Internet Engineering Task Force (IETF)                       G. Lebovitz
Request for Comments: 6518                                     M. Bhatia
Category: Informational                                   Alcatel-Lucent
ISSN: 2070-1721                                            February 2012
Internet Engineering Task Force (IETF)                       G. Lebovitz
Request for Comments: 6518                                     M. Bhatia
Category: Informational                                   Alcatel-Lucent
ISSN: 2070-1721                                            February 2012

Keying and Authentication for Routing Protocols (KARP) Design Guidelines




This document is one of a series concerned with defining a roadmap of protocol specification work for the use of modern cryptographic mechanisms and algorithms for message authentication in routing protocols. In particular, it defines the framework for a key management protocol that may be used to create and manage session keys for message authentication and integrity.


Status of This Memo


This document is not an Internet Standards Track specification; it is published for informational purposes.


This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.

本文件是互联网工程任务组(IETF)的产品。它代表了IETF社区的共识。它已经接受了公众审查,并已被互联网工程指导小组(IESG)批准出版。并非IESG批准的所有文件都适用于任何级别的互联网标准;见RFC 5741第2节。

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at


Copyright Notice


Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved.

版权所有(c)2012 IETF信托基金和确定为文件作者的人员。版权所有。

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents ( in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(自本文件出版之日起生效。请仔细阅读这些文件,因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本,并提供简化BSD许可证中所述的无担保。

Table of Contents


   1. Introduction ....................................................3
      1.1. Conventions Used in This Document ..........................4
   2. Categorizing Routing Protocols ..................................5
      2.1. Category: Message Transaction Type .........................5
      2.2. Category: Peer versus Group Keying .........................6
   3. Consider the Future Existence of a Key Management Protocol ......6
      3.1. Consider Asymmetric Keys ...................................7
      3.2. Cryptographic Keys Life Cycle ..............................8
   4. Roadmap .........................................................9
      4.1. Work Phases on Any Particular Protocol .....................9
      4.2. Work Items per Routing Protocol ...........................11
   5. Routing Protocols in Categories ................................13
   6. Supporting Incremental Deployment ..............................16
   7. Denial-of-Service Attacks ......................................17
   8. Gap Analysis ...................................................18
   9. Security Considerations ........................................20
      9.1. Use Strong Keys ...........................................21
      9.2. Internal versus External Operation ........................22
      9.3. Unique versus Shared Keys .................................22
      9.4. Key Exchange Mechanism ....................................24
   10. Acknowledgments ...............................................26
   11. References ....................................................26
       11.1. Normative References ....................................26
       11.2. Informative References ..................................26
   1. Introduction ....................................................3
      1.1. Conventions Used in This Document ..........................4
   2. Categorizing Routing Protocols ..................................5
      2.1. Category: Message Transaction Type .........................5
      2.2. Category: Peer versus Group Keying .........................6
   3. Consider the Future Existence of a Key Management Protocol ......6
      3.1. Consider Asymmetric Keys ...................................7
      3.2. Cryptographic Keys Life Cycle ..............................8
   4. Roadmap .........................................................9
      4.1. Work Phases on Any Particular Protocol .....................9
      4.2. Work Items per Routing Protocol ...........................11
   5. Routing Protocols in Categories ................................13
   6. Supporting Incremental Deployment ..............................16
   7. Denial-of-Service Attacks ......................................17
   8. Gap Analysis ...................................................18
   9. Security Considerations ........................................20
      9.1. Use Strong Keys ...........................................21
      9.2. Internal versus External Operation ........................22
      9.3. Unique versus Shared Keys .................................22
      9.4. Key Exchange Mechanism ....................................24
   10. Acknowledgments ...............................................26
   11. References ....................................................26
       11.1. Normative References ....................................26
       11.2. Informative References ..................................26
1. Introduction
1. 介绍

In March 2006, the Internet Architecture Board (IAB) held a workshop on the topic of "Unwanted Internet Traffic". The report from that workshop is documented in RFC 4948 [RFC4948]. Section 8.1 of that document states that "A simple risk analysis would suggest that an ideal attack target of minimal cost but maximal disruption is the core routing infrastructure". Section 8.2 calls for "[t]ightening the security of the core routing infrastructure". Four main steps were identified for that tightening:

2006年3月,互联网架构委员会(IAB)举办了一次关于“不必要的互联网流量”主题的研讨会。该研讨会的报告记录在RFC 4948[RFC4948]中。该文件第8.1节指出,“简单的风险分析表明,成本最低但中断最大的理想攻击目标是核心路由基础设施”。第8.2节要求“加强核心路由基础设施的安全性”。确定了拧紧的四个主要步骤:

o Increase the security mechanisms and practices for operating routers.

o 增加操作路由器的安全机制和实践。

o Clean up the Internet Routing Registry [IRR] repository, and securing both the database and the access, so that it can be used for routing verifications.

o 清理Internet路由注册表[IRR]存储库,并确保数据库和访问的安全,以便将其用于路由验证。

o Create specifications for cryptographic validation of routing message content.

o 为路由消息内容的加密验证创建规范。

o Secure the routing protocols' packets on the wire.

o 在线路上保护路由协议的数据包。

The first bullet is being addressed in the OPSEC working group. The second bullet should be addressed through liaisons with those running the IRR's globally. The third bullet is being addressed in the SIDR working group.


