AUTHENTICATED CHANNEL FOR ENCRYPTION MANAGEMENT

This disclosure provides systems, methods and apparatuses for managing encryption in a network. A local modem is managed by a local control processor (CP) via a local authenticated channel. The local authenticated channel is established between the local modem and a first CP (as the local CP) using runtime authentication material. When the first CP is removed or becomes inoperative, the local modem detects an authentication failure associated with the local authenticated channel. The local modem can communicate an alarm message via a trusted channel to a remote modem. In response to the alarm message, the local modem can receive a reauthentication command via the trusted channel. The reauthentication command is configured to cause the local modem to establish a new local authenticated channel with a second CP (such as a new local CP to replace the first CP).

TECHNICAL FIELD

This disclosure relates generally to network communication and some aspects relate to maintaining an authenticated channel for managing encryption in a network.

DESCRIPTION OF RELATED TECHNOLOGY

In a communication system, two or more network devices can communicate encrypted data via a transport network (such as an optical transport network (OTN) or wide area network). The links of the transport network might include cables or wireless signals (including links that traverse public networks, shared networks, wireless networks, or point-to-point network connections) that connect the network devices with one another. The network devices can implement security protocols to protect data communicated via a link. Each network device can have one or more modems that serve as endpoints of respective links. Two modems (sometimes referred to as encryption modems) can establish an encrypted traffic channel over a link. The modems use data path encryption to encrypt and decrypt data communicated via the encrypted traffic channel. The modems can also establish a trusted channel over the link to communicate encryption settings (such as keys, cipher settings, and the like). The trusted channel is used for key agreement or other encryption settings so that a receiver of encrypted data can properly decrypt the encrypted traffic channel. The trusted channel can also be used to coordinate a security association between the encryption modems.

In some implementations, encryption modems are managed by control processors (CPs). A CP can initialize and manage cryptographic functions of a modem. Where two modems serve as respective endpoints of a link, the modems can be managed by a different respective CPs. For example, the first modem and a first CP at one endpoint of a link can be referred to as a local modem and local CP, respectively. The second modem and a second CP at another endpoint of a link can be referred to as a remote modem and a remote CP, respectively. Each CP provides encryption parameters that the corresponding modem uses to secure the trusted channel, the encrypted traffic channel, or both. Examples of encryption parameters can include peer authentication material for establishing the trusted channel, cryptography key material for encryption or decryption of the encrypted traffic channel, and security policies, among other examples.

A CP provides encryption parameters to a corresponding modem via an authenticated channel between the CP and the modem. When the modem has an authenticated channel with a CP, the modem is said to be in a managed state. Conversely, when the modem does not have an authenticated channel with a CP, the modem is said to be in an unmanaged state. The authenticated channel can become unavailable when the CP is removed, damaged, blocked or otherwise inaccessible. If a modem remains in an unmanaged state, the modem may be unable to perform some cryptographic functions associated with data path encryption.

BRIEF SUMMARY

The systems, methods, and apparatuses of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

One aspect of this disclosure can be implemented as a local modem. The local modem includes a management interface, a link interface, and a modem processor. The link interface is configured to communicatively couple the local modem to a remote modem. The modem processor is configured to establish a local authenticated channel with a first control processor (CP) via the management interface. The modem processor is configured to manage a trusted channel between the local modem and the remote modem via the link interface based on encryption parameters received from the first CP. The modem processor is configured to detect that the first CP has become unavailable and communicate an alarm message via the trusted channel based on the first CP becoming unavailable. The modem processor is configured to receive a reauthentication command via the trusted channel. The modem processor is configured to reestablish the local authenticated channel with a second CP via the management interface based on the reauthentication command.

Another aspect of this disclosure can be implemented as a method of a local modem. The method includes establishing a local authenticated channel with a first control processor (CP) via a management interface of the local modem and managing a trusted channel over a link interface communicatively coupling the local modem to a remote modem based on encryption parameters received from the first CP. The method includes detecting that the first CP has become unavailable and communicating an alarm message via the trusted channel based on the first CP becoming unavailable. The method includes receiving a reauthentication command via the trusted channel. The method includes reestablishing the local authenticated channel with a second CP via the management interface based on the reauthentication command.

