Special Publication 800-145

The NIST Definition of Cloud
Computing
Recommendations of the National Instituteof Standards and Technology
Peter Mell
Timothy Grance

NIST Special Publication 800-145

The NIST Definition of Cloud ComputingPeter Mell
Timothy Grance

C O M P U T E R

S E C U R I T Y

Computer Security Division
Information Technology Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899-8930
September 2011

U.S. Department of Commerce

Rebecca M. Blank, Acting Secretary
National Institute of Standards and Technology

Patrick D. Gallagher, Under Secretary for Standards andTechnology and Director

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’smeasurement and standards infrastructure. ITL develops tests, test methods, reference data, proof ofconcept implementations, and technical analysis to advance the development and productive use ofinformation technology. ITL’s responsibilities include the development of technical, physical,administrative, and management standards and guidelines for the cost-effective security and privacy ofsensitive 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.
National Institute of Standards and Technology Special Publication 800-145
7 pages (September 2011)

Certain commercial entities, equipment, or materials may be identified in thisdocument in order to describe an experimental procedure or concept adequately.
Such identification is not intended to imply recommendation or endorsement by theNational Institute of Standards and Technology, nor is it intended to imply that theentities, materials, or equipment are necessarily the best available for the purpose.

iiAcknowledgements

The authors Peter Mell and Timothy Grance of the National Institute of Standards and Technology(NIST) would like to thank the many experts in industry and government who contributed their thoughts
to the creation and review of this definition. We especially acknowledge Murugiah Souppaya and Lee
Badger, also of NIST, and Wayne Jansen of Booz Allen Hamilton, whose advice and technical insightassisted this effort.

ErrataThe following changes have been incorporated into Special Publication 800-145, as of the date indicatedin the table.
DATE
4/27/2012TYPE
Editorial

CHANGE
Corrected page number from “2” to “1”iii

PAGE NUMBER
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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, forproviding adequate information security for all agency operations and assets; but such standards andguidelines shall not apply to national security systems. This guideline is consistent with the requirementsof 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 nongovernmentalorganizations on a voluntary basis and is not subject to copyright, though attribution is desired.
Nothing in this document should be taken to contradict standards and guidelines made mandatory andbinding on Federal agencies by the Secretary of Commerce under statutory authority, nor should theseguidelines 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

Cloud computing is an evolving paradigm. The NIST definition characterizes important aspects of cloudcomputing and is intended to serve as a means for broad comparisons of cloud services and deployment
strategies, and to provide a baseline for discussion from what is cloud computing to how to best use cloudcomputing. The service and deployment models defined form a simple taxonomy that is not intended toprescribe or constrain any particular method of deployment, service delivery, or business operation.
1.3

Audience

The intended audience of this document is system planners, program managers, technologists, and others
adopting cloud computing as consumers or providers of cloud services.

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2.

The NIST Definition of Cloud Computing

Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a sharedpool of configurable computing resources (e.g., networks, servers, storage, applications, and services) thatcan be rapidly provisioned and released with minimal management effort or service provider interaction.
This cloud model is composed of five essential characteristics, three service models, and four deploymentmodels.
Essential Characteristics:
On-demand self-service. A consumer can unilaterally provision computing capabilities, such asserver time and network storage, as needed automatically without requiring humaninteraction with each service provider.
Broad network access. Capabilities are available over the network and accessed through standard
mechanisms that promote use by heterogeneous thin or thick client platforms (e.g.,mobile phones, tablets, laptops, and workstations).
Resource pooling. The provider’s computing resources are pooled to serve multiple consumers
using a multi-tenant model, with different physical and virtual resources dynamicallyassigned and reassigned according to consumer demand. There is a sense of location
independence in that the customer generally has no control or knowledge over the exact
location of the provided resources but may be able to specify location at a higher level ofabstraction (e.g., country, state, or datacenter). Examples of resources include storage,
processing, memory, and network bandwidth.
Rapid elasticity. Capabilities can be elastically provisioned and released, in some cases
automatically, to scale rapidly outward and inward commensurate with demand. To theconsumer, the capabilities available for provisioning often appear to be unlimited and canbe appropriated in any quantity at any time.
Measured service. Cloud systems automatically control and optimize resource use by leveraging
a metering capability1 at some level of abstraction appropriate to the type of service (e.g.,storage, processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported, providing transparency for both the provider andconsumer of the utilized service.
Service Models:
Software as a Service (SaaS). The capability provided to the consumer is to use the provider’sapplications running on a cloud infrastructure 2. The applications are accessible fromvarious client devices through either a thin client interface, such as a web browser (e.g.,web-based email), or a program interface. The consumer does not manage or control theunderlying cloud infrastructure including network, servers, operating systems, storage, oreven individual application capabilities, with the possible exception of limited userspecific application configuration settings.
Platform as a Service (PaaS). The capability provided to the consumer is to deploy onto the cloudinfrastructure consumer-created or acquired applications created using programming

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Typically this is done on a pay-per-use or charge-per-use basis.
A cloud infrastructure is the collection of hardware and software that enables the five essential characteristics of cloudcomputing. The cloud infrastructure can be viewed as containing both a physical layer and an abstraction layer. The physicallayer consists of the hardware resources that are necessary to support the cloud services being provided, and typically includes
server, storage and network components. The abstraction layer consists of the software deployed across the physical layer,
which manifests the essential cloud characteristics. Conceptually the abstraction layer sits above the physical layer.

2languages, libraries, services, and tools supported by the provider.3 The consumer does
not manage or control the underlying cloud infrastructure including network, servers,
operating systems, or storage, but has control over the deployed applications and possibly
configuration settings for the application-hosting environment.
Infrastructure as a Service (IaaS). The capability provided to the consumer is to provision
processing, storage, networks, and other fundamental computing resources where theconsumer is able to deploy and run arbitrary software, which can include operating
systems and applications. The consumer does not manage or control the underlying cloudinfrastructure but has control over operating systems, storage, and deployed applications;and possibly limited control of select networking components (e.g., host firewalls).
Deployment Models:Private cloud. The cloud infrastructure is provisioned for exclusive use by a single organization
comprising multiple consumers (e.g., business units). It may be owned, managed, andoperated by the organization, a third party, or some combination of them, and it may exist
on or off premises.
Community cloud. The cloud infrastructure is provisioned for exclusive use by a specificcommunity of consumers from organizations that have shared concerns (e.g., mission,
security requirements, policy, and compliance considerations). It may be owned,managed, and operated by one or more of the organizations in the community, a thirdparty, or some combination of them, and it may exist on or off premises.
Public cloud. The cloud infrastructure is provisioned for open use by the general public. It may be
owned, managed, and operated by a business, academic, or government organization, orsome combination of them. It exists on the premises of the cloud provider.
Hybrid cloud. The cloud infrastructure is a composition of two or more distinct cloudinfrastructures (private, community, or public) that remain unique entities, but are boundtogether by standardized or proprietary technology that enables data and application
portability (e.g., cloud bursting for load balancing between clouds).

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This capability does not necessarily preclude the use of compatible programming languages, libraries, services, and tools fromother sources.

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