This document addresses the last bullet, securing the packets on the wire of the routing protocol exchanges. Thus, it is concerned with guidelines for describing issues and techniques for protecting the messages between directly communicating peers. This may overlap with, but is strongly distinct from, protection designed to ensure that routing information is properly authorized relative to sources of this information. Such authorizations are provided by other mechanisms and are outside the scope of this document and the work that relies on it.


This document uses the terminology "on the wire" to talk about the information used by routing systems. This term is widely used in RFCs, but is used in several different ways. In this document, it is used to refer both to information exchanged between routing protocol instances and to underlying protocols that may also need to be protected in specific circumstances. Other documents that will analyze individual protocols will need to indicate how they use the term "on the wire".


The term "routing transport" is used to refer to the layer that exchanges the routing protocols. This can be TCP, UDP, or even direct link-level messaging in the case of some routing protocols. The term is used here to allow a referent for discussing both common and disparate issues that affect or interact with this dimension of the routing systems. The term is used here to refer generally to the set of mechanisms and exchanges underneath the routing protocol, whatever that is in specific cases.


Keying and Authentication for Routing Protocols (KARP) will focus on an abstraction for keying information that describes the interface between routing protocols, operators, and automated key management. Conceptually, when routing protocols send or receive messages, they will look up the key to use in this abstract key table. Conceptually, there will be an interface for a routing protocol to make requests of automated key management when it is being used; when keys become available, they will be made available in the key table. There is no requirement that this abstraction be used for implementation; the abstraction serves the needs of standardization and management. Specifically, as part of the KARP work plan:


1) KARP will design the key table abstraction, the interface between key management protocols and routing protocols, and possibly security protocols at other layers.

1) KARP将设计密钥表抽象、密钥管理协议和路由协议之间的接口,以及可能的其他层的安全协议。

2) For each routing protocol, KARP will define the mapping between how the protocol represents key material and the protocol-independent key table abstraction. When routing protocols share a common mechanism for authentication, such as the TCP Authentication Option, the same mapping is likely to be reused between protocols. An implementation may be able to move much of the keying logic into code related to this shared authentication primitive rather than code specific to routing protocols.

2) 对于每个路由协议,KARP将定义协议如何表示关键材料和独立于协议的关键表抽象之间的映射。当路由协议共享一个通用的身份验证机制(如TCP身份验证选项)时,可能会在协议之间重用相同的映射。一个实现可能能够将大部分键控逻辑移动到与此共享身份验证原语相关的代码中,而不是特定于路由协议的代码中。

3) When designing automated key management for both symmetric keys and group keys, we will only use the abstractions designed in point 1 above to communicate between automated key management and routing protocols.

3) 在为对称密钥和组密钥设计自动密钥管理时,我们将只使用上面第1点中设计的抽象来在自动密钥管理和路由协议之间进行通信。

Readers must refer to [THTS-REQS] for a clear definition of the scope, goals, non-goals, and the audience for the design work being undertaken in the KARP WG.


1.1. Conventions Used in This Document
1.1. 本文件中使用的公约

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

本文件中的关键词“必须”、“不得”、“要求”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照RFC 2119[RFC2119]中所述进行解释。

2. Categorizing Routing Protocols
2. 路由协议分类

This document places the routing protocols into two categories according to their requirements for authentication. We hope these categories will allow design teams to focus on security mechanisms for a given category. Further, we hope that each protocol in the group will be able to reuse the authentication mechanism. It is also hoped that, down the road, we can create one Key Management Protocol (KMP) per category (if not for several categories), so that the work can be easily leveraged for use in the various routing protocol groupings. KMPs are useful for allowing simple, automated updates of the traffic keys used in a base protocol. KMPs replace the need for humans, or operational support systems (OSS) routines, to periodically replace keys on running systems. It also removes the need for a chain of manual keys to be chosen or configured on such systems. When configured properly, a KMP will enforce the key freshness policy among peers by keeping track of the key's lifetime and negotiating a new key at the defined interval.