Another aspect of this disclosure can be implemented in a CP. The CP includes a management interface having a local authenticated channel to a local modem. The control also includes a processor configured to provide encryption parameters to the local modem via the local authenticated channel to enable the local modem to manage a trusted channel between the local modem and a remote modem. The CP is configured to receive an alarm message from the local modem via the local authenticated channel, where the alarm message indicates that the remote modem is in an unmanaged state due to failure of a remote authenticated channel between the remote modem and a first remote CP. The CP is configured to communicate a reauthentication command to the remote modem via the local authenticated channel, the local modem, and the trusted channel. The reauthentication command is configured to cause the remote modem to reestablish the remote authenticated channel with a second remote CP.

Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims.

DETAILED DESCRIPTION

The following description is directed to certain implementations for the purpose of describing innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations can be implemented in any means, apparatus, system, or method for network communication.

Two network devices communicate via a link. A first network device (which may be referred to as a local network device) includes a local modem at one endpoint of the link. A second network device (which may be referred to as a remote network device) includes a remote modem at another endpoint of the link. The local modem and the remote modem can communicate encrypted data via an encrypted traffic channel over the link. To manage the encrypted traffic channel, the local modem and the remote modem can also establish a trusted channel over the link. In addition to the trusted channel, each modem can have an authenticated channel to a corresponding control processor (CP). Each CP provides encryption parameters (such as peer authentication material for the trusted channel, key material associated with the encrypted traffic channel, or security policies, among other examples) to its corresponding modem. This disclosure distinguishes the various modems, authentication channels and CPs by referring to a local system and a remote system. The designation of “local” and “remote” is for clarity of the description. Using this nomenclature, a local modem has a local authenticated channel with a local CP, and a remote modem has a remote authenticated channel with a remote CP.

A local authenticated channel between a local CP and a local modem is secured by authentication material. In some implementations, local CP and the local modem initially authenticate each other using default authentication material (such as pre-programmed certificates). After the initial authentication, the local CP and the local modem can share runtime authentication material (which may include runtime certificates). The runtime authentication material can be specific to the local CP or can be unique for the local authenticated channel between them. After sharing runtime authentication material, the local CP and the local modem use the runtime authentication material to establish and maintain the local authenticated channel.

Occasionally, a local CP might be removed or replaced, such as due to servicing or “hot-swapping” the CP associated with the local system. When a new CP is introduced, the local modem may not have runtime authentication material for the new CP. Therefore, the local modem may be unable to authenticate the new CP and the local authenticated channel may no longer be available. When a local modem does not have a local authentication channel to a CP, the local modem is said to be in an unmanaged state. In the unmanaged state, the local modem may continue to maintain the trusted channel with the remote modem for a period of time. However, if the local modem remains in the unmanaged state beyond the period of time, the local modem may be unable to continue encrypted communication with the remote modem.

This disclosure provides systems, methods and apparatuses for managing encryption in a network. The disclosed techniques enable a local modem to manage a local authenticated channel between the local modem and a local CP. The local CP is configured to manage encryption parameters of the local modem for encryption of data between the local modem and a remote modem. The local authenticated channel is initially established between the local modem and a first CP (as the local CP). When the first CP becomes unavailable, the local modem detects an authentication failure due to the runtime authentication material for the first CP no longer being effective. As a result, the local authenticated channel becomes unavailable and the local modem enters an unmanaged state. The local modem can communicate an alarm message via a trusted channel to the remote modem. In response to the alarm message, the local modem can receive a reauthentication command via the trusted channel. The reauthentication command is configured to cause the local modem to authenticate a second CP and establish a new local authenticated channel with the second CP. For example, the second CP may be a new local CP to replace the first CP.

In some aspects, the reauthentication command can include runtime authentication material associated with the second CP such that the local modem can identify and authenticate the second CP. The local modem can use the runtime authentication material from the reauthentication command to establish the new local authenticated channel with the second CP. The runtime authentication material for the second CP may be configured by a user at the remote system or may be securely obtained from a network management server.

