” is defined as a 

non-public area that is indoors 

away from windows in locations 

with physical access controls.) 

Users should not respond to any 

messages requesting a PIN, 

unless the user has initiated a 

pairing and is certain the PIN 

request is being sent by one of 

the user’s devices.19

Pairing is a vital security function 

and requires that users maintain a 

security awareness of possible 

eavesdroppers. If an attacker can 

capture the transmitted frames 

associated with pairing, determining 

the link key is straightforward for 

pre-v.2.1 devices (security is solely 

dependent on PIN entropy and 

length). This is also recommended 

for v2.1 devices, although similar 

attacks against Secure Simple 

Pairing have not yet been 

documented. 

3 

24 

A service-level security mode 

(i.e., Security Mode 2 or 4) 

should only be used in a 

controlled and well-understood 

environment. 

Security Mode 3 provides link-level 

security prior to link establishment, 

while Security Modes 2 and 4 allow 

link-level connections before any 

authentication or encryption is 

established. It is highly 

recommended that devices use 

Security Mode 3. (However, note 

that v2.1 devices cannot use 

Security Mode 3.) 

3

25 

Ensure that portable devices with 

Bluetooth interfaces are 

configured with a password to 

prevent unauthorized access if 

lost or stolen. 

Authenticating users to a portable 

Bluetooth device is a good security 

practice in the event the device is 

lost or stolen, which provides a layer 

of protection for an organization’s 

Bluetooth network. 

3

26 

In the event a Bluetooth device is 

lost or stolen, users should 

immediately unpair the missing 

device from all other Bluetooth 

devices with which it was 

previously paired. 

This will prevent an attacker from 

using the lost or stolen device to 

access another Bluetooth device 

owned by the user(s). 

3

 

19 Derived from requirement 2.2 in DoD’s Bluetooth Smart Card Reader Security Requirements Matrix (01 June 2007), 

available at http://iase.disa.mil/stigs/checklist/DoD-Bluetooth-Smart-Card-Reader-Security-Requirements-Matrix.pdf

4-8 
GUIDE TO BLUETOOTH SECURITY

Checklist 

Security Need, Requirement, or Security Recommendation RecomJustification Should mended Status Consider Practice 

27 

Install antivirus software on 

Bluetooth-enabled hosts that are 

frequently targeted by malware. 

Antivirus software should be 

installed on frequently targeted 

Bluetooth-enabled hosts to ensure 

that known malware is not 

introduced to the Bluetooth network. 

Organizations may also choose to 

deploy antivirus software on lessoften targeted Bluetooth-enabled 

hosts. 

3

28 

Fully test and deploy Bluetooth 

software patches and upgrades 

regularly. 

Newly discovered security 

vulnerabilities of vendor products 

should be patched to prevent 

malicious and inadvertent exploits. 

Patches should be fully tested 

before implementation to ensure that 

they work. 

3

29 

Users should not accept 

transmissions of any kind from 

unknown or suspicious devices. 

These types of transmissions 

include messages, files, and 

images. 

With the increase in the number of 

Bluetooth-enabled devices, it is 

important that users only establish 

connections with other trusted 

devices and only accept content 

from these trusted devices 

3 

30 

Fully understand the impacts of 

deploying any security feature or 

product prior to deployment. 

To ensure a successful deployment, 

an organization should fully 

understand the technical, security, 

operational, and personnel 

requirements prior to 

implementation. 

3 

31 

Designate an individual to track 

the progress of Bluetooth 

security products and standards 

(perhaps via the Bluetooth SIG) 

and the threats and 

vulnerabilities with the 

technology. 

An appointed individual designated 

to track the latest technology 

enhancements, standards (perhaps 

via Bluetooth SIG), and risks will 

help to ensure the continued secure 

use of Bluetooth. 