2.1. Category: Message Transaction Type
2.1. 类别:消息事务类型

The first category defines three types of messaging transactions used on the wire by the base routing protocol. They are as follows:




One peer router directly and intentionally delivers a route update specifically to one other peer router. Examples are BGP [RFC4271]; LDP [RFC5036]; BFD [RFC5880]; and RSVP-TE [RFC3209], [RFC3473], [RFC4726], and [RFC5151]. Point-to-point modes of both IS-IS [RFC1195] and OSPF [RFC2328], when sent over both traditional point-to-point links and when using multi-access layers, may both also fall into this category.




A router peers with multiple other routers on a single network segment -- i.e., on link local -- such that it creates and sends one route update message that is intended for multiple peers. Examples would be OSPF and IS-IS in their broadcast, non-point-to-point mode and Routing Information Protocol (RIP) [RFC2453].




Multicast protocols have unique security properties because they are inherently group-based protocols; thus, they have group keying requirements at the routing level where link-local


routing messages are multicasted. Also, at least in the case of Protocol Independent Multicast - Sparse Mode (PIM-SM) [RFC4601], some messages are sent unicast to a given peer(s), as is the case with router-close-to-sender and the "Rendezvous Point". Some work for application-layer message security has been done in the Multicast Security (MSEC) working group and may be helpful to review, but it is not directly applicable.


These categories affect both the routing protocol view of the communication and the actual message transfer. As a result, some message transaction types for a few routing protocols may be mixtures, for example, using broadcast where multicast might be expected or using unicast to deliver what looks to the routing protocol like broadcast or multicast.


Protocol security analysis documents produced in the KARP working group need to pay attention both to the semantics of the communication and the techniques that are used for the message exchanges.


2.2. Category: Peer versus Group Keying
2.2. 类别:对等键控与组键控

The second category is the keying mechanism that will be used to distribute the session keys to the routing transports. They are as follows:


Peer Keying


One router sends the keying messages only to one other router, such that a one-to-one, uniquely keyed security association (SA) is established between the two routers (e.g., BGP, BFD and LDP).


Group Keying


One router creates and distributes a single keying message to multiple peers. In this case, a group SA will be established and used among multiple peers simultaneously. Group keying exists for protocols like OSPF [RFC2328] and for multicast protocols like PIM-SM [RFC4601].


3. Consider the Future Existence of a Key Management Protocol
3. 考虑密钥管理协议的未来存在

When it comes time for the KARP WG to design a reusable model for a Key Management Protocol (KMP), [RFC4107] should be consulted.


When conducting the design work on a manually keyed version of a routing protocol's authentication mechanism, consideration must be made for the eventual use of a KMP. In particular, design teams must consider what parameters would need to be handed to the routing protocols by a KMP.


Examples of parameters that might need to be passed are as follows: a security association identifier (e.g., IPsec Security Parameter Index (SPI) or the TCP Authentication Option's (TCP-AO's) KeyID), a key lifetime (which may be represented in either bytes or seconds), the cryptographic algorithms being used, the keys themselves, and the directionality of the keys (i.e., receiving versus the sending keys).


3.1. Consider Asymmetric Keys
3.1. 考虑非对称密钥

The use of asymmetric keys can be a very powerful way to authenticate machine peers as used in routing protocol peer exchanges. If generated on the machine, and never moved off the machine, these keys will not need to be changed if an administrator leaves the organization. Since the keys are random, they are far less susceptible to off-line dictionary and guessing attacks.


An easy and simple way to use asymmetric keys is to start by having the router generate a public/private key pair. At the time of this writing, the recommended key size for algorithms based on integer factorization cryptography like RSA is 1024 bits and 2048 bits for extremely valuable keys like the root key pair used by a certification authority. It is believed that a 1024-bit RSA key is equivalent in strength to 80-bit symmetric keys and 2048-bit RSA keys to 112-bit symmetric keys [RFC3766]. Elliptic Curve Cryptography (ECC) [RFC4492] appears to be secure with shorter keys than those needed by other asymmetric key algorithms. National Institute of Standards and Technology (NIST) guidelines [NIST-800-57] state that ECC keys should be twice the length of equivalent strength symmetric key algorithms. Thus, a 224-bit ECC key would roughly have the same strength as a 112-bit symmetric key.


Many routers have the ability to be remotely managed using Secure Shell (SSH) Protocol [RFC4252] and [RFC4253]. As such, routers will also have the ability to generate and store an asymmetric key pair, because this is the common authentication method employed by SSH when an administrator connects to a router for management sessions.