In some aspects, the reauthentication command may not explicitly identify the second CP or may not include the runtime authentication material for the second CP. In such instances, the reauthentication command may trigger the local modem to authenticate the second CP using default authentication material. After the local modem authenticates the second CP using the default authentication material, the local modem and the second CP can share runtime authentication material and establish the new local authenticated channel.

In some aspects, the sequence of operations including the alarm message, the reauthentication command, and the authentication of the second CP can collectively be referred to as a reauthentication protocol. The reauthentication protocol might include other operations. For example, the reauthentication protocol may include communication between the remote modem and a remote CP in relation to the reauthentication command. The reauthentication protocol can include operations by the local modem to determine whether the reauthentication command is valid or to determine when to disregard the reauthentication command based on one or more conditions. For example, the local modem may disregard the reauthentication command if the local modem already has established a new local authenticated channel with another CP or if the reauthentication command is received after a time limit following the alarm message.

Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. The disclosed techniques can enable a first CP to be replaced (also referred to as being “hot-swapped”) by a second CP with little or no disruption to the encryption functions of the first modem. Thus, a user can perform field servicing of a CP while a modem remains active. The reauthentication protocol can reduce complexity and time associated with managing authenticated channels between modems and their respective CPs. Furthermore, the disclosed techniques include protections against identity replacement attacks or other security breaches that might otherwise occur during a reauthentication procedure.

FIG.1illustrates an example communication system100. The communication system100includes a first network device110and a second network device130. The first network device110includes a modem (labeled as local modem120) configured to communicate with the second network device130. The second network device130includes a modem (labeled as remote modem140). The local modem120and the remote modem140are endpoints of a link150between the first network device110and the second network device130. The link150may be a fiber optic connection between the local modem120and the remote modem140. The local modem120and the remote modem140are managed by CPs.FIG.1shows a first CP115(acting as a local CP) configured to manage the local modem120.FIG.2also shows a remote CP135configured to manage the remote modem140. In some implementations, the CPs115and135are collocated or integrated into the network devices110and130, as shown inFIG.1. For example, the CPs can be modules of the network devices. In some other implementations, the one or both of the CPs may be external components that are communicatively coupled to the network devices. InFIG.1, the first CP115and the local modem120may be referred to as a local system, and the remote CP135and the remote modem140may be referred to as a remote system.

In some implementations, the first network device110may include an encryption module116. The encryption module116may include the local modem120and one or more other modems124. Similarly, the second network device130may include an encryption module136that includes the remote modem140and one or more other modems144. In some examples, the network devices110and130may be rack mounted hardware platforms. The rack mounted hardware platforms may include a chassis in which the encryption modules116and136can be placed and communicatively coupled. Similarly, the CPs115and135may be hot-swappable components within the network devices110and130.

In some communication systems, a key management service180can distribute cryptographic keys, authentication material, security policies, or other configurations to the first CP115and the remote CP135. In addition to, or in lieu of, the key management service180, the communication system might include a network management server (not shown) configured to coordinate security policies of the first CP115and the remote CP135. The key management service180(or network management server) can communicate security parameters to the first CP115via a first northbound interface182and can communicate security parameters to the remote CP135via a second northbound interface184. The term “northbound interface” refers to a relationship in which the key management service180has a higher level management authority over the CPs115and135compared to the level of management between the CPs115and135and their corresponding modems120and140.

FIG.1shows some aspects of the local system for descriptive purposes. The local modem120has an authenticated channel (referred to as a local authenticated channel122) with the first CP115. The local authenticated channel122can also be referred to as a cryptography management channel or a north-south (N/S) channel. The local authenticated channel122may be established over an untrusted network, such as a local network internally located within the first network device110. In some implementations, the local authenticated channel122is established using Transport Layer Security (TLS) 1.3 protocols. TLS includes authentication as well as encryption of information between devices. Alternatively, or additionally, the local modem120and the first CP115could use other security protocols that include authentication. Authentication refers to a security process to verify that a device is who it claims to be. Authorization refers to a security process to determine level of access. Authentication and authorization are closely related and sometimes referred to collectively as “authentication” in a security protocol if authorization is assumed for properly authenticated devices. Some security protocols (such as TLS) can include procedures for both authentication and encryption. Network security, including continual authentication of network channels, enables protection against intrusion, eavesdropping, and circumvention.