3

Table 4-3 provides guidelines and recommendations on Bluetooth headsets based on the Department of 

Defense’s (DoD) Bluetooth Headset Security Requirements Matrix (Version 2.0, 07 April 2008)20. These 

recommendations are only intended for situations where the organization is concerned about threats 

within physical range of the Bluetooth headset usage. Note that most commercially available Bluetooth 

headsets, handsets, and hands-free devices cannot be configured to meet the recommendations in Table 4-

3. Most of those devices do not provide encryption and often use a four-digit PIN with a default value 

like “0000” that cannot be changed. 

 

20 http://iase.disa.mil/stigs/checklist/dod_bluetooth_headset_security_requirements_matrix_v2-0_7april2008.pdf 

4-9 
GUIDE TO BLUETOOTH SECURITY

Table 4-3. Bluetooth Headset Security Checklist 

Checklist 

Security Recommendation Security Need, Requirement, or 

Justification 

Recommended 

Practice 

Should 

Consider Status 

1 Bluetooth v1.2 or later should be 

used. 

The Bluetooth 1.2 specification 

deprecated the use of unit keys for 

link key generation. It also included 

enhancements such as adaptive 

frequency hopping (AFH) which 

improved resistance to radio 

frequency interference in the 

crowded 2.4 GHz band (which is 

used by IEEE 802.11b/g and other 

protocols). 

3

2 Bluetooth radios should be Class 

2 or Class 3. 

Bluetooth Class 1 radios provide 

100mW of power with an 

approximate range of 100 meters, 

which facilitates discovery and 

eavesdropping by attackers.

3

3 

Bluetooth pairing passkeys 

should be at least eight decimal 

digits in length and generated 

randomly for each pairing. 

For pre-v2.1 devices, this is 

essential to prevent link key cracking 

if pairing messages have been 

successfully eavesdropped by an 

attacker. 

Note that v2.1 devices using the 

Numerical Comparison or Passkey 

Entry association models will always 

use a 6-digit passkey per the 

Bluetooth specification. This is 

currently deemed adequate since 

v2.1 passkeys used during Secure 

Simple Pairing—by design—cannot 

be used to derive the associated link 

key. 

3

4 

Perform pairing as infrequently 

as possible, ideally in a secure 

area where attackers cannot 

realistically observe the passkey 

entry and intercept Bluetooth 

pairing messages. (Note: A 

“secure area” is defined as a 

non-public area that is indoors 

away from windows in locations 

with physical access controls.) 

Key establishment is a vital security 

function and requires that users 

maintain a security awareness of 

possible eavesdroppers. If an 

attacker can capture the transmitted 

frames associated with pairing, 

determining the link key is 

straightforward for pre-v.2.1 devices 

(security is solely dependent on PIN 

entropy and length). This is also 

recommended for v2.1 devices, 

although similar attacks against 

Secure Simple Pairing have not yet 

been documented.

3

4-10 
GUIDE TO BLUETOOTH SECURITY

Checklist 

Security Need, Requirement, or Security Recommendation RecomJustification Should mended Status Consider Practice 

5 

The Bluetooth headset/audio 

gateway device should remain 

undiscoverable to other 

Bluetooth devices at all times 

other than the initial pairing 

process. It should only support 

the minimal amount of Bluetooth 

services required for use as a 

headset for a handheld device. 

While a Bluetooth device is in 

discoverable mode, any inquiring 

device within range can capture 

important connection information 

including device address and clock, 

which is the first stage of any 

Bluetooth attack.

3

6 

Bluetooth Security Mode 3 (link 

level security) should be used by 

both the headset and the audio 

gateway device along with 128-

bit Bluetooth encryption. 

Security Mode 3 provides link-level 

security, which requires 

authentication and encryption prior 

to link establishment. (However, 

note that v2.1 devices cannot use 

Security Mode 3.) 128-bit 

encryption is the maximum provided 

by the Bluetooth specification, so it 

should be used to mitigate potential 

attacks against lower entropy (weak) 

cryptographic keys. 

3

7 

Devices should support only a 

single headset connection 

between one headset and one 

handheld device or audio 

gateway device. 

Bluetooth headset support for 

multiple simultaneous connections 

would provide an additional attack 

vector. 