许多路由器都能够使用Secure Shell(SSH)协议[RFC4252]和[RFC4253]进行远程管理。因此,路由器还能够生成和存储非对称密钥对,因为这是SSH在管理员连接到路由器进行管理会话时使用的常用身份验证方法。

Once an asymmetric key pair is generated, the KMP generating security association parameters and keys for routing protocol may use the machine's asymmetric keys for the authentication mechanism. The form of the identity proof could be raw keys, the more easily administrable self-signed certificate format, or a PKI-issued [RFC5280] certificate credential.


Regardless of which credential is standardized, the authentication mechanism can be as simple as a strong hash over a string of human-readable and transferable form of ASCII characters. More complex, but also more secure, the identity proof could be verified through the use of a PKI system's revocation checking mechanism, (e.g., Certificate Revocation List (CRL) or Online Certificate Status Protocol (OCSP) responder). If the SHA-1 fingerprint is used, the solution could be as simple as loading a set of neighbor routers' peer ID strings into a table and listing the associated fingerprint string for each ID string. In most organizations or peering points, this list will not be longer than a thousand or so routers, and often the list will be much shorter. In other words, the entire list for a given organization's router ID and hash could be held in a router's configuration file, uploaded, downloaded, and moved about at will. Additionally, it doesn't matter who sees or gains access to these fingerprints, because they can be distributed publicly as it needn't be kept secret.


3.2. Cryptographic Keys Life Cycle
3.2. 密钥生命周期

Cryptographic keys should have a limited lifetime and may need to be changed when an operator who had access to them leaves. Using a key chain, a set of keys derived from the same keying material and used one after the other, also does not help as one still has to change all the keys in the key chain when an operator having access to all those keys leaves the company. Additionally, key chains will not help if the routing transport subsystem does not support rolling over to the new keys without bouncing the routing sessions and adjacencies. So the first step is to fix the routing stack so that routing protocols can change keys without breaking or bouncing the adjacencies.


An often cited reason for limiting the lifetime of a key is to minimize the damage from a compromised key. It could be argued that it is likely a user will not discover an attacker has compromised the key if the attacker remains "passive"; thus, relatively frequent key changes will limit any potential damage from compromised keys.


Another threat against the long-lived key is that one of the systems storing the key, or one of the users entrusted with the key, will be subverted. So, while there may not be cryptographic motivations of changing the keys, there could be system security motivations for rolling the key.


Although manual key distribution methods are subject to human error and frailty, more frequent manual key changes might actually increase the risk of exposure, as it is during the time that the keys are being changed that they are likely to be disclosed. In these cases, especially when very strong cryptography is employed, it may be more prudent to have fewer, well-controlled manual key distributions rather than more frequent, poorly controlled manual key distributions. In general, where strong cryptography is employed, physical, procedural, and logical access protection considerations often have more impact on the key life than do algorithm and key size factors.


For incremental deployments, we could start by associating life times with the send and the receive keys in the key chain for the long-lived keys. This is an incremental approach that we could use until the cryptographic keying material for individual sessions is derived from the keying material stored in a database of long-lived cryptographic keys as described in [CRPT-TAB]. A key derivation function (KDF) and its inputs are also specified in the database of long-lived cryptographic keys; session-specific values based on the routing protocol are input to the KDF. Protocol-specific key identifiers may be assigned to the cryptographic keying material for individual sessions if needed.


The long-lived cryptographic keys used by the routing protocols can either be inserted manually in a database or make use of an automated key management protocol to do this.


4. Roadmap
4. 路线图
4.1. Work Phases on Any Particular Protocol
4.1. 任何特定协议的工作阶段

It is believed that improving security for any routing protocol will be a two-phase process. The first phase would be to modify routing protocols to support modern cryptography algorithms and key agility. The second phase would be to design and move to an automated key management mechanism. This is like a crawl, walk, and run process. In order for operators to accept these phases, we believe that the key management protocol should be clearly separated from the routing transport. This would mean that the routing transport subsystem is oblivious to how the keys are derived, exchanged, and downloaded as long as there is something that it can use. It is like having a


routing-protocol-configuration switch that requests the security module for the "KARP security parameters" so that it can refer to some module written, maintained, and operated by security experts and insert those parameters in the routing exchange.


The desired end state for the KARP work contains several items. First, the people desiring to deploy securely authenticated and integrity validated packets between routing peers have the tools specified, implemented, and shipped in order to deploy. These tools should be fairly simple to implement and not more complex than the security mechanisms to which the operators are already accustomed. (Examples of security mechanisms to which router operators are accustomed include: the use of asymmetric keys for authentication in SSH for router configuration, the use of pre-shared keys (PSKs) in TCP MD5 for BGP protection, the use of self-signed certificates for HTTP Secure (HTTPS) access to device