As described previously, the local authenticated channel122may be authenticated by authentication material. In some implementations, the local modem120initially authenticates the first CP115using default authentication material. The default authentication material can also be referred to as an initial device identification (“iDevID”). In some implementations, the default authentication material may be a pre-determined global certificate shared by one or more manufactures of CPs that are compatible with the local modem120. The local modem120can use a trust on first use (TOFU) mechanism to select a CP. InFIG.1, the local modem120detects that the first CP115is present in the local system based on an initial authentication of the default authentication material. After the initial authentication, the first CP115and the local modem120establish mutual authentication material referred to as runtime authentication material. The runtime authentication material can be referred to as a logical device identification (“LDevID”). Additionally, or alternatively, the runtime authentication material can be referred to as a CP identification (CPID). The runtime authentication material may include device identification certificates. For example, the local modem120can store a device identification certificate of the first CP115and the first CP115can store a device identification certificate of the local modem120. The runtime authentication material of the first CP115may be referred to as a first CP identification (CPID1).

The first CP115and the local modem120store the runtime authentication material in volatile memory and use the runtime authentication material to maintain authentication of the local authenticated channel122. Once the local modem120establishes the local authenticated channel122with the first CP115, the local modem120latches to the runtime authentication material of the first CP115to mitigate the potential security risk of another CP attempting to manage the local modem120.

The first CP115provides encryption parameters to the local modem120via the local authenticated channel122. The local modem120uses the encryption parameters to establish a trusted channel152with the remote modem140via the link150. The trusted channel can also be referred to as a peer encryption management channel or an east-west (E/W) channel because it coordinates security policies between peer modems having the same or similar security level. The local modem120also establishes an encrypted traffic channel154over the link150. The trusted channel152is used for key agreement between the local modem120and the remote modem140for encryption and decryption of traffic in the encrypted traffic channel154. In some implementations, the trusted channel152and the encrypted traffic channel154can be established using the TLS 1.3 protocol. Once the trusted channel152and the encrypted traffic channel154are established, the local modem120can encrypt and communicate traffic from first network node(s)160to remote modem140. Thus, traffic originating from first network node(s)160and destined for second network node(s)170can be encrypted and communicated via the encrypted traffic channel154. Similarly, the local modem120can receive encrypted traffic destined for the first network node(s)160via the encrypted traffic channel154.

Having described the local system (including operations of the local modem120, the local authenticated channel122and the first CP115), it should be understood that the remote system performs similar operations. The remote modem140has a remote authenticated channel142with the remote CP135that is authenticated using runtime authentication material that is specific to the remote CP135and the remote modem140. The remote modem140is a peer endpoint of the trusted channel152and the encrypted traffic channel154with the local modem120.

FIG.2illustrates an example use case in which a CP is replaced. Occasionally, a CP may require maintenance or replacement. In the example ofFIG.2, the first CP115may be removed from the first network device110for servicing. The first CP115may be replaced by a second CP215. When the first CP115is removed or offline, the local authenticated channel122becomes unavailable and the local modem120enters an unmanaged state. Because the local modem120is latched to the runtime authentication material (CPID1) of the first CP115, the local modem120will not automatically reauthenticate with the second CP215.

The local modem120can continue to communicate with the remote modem140via the trusted channel152in the unmanaged state. However, after a period of time in the unmanaged state, the encryption parameters may become stale and the absence of the local authenticated channel122can cause a disruption in the encrypted traffic channel154. One technique to cause the local modem120to reestablish a local authenticated channel222with the second CP215is to power cycle the local modem120. Power cycling the local modem120causes it to detect a second CP215based on the TOFU mechanism using the default authentication material. Power cycling the local modem120causes a disruption in the encrypted traffic channel154. Therefore, some aspects of this disclosure describe a reauthentication protocol that enables the local modem120to reestablish a local authenticated channel222with the second CP215without disrupting the encrypted traffic channel154.