3

8 

The user should be able to 

authorize all initial incoming 

connection requests, and there 

should be an indication of any 

active Bluetooth link on both the 

handheld device and the 

Bluetooth headset. 

The user should be made aware of, 

and explicitly authorize, all 

connections associated with the 

headset to preclude potential 

attacks. 

3

9 

Bluetooth stack lockdown 

techniques should be used on 

the handheld device to disable 

unauthorized Bluetooth 

connections (headset profile and 

serial port profile are authorized). 

Unnecessary Bluetooth services, 

user controls, and applications 

should be either removed from 

the handheld device or reliably 

disabled permanently so that 

users cannot enable them. 

Note: This feature may already 

be included with the handheld 

device security policy manager. 

The Bluetooth stack on the handheld 

device should only support the 

minimal services/profiles approved 

for use. Supporting unauthorized 

services/profiles could introduce 

vulnerabilities. 

3

4-11 
GUIDE TO BLUETOOTH SECURITY

Table 4-4 provides recommendations on Bluetooth smart card readers based on DoD’s Bluetooth Smart 

Card Reader Security Requirements Matrix (01 June 2007)21. Note that FIPS-140 validated encryption is 

recommended in addition to native Bluetooth authentication and encryption. 

Table 4-4. Bluetooth Smart Card Reader Security Checklist 

Checklist 

Security Recommendation Security Need, Requirement, or 

Justification 

Recommended 

Practice 

Should 

Consider Status 

1 

Bluetooth mutual authentication, 

128-bit Bluetooth encryption, and 

FIPS 140-validated cryptography 

should all be used for all 

communications between the 

smart card reader and the host 

device. 

Strong authentication and encryption 

is essential to network security, 

especially wireless connections. 

Mutual authentication confirms both 

devices have the appropriate link 

key, and 128-bit encryption is the 

maximum key length provided by the 

Bluetooth specification. FIPS 140-

validated cryptography should also 

be used to compensate for 

weaknesses in the native Bluetooth 

encryption. 

3

2 

Bluetooth pairing passkeys 

should be at least eight decimal 

digits in length and generated 

randomly for each pairing. 

For pre-v2.1 devices, this is 

essential to prevent link key cracking 

if pairing messages have been 

successfully eavesdropped by an 

attacker. 

Note that v2.1 devices using the 

Numerical Comparison or Passkey 

Entry association models will always 

use a 6-digit passkey per the 

Bluetooth specification. This is 

currently deemed adequate since 

v2.1 passkeys used during Secure 

Simple Pairing—by design—cannot 

be used to derive the associated link 

key.

3

3 

Perform pairing as infrequently 

as possible, ideally in a secure 

area where attackers cannot 

realistically observe the passkey 

entry and intercept Bluetooth 

pairing messages. (Note: A 

“secure area” is defined as a 

non-public area that is indoors 

away from windows in locations 

with physical access controls.) 

Key establishment is a vital security 

function and requires that users 

maintain a security awareness of 

possible eavesdroppers. If an 

attacker can capture the transmitted 

frames associated with pairing, 

determining the link key is 

straightforward for pre-v.2.1 devices 

(security is solely dependent on PIN 

entropy and length). This is also 

recommended for v2.1 devices, 

although similar attacks against 

Secure Simple Pairing have not yet 

been documented. 

3

4 

Bluetooth mutual authentication 

should occur immediately after 

the initial establishment of any 

Bluetooth connection. 

Devices should authenticate each 

other as soon as possible and 

certainly before providing access to 

any offered services. 

3

 

21 http://iase.disa.mil/stigs/checklist/DoD-Bluetooth-Smart-Card-Reader-Security-Requirements-Matrix.pdf 

4-12 
GUIDE TO BLUETOOTH SECURITY

Checklist 

Security Need, Requirement, or Security Recommendation RecomJustification Should mended Status Consider Practice 

5 

The Bluetooth smart card reader 

should remain undiscoverable to 

other Bluetooth devices at all 

times other than the initial pairing 

process and cannot initiate 

Bluetooth connections on its 

own. It should only support the 

minimal amount of Bluetooth 

services required for use as a 

smart card reader for a single 

host device. 