In accordance with aspects of this disclosure, when the local modem120detects that the local authenticated channel122is unavailable (or when the local modem120detects that it has entered an unmanaged state), the local modem120communicates an alarm message to the remote modem140. In various examples, the alarm message can indicate a loss of communication with the first CP115, a failure to authenticate the first CP115via the local authenticated channel122, an indication that the first CP115has been replaced by the second CP215, or a status indicating that the local modem120is in the unmanaged state.

The remote modem140can relay the alarm message to the remote CP135. The remote CP135can communicate a reauthentication command to the local modem120(via the remote modem140and the trusted channel152) to cause the local modem120to reestablish the local authenticated channel222with the second CP215. Before communicating the reauthentication command, the remote CP135may obtain a verification from a higher level authority (such as from a user or a network management server). In some implementations, when the remote CP135receives the alarm message, the remote CP135communicates an error message to the user or the network management server to indicate that the remote CP135. Alternatively, the remote CP135can cause an error message to appear on a user interface (not shown). In response to the error message, the remote CP135may receive an instruction from the user, network management server, or user interface, where the instruction causes the remote CP135to communicate the reauthentication command to the local modem120. In some implementations, the remote CP135may obtain runtime authentication material of the second CP215from a user or network management server and include the runtime authentication material of the second CP215in the reauthentication command.

In some implementations, the reauthentication command is configured to cause the local modem120to detect any available CP using the TOFU mechanism and the default authentication material. For example, the reauthentication command may not explicitly indicate or identify the second CP215. Rather, the reauthentication command may trigger the local modem120to discover the second CP215. After discovering the second CP215, the local modem120reestablishes the local authenticated channel222with the second CP215.

In some other implementations, the reauthentication command is configured to cause the local modem120to reauthenticate the second CP215. The second CP215may be identified or otherwise indicated in the reauthentication command. For example, the reauthentication command can include runtime authentication material associated with the second CP215. The runtime authentication material of the second CP215may be referred to as a second CP identification (CPID2). The local modem120may use the CPID2 to authenticate the second CP215and maintain the local authenticated channel222with the second CP215.

After receiving the reauthentication command, the local modem120authenticates the second CP215and reestablishes the local authenticated channel (shown as local authenticated channel222) with the second CP215. In some implementations, the local modem120can determine whether to follow or disregard the reauthentication command based on one or more conditions, such as those described with reference toFIG.7. For example, if the local modem120already has established a new local authenticated channel with another CP, the local modem120may disregard the reauthentication command. Alternatively, or additionally, if the local modem120receives the reauthentication command after a time limit following communication of the alarm message, the local modem120may disregard the reauthentication command.

FIG.3illustrates a message flow diagram300in accordance with some aspects of this disclosure. The message flow diagram300shows operations and messages of the local modem120, the remote modem140and remote CP135. At the beginning of the message flow diagram300, the local modem120and the first CP115have established a local authenticated channel302. Similarly, the remote modem140and the remote CP135have established a remote authenticated channel304. The local modem120receives encryption parameters from the first CP115via the local authenticated channel302. The remote modem140receives encryption parameters from the remote CP135via the remote authenticated channel304. Using the encryption parameters, the local modem120and the remote modem140establish a trusted channel306.

At some time (shown as event308), the first CP115is removed or becomes offline. The local modem120detects310that the local authenticated channel302is no longer available based on a failure to communicate with the first CP115. The local modem120communicates an alarm message312to the remote modem140, which provides the alarm message312to the remote CP135. At process314, the remote CP135determines to generate a reauthentication command316based on user input or verification from a network management server. The remote CP135communicates the reauthentication command316to the remote modem140, which relays the reauthentication command316to the local modem120via the trusted channel306. After receiving the reauthentication command316via the trusted channel306, the local modem120performs a reauthentication318to establish a local authenticated channel320with the second CP215.

FIG.4illustrates an example alarm message402according to some implementations of this disclosure. The alarm message402may be communicated from a local modem (such as the local modem120described with reference toFIG.2andFIG.3) via a trusted channel (such as the trusted channel306described with reference toFIG.3) to a remote modem (such as the remote modem140described with reference toFIG.2andFIG.3). The alarm message402might include one or more fields, information elements, or indicators. For example, the alarm message402might indicate a loss of communication with local CP404, a failure to authenticate the first CP via the local authenticated channel406, an indication that the first CP has been replaced by the second CP410, a status indicating that the local modem being in an unmanaged state412, or any combination thereof.

FIG.5illustrates an example reauthentication command502according to some implementations of this disclosure. The reauthentication command502may be communicated from a remote modem (such as the remote modem140described with reference toFIG.2andFIG.3) via a trusted channel (such as the trusted channel306described with reference toFIG.3) to a local modem (such as the local modem120described with reference toFIG.2andFIG.3). The reauthentication command502might include one or more fields, information elements, or indicators. For example, the reauthentication command502might include an instruction to reauthenticate with a new local CP504(such as the second CP215described with reference toFIG.2andFIG.3), runtime authentication material506for the new local CP, a public certificate508of the new local CP, a certificate chain510associated with the new local CP, or any combination thereof.

FIG.6illustrates example operations600of a modem according to some implementations of this disclosure. The example operations600might be performed by a local modem (such as the local modem120described with reference toFIG.2andFIG.3). In block602, the local modem establishes a local authenticated channel with a first CP via a management interface of the local modem. In block604, the local modem manages a trusted channel over a link interface communicatively coupling the local modem to a remote modem based on encryption parameters received from the first CP. In block606, the local modem detects that the first CP has become unavailable. In block608, the local modem communicates an alarm message via the trusted channel based on the first CP becoming unavailable. In block610, the local modem receives a reauthentication command via the trusted channel. In block612, the local modem reestablishes the local authenticated channel with a second CP via the management interface based on the reauthentication command.

FIG.7illustrates example operations700to increase security of a reauthentication protocol according to some implementations of this disclosure. The example operations700might be performed by a local modem (such as the local modem120described with reference toFIG.2andFIG.3). At block710, the local modem receives a reauthentication command via a trusted channel. The local modem may determine whether to process the reauthentication command or disregard the reauthentication command based on one or more conditions (shown as a first example condition705aand a second example condition705binFIG.7). While both the first example condition705aand second example condition705bare shown together inFIG.7, it should be understood that a local modem can use one condition (either of the example conditions705aand705b). Furthermore, the local modem can use the example conditions705aand705bin a different order than illustrated inFIG.7.

In the first example condition705a, at block720, the local modem determines whether it has an existing local authenticated channel with any other CP. For example, the local modem may have already reauthenticated with another CP before receiving the reauthentication command. This condition also prevents the local modem from acting on the reauthentication command when the local modem is already in a managed state and is latched to an existing CP of the local system. A potential technical advantage of the first example condition705ais that the local modem can mitigate against an identity replacement attack in which an attacker injects a spoofed reauthentication command into the trusted channel in attempt to breach the security of the local system. In block720, if the local modem already has an existing local authenticated channel, the local modem proceeds to block750where the local modem disregards the reauthentication command. Alternatively, if the local modem does not already have an existing local authenticated channel, the local modem may proceed to another condition (such as the second example condition705b) or to block740where the local modem processes the reauthentication command.

In the second example condition705b, at block730, the local modem determines whether the reassociation command was received within a time limit following communication of an alarm message. A potential technical advantage of the second example condition705bis that the local modem can mitigate the risk of prolonged exposure to an identity replacement attack during the reauthentication protocol. In block730, if the reauthentication command is received after the time limit, the local modem proceeds to block750where the local modem disregards the reauthentication command. Alternatively, if the reauthentication command is received before expiration of the time limit, the local modem may proceed to another condition (not shown) or to block740where the local modem processes the reauthentication command.