While a Bluetooth device is in 

discoverable mode, any inquiring 

device within range can capture 

important connection information 

including device address and clock, 

which is the first stage of any 

Bluetooth attack.

3

6 

Unnecessary Bluetooth services, 

user controls, and applications 

should be either removed from 

the host device or reliably 

disabled permanently. 

The Bluetooth stack on the host 

device should only support the 

minimal features approved for use. 

Supporting other features could 

introduce vulnerabilities 

unnecessarily. 

3

7 

All Bluetooth profiles except for 

Serial Port Profile should be 

disabled at all times, and the 

user should not be able to enable 

them. 

Additional profiles could introduce 

vulnerabilities unnecessarily. The 

Serial Port Profile is the only profile 

needed for smart card readers. 

3

4-13 
GUIDE TO BLUETOOTH SECURITY

Appendix A—Glossary of Terms 

Selected terms used in the publication are defined below. 

Access Point (AP): A device that logically connects wireless client devices operating in infrastructure to 

one another and provides access to a distribution system, if connected, which is typically an 

organization’s enterprise wired network. 

Ad Hoc Network: A wireless network that dynamically connects wireless client devices to each other 

without the use of an infrastructure device, such as an access point or a base station. 

Claimant: The Bluetooth device attempting to prove its identity to the verifier during the Bluetooth 

connection process. 

Flooding: An attack in which an attacker sends large numbers of wireless messages at a high rate to 

prevent the wireless network from processing legitimate traffic. 

Infrared (IR): An invisible band of radiation at the lower end of the electromagnetic spectrum. It starts 

at the middle of the microwave spectrum and extends to the beginning of visible light. Infrared 

transmission requires an unobstructed line of sight between transmitter and receiver. 

Infrastructure Network: A wireless network that requires the use of an infrastructure device, such as an 

access point or a base station, to facilitate communication between client devices. 

Jamming: A device emitting electromagnetic energy on a wireless network’s frequency to make it 

unusable. 

Media Access Control (MAC): A unique 48-bit value that is assigned to a particular wireless network 

interface by the manufacturer. 

Piconet: A small Bluetooth network created on an ad hoc basis that includes two or more devices. 

Range: The maximum possible distance for communicating with a wireless network infrastructure or 

wireless client. 

Scatternet: A chain of piconets created by allowing one or more Bluetooth devices to each be a slave in 

one piconet and act as the master for another piconet simultaneously. A scatternet allows several devices 

to be networked over an extended distance. 

Verifier: The Bluetooth device that validates the identity of the claimant during the Bluetooth connection 

process.

Wireless Bridge: A device that links two wired networks, generally operating at two different physical 

locations, through wireless communications. 

Wireless Local Area Network (WLAN): A group of wireless AP and associated infrastructure within a 

limited geographic area, such as an office building or building campus, that is capable of radio 

communications. WLANs are usually implemented as extensions of existing wired LANs to provide 

enhanced user mobility. 

A-1
GUIDE TO BLUETOOTH SECURITY

Wireless Personal Area Network (WPAN): A small-scale wireless network that requires little or no 

infrastructure and operates within a short range. A WPAN is typically used by a few devices in a single 

room instead of connecting the devices with cables.

A-2
GUIDE TO BLUETOOTH SECURITY

Appendix B—Acronyms and Abbreviations 

Selected acronyms and abbreviations used in the publication are defined below. 

ACO Authenticated Cipher Offset 

AFH Adaptive Frequency Hopping 

AP Access Point 

dBm Decibels referenced to one milliwatt 

DISA Defense Information Systems Agency 

DoD Department of Defense 

ECDH Elliptic Curve Diffie Hellman

EDR Enhanced Data Rate 

FHSS Frequency Hopping Spread Spectrum 

FIPS Federal Information Processing Standard 

FISMA Federal Information Security Management Act 

GHz Gigahertz 

HCI Host Controller Interface 

IBC Iterated Block Ciphers

IEEE Institute of Electrical and Electronics Engineers 

IP Internet Protocol 

IPSec Internet Protocol Security 

IR Infrared 

ISM Industrial, Scientific, and Medical 

ITL Information Technology Laboratory 

Kbps Kilobits per second 

KG Key Generator 

KSG Key Stream Generator 

L2CAP Logical Link Control and Adaptation Protocol 

LAN Local Area Network 

LFSR Linear Feedback Shift Register 

LMP Link Manager Protocol 

MAC Medium Access Control 

Mbps Megabits per second 

MITM Man-in-the-Middle 

mW Milliwatt 

NFC Near Field Communication 

NIST National Institute of Standards and Technology 

OMB Office of Management and Budget 

OOB Out of Band 

B-1
GUIDE TO BLUETOOTH SECURITY

P2P Peer to Peer 

PC Personal Computer 

PDA Personal Digital Assistant 

PHY Physical Layer 

PIN Personal Identification Number 

PKI Public Key Infrastructure 

RF Radio Frequency 

RNG Random Number Generator 

RSSI Received Signal Strength Indication 

SAFER Secure And Fast Encryption Routine 

SDP Service Discovery Protocol 

SIG Special Interest Group 

SP Special Publication 

SRES Signed Response 

SSP Secure Simple Pairing 

TDM Time Division Multiplexing 

USB Universal Serial Bus 

WLAN Wireless Local Area Network 

WPAN Wireless Personal Area Networks 

B-2
GUIDE TO BLUETOOTH SECURITY

Appendix C—References 

The list below provides references for the publication. 

Bluetooth Special Interest Group, Bluetooth 2.0 and 2.1 specifications, 

http://www.bluetooth.com/Bluetooth/Technology/Building/Specifications/

Bluetooth Special Interest Group, “Bluetooth Security White Paper”, May 2002, 

http://www.bluetooth.com/NR/rdonlyres/E870794C-2788-49BF-96D3-

C9578E0AE21D/0/security_whitepaper_v1.pdf 

Bluetooth Special Interest Group, “Simple Pairing Whitepaper”, August 2006, 

http://bluetooth.com/NR/rdonlyres/0A0B3F36-D15F-4470-85A6-

F2CCFA26F70F/0/SimplePairing_WP_V10r00.pdf 

C. Gehrmann, J. Persson, and B. Smeets, Bluetooth Security, Artech House, 2004 

Defense Information Systems Agency (DISA), “DoD Bluetooth Headset Security Requirements Matrix”, 

Version 2.0, 07 April 2008, 

http://iase.disa.mil/stigs/checklist/dod_bluetooth_headset_security_requirements_matrix_v2-

0_7april2008.pdf

Defense Information Systems Agency (DISA), “DoD Bluetooth Smart Card Reader Security 

Requirements Matrix”, Version 2.0, 01 June 2007, http://iase.disa.mil/stigs/checklist/DoD-BluetoothSmart-Card-Reader-Security-Requirements-Matrix.pdf 

Y. Lu, W. Meier, and S. Vaudenay, “The Conditional Correlation Attack: A Practical Attack on Bluetooth 

Encryption”, http://lasecwww.epfl.ch/pub/lasec/doc/LMV05.pdf 

Y. Shaked and A. Wool, “Cracking the Bluetooth PIN”, In Proc. 3rd USENIX/ACM Conf. 

Mobile Systems, Applications, and Services (MobiSys), pages 39-50, Seattle, WA, June 2005 

C-1 
GUIDE TO BLUETOOTH SECURITY

Appendix D—Online Resources 

The lists below provide examples of online resources related to Bluetooth technologies and wireless 

network security that may be helpful to readers. 