Although the time limit described with reference to block730is based on the duration between communication of the alarm message and reception of a reauthentication command, other time limits can be implemented to limit prolonged exposure. For example, in implementations where the local modem decides to process the reauthentication command in block740, the local modem may implement a time limit regarding how long the local modem will attempt to authenticate a new CP, as described in the following paragraph.

At block740, the local modem authenticates with a second CP and reestablishes the local authenticated channel with the second CP based on the reauthentication command. In some implementations, the operations of block740are initiated by the second CP. For example, the second CP may initiate establishment of the local authenticated channel using runtime authentication material of the second CP by initiating a TLS handshake. When the runtime authentication material presented in the TLS handshake matches runtime authentication material obtained from the reauthentication command and the TLS handshake occurs within a time period following the reauthentication command, the local modem completes the TLS handshake to establish the local authenticated channel with the second CP.

Alternatively, the reauthentication command may not include runtime authentication material for any CP but instead instructs the local modem to authenticate with the next CP that initiates a TLS handshake using default authentication material. If the TLS handshake is initiated by the second CP within the time period following the reauthentication command, the local modem may complete the TLS handshake and obtain the runtime authentication material of the second CP directly from the second CP. Once the second modem has obtained the runtime authentication material, the second modem can use the runtime authentication material to establish the local authenticated channel.

At block750, if any of the conditions (such as the example conditions705aand705b) are met, the local modem disregards the reauthentication command.

FIG.8illustrates example operations800of a control processor according to some implementations of this disclosure. The example operations800might be performed by a remote CP (such as the remote CP135described with reference toFIG.2andFIG.3). At block802, the remote CP establishes a remote authenticated channel between the remote CP and a remote modem. At block804, the remote CP provides encryption parameters to the remote modem via the remote authenticated channel to enable the remote modem to manage a trusted channel between the remote modem and a local modem. At block806, the remote CP receives an alarm message from the remote modem via the remote authenticated channel. The alarm message indicates that the local modem is in an unmanaged state due to failure of a local authenticated channel between the local modem and a first local CP. At block808, the remote CP communicates a reauthentication command to the local modem via the remote authenticated channel, the remote modem, and the trusted channel. The reauthentication command is configured to cause the local modem to reestablish the local authenticated channel with a second local CP.

Although the example operations600,700, and800described with reference toFIG.6,FIG.7, andFIG.8, respectively, depict a particular sequence of operations, the sequence may be altered without departing from the scope of the present disclosure. For example, some of the operations depicted may be performed in parallel or in a different sequence that does not materially affect the function of the operations. In other examples, different components of an example device or system that implements the operations may perform functions at substantially the same time or in a specific sequence.

FIG.9Aillustrates a block diagram900aof an example CP915according to some implementations of this disclosure. The CP915may be an example of any of the control processors described herein, such as the first CP115, the remote CP135, or the second CP215described with reference toFIG.1,FIG.2, andFIG.3. The CP915may be capable of performing any of the operations described with reference to the first CP115, the remote CP135, or the second CP215, or any of the example operations800described with reference toFIG.8.

The CP915includes a management interface916, a processor917, a memory918, and a northbound interface919. The management interface916is configured to communicate with a modem and serves as an endpoint of an authenticated channel. The processor917can communicate encryption parameters to the modem via the management interface916and the authenticated channel. In some aspects, the memory918stores the encryption parameters. Additionally, or alternatively, the memory918stores runtime authentication material for the modem. The processor917can manage the management interface916to establish the authenticated channel using the runtime authentication material obtained from the memory918. The northbound interface919can communicate with a key management service or a network management server. Alternatively, or additionally, the northbound interface919can provide a communication interface for user commands.

FIG.9Billustrates a block diagram900bof an example modem920according to some implementations of this disclosure. The modem920may be an example of any of the modems described herein, such as the local modem120or the remote modem140described with reference toFIG.1,FIG.2, andFIG.3. The modem920may be capable of performing any of the operations described with reference to the local modem120or the remote modem140, or any of the example operations600and700described with reference toFIG.6andFIG.8, respectively.

The modem920includes a management interface922, a modem processor924, a memory926, a client interface928, a data path encryption unit930, and a line interface932. The management interface922is configured to communicate with a CP and serves as an endpoint of an authenticated channel. The modem processor924can receive encryption parameters from the CP via the management interface922and the authenticated channel. In some aspects, the memory926stores the encryption parameters. Additionally, or alternatively, the memory926stores runtime authentication material for the CP. The modem processor924can manage the management interface922to establish the authenticated channel using the runtime authentication material obtained from the memory926. In accordance with aspects of this disclosure the modem processor924can reestablish a local authenticated channel with a new CP based on a reauthentication command received from a remote modem or remote CP.

The modem processor924also manages cryptography functions of the data path encryption unit930based on encryption parameters received from the CP. The data path encryption unit930encrypts traffic received from network nodes via the client interface928and communicates the encrypted traffic via the line interface932to a remote modem. The line interface932can serve as an endpoint of a link to the remote modem. The line interface932is configured to establish a trusted channel and an encrypted traffic channel over the link. In some implementations, the client interface928is a wired network interface, such as any of the communication technologies described in Institute of Electrical and Electronics Engineers (IEEE) 802.3 family of standards. In some implementations, the line interface932is an optical interface. The data path encryption unit930may include an encryption processor for line speed encryption of traffic from the client interface928to the line interface932and line speed decryption of traffic from the line interface932to the client interface928.

With reference toFIG.9AandFIG.9B, various implementations of processors, interfaces, and memory are possible. Either, or both, the processor917or the modem processor924may include multiple processors, multiple cores or multiple nodes. The processor917or the modem processor924may implement multi-tasking and multi-threading, among other examples. The processor917or the modem processor924can be any custom made or commercially available processor, a central processing unit (CPU), general purpose processor (GPP), multicore processor, an auxiliary processor among several processors, a semiconductor-based microprocessor (in the form of a microchip or chipset), or generally any device for executing software instructions. The memory (such as memory918and/or memory926) may be system memory or any one or more of the possible realizations of computer-readable media described herein. The memory can include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatile memory elements (e.g., ROM, hard drive, flash drive, solid state drive (SSD), CDROM, etc.), and combinations thereof. Moreover, the memory may incorporate electronic, magnetic, optical, and/or other types of storage media.

The interfaces (such as management interface916, the northbound interface919, the management interface922, the client interface928, the line interface932) and the memory (such as memory918or memory926) may be communicatively coupled to one another and to the processor (such as processor917or924), for example, by a bus (not shown). The bus can be any type of bus, including buses such as PCI, ISA, PCI-Express, HyperTransport®, InfiniBand®, NuBus®, AHB, AXI, etc. In some implementations, the interfaces may be distributed within the processor and the memory. The memory may include computer instructions executable by the processor to implement the functionality of the implementations described herein. Any one of these functionalities may be partially, or entirely, implemented in hardware or on the processor. For example, the functionality may be implemented with an application specific integrated circuit, in logic implemented in the processor, in a co-processor on a peripheral device or card, among other examples. Further, realizations may include fewer or additional components not illustrated inFIG.9AandFIG.9B.

FIG.1throughFIG.9Band the operations described herein are examples meant to aid in understanding example implementations and should not be used to limit the potential implementations or limit the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some operations differently.

As used herein, a phrase referring to “at least one of” or “one or more of” a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

As described above, some aspects of the subject matter described in this specification can be implemented as software. For example, various functions of components disclosed herein, or various blocks or steps of a method, operation, process or algorithm disclosed herein can be implemented as one or more modules of one or more computer programs. Such computer programs can include non-transitory processor-executable or computer-executable instructions encoded on one or more tangible processor-readable or computer-readable storage media for execution by, or to control the operation of, a data processing apparatus including the components of the devices described herein. By way of example, and not limitation, such storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in consideration of the above disclosure or may be acquired from practice of the aspects. While the aspects of the disclosure have been described in terms of various examples, any combination of aspects from any of the examples is also within the scope of the disclosure. The examples in this disclosure are provided for pedagogical purposes. Alternatively, or in addition to the other examples described herein, examples include any combination of the disclosed implementation options.