Documents 

Name URL 

Bluetooth SIG Specifications http://www.bluetooth.com/Bluetooth/Technology/Building/Spe

cifications/

DoD Bluetooth Headset Security Requirements 

Matrix (Version 2.0, 07 April 2008) 

http://iase.disa.mil/stigs/checklist/dod_bluetooth_headset_sec

urity_requirements_matrix_v2-0_7april2008.pdf

DoD Bluetooth Smart Card Reader Security 

Requirements Matrix (Version 2.0, 01 June 2007) 

http://iase.disa.mil/stigs/checklist/DoD-Bluetooth-Smart-CardReader-Security-Requirements-Matrix.pdf 

FIPS 140-2, Security Requirements for 

Cryptographic Modules

http://csrc.nist.gov/publications/fips/fips140-2/fips1402.pdf

FIPS 180-2, Secure Hash Standard (SHS) http://csrc.nist.gov/publications/fips/fips180-2/fips180-

2withchangenotice.pdf 

FIPS 197, Advanced Encryption Standard http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf

FIPS 199, Standards for Security Categorization of 

Federal Information and Information Systems

http://csrc.nist.gov/publications/fips/fips199/FIPS-PUB-199-

final.pdf 

GAO-05-383, Information Security: Federal 

Agencies Need to Improve Controls over Wireless

Networks

http://www.gao.gov/new.items/d05383.pdf 

GRS 24, Information Technology Operations and 

Management Records 

http://www.archives.gov/records-mgmt/ardor/grs24.html 

NIST SP 800-30, Risk Management Guide for 

Information Technology Systems

http://csrc.nist.gov/publications/nistpubs/800-30/sp800-30.pdf 

NIST SP 800-32, Introduction to Public Key 

Technology and the Federal PKI Infrastructure

http://csrc.nist.gov/publications/nistpubs/800-32/sp800-32.pdf

NIST SP 800-48 Revision 1, Guide to Securing 

Legacy IEEE 802.11 Wireless Networks 

http://csrc.nist.gov/publications/nistpubs/800-48-rev1/SP800-

48r1.pdf 

NIST SP 800-50, Building an Information 

Technology Security Awareness and Training 

Program

http://csrc.nist.gov/publications/nistpubs/800-50/NIST-SP800-

50.pdf 

NIST SP 800-53 Revision 2, Recommended 

Security Controls for Federal Information Systems

http://csrc.nist.gov/publications/nistpubs/800-53-Rev2/sp800-

53-rev2-final.pdf 

NIST SP 800-63, Electronic Authentication 

Guideline

http://csrc.nist.gov/publications/nistpubs/800-63/SP800-

63V1_0_2.pdf 

NIST SP 800-63-1 (Draft), Electronic 

Authentication Guideline 

http://csrc.nist.gov/publications/PubsSPs.html 

NIST SP 800-64, Security Considerations in the 

Information System Development Life Cycle

http://csrc.nist.gov/publications/nistpubs/800-64/NIST-SP800-

64.pdf 

NIST SP 800-70, Security Configuration Checklists 

Program for IT Products – Guidance for Checklists 

Users and Developers

http://checklists.nist.gov/docs/SP_800-70_20050526.pdf 

NIST SP 800-111, Guide to Storage Encryption 

Technologies for End User Devices

http://csrc.nist.gov/publications/nistpubs/800-111/SP800-

111.pdf 

NIST SP 800-114, User's Guide to Securing 

External Devices for Telework and Remote Access

http://csrc.nist.gov/publications/nistpubs/800-114/SP800-

114.pdf 

D-1 
GUIDE TO BLUETOOTH SECURITY

Resource Sites 

Name URL 

Bluetooth Special Interest Group http://www.bluetooth.com/

http://www.bluetooth.org/

Cellular Telecommunications and Internet Association (CTIA) http://www.ctia.org/

Federal Communications Commission http://www.fcc.gov/

FIPS-Validated Cryptographic Modules http://csrc.nist.gov/groups/STM/index.html

IEEE 802.15 Working Group for Wireless Personal Area Networks http://www.ieee802.org/15/

NIST National Vulnerability Database (NVD) http://nvd.nist.gov/

NIST’s National Checklist Program http://checklists.nist.gov/ 

Trifinite Group (Bluetooth Security Research) http://www.trifinite.org/ 

Wireless Vulnerabilities and Exploits http://www.wirelessve.org/

 

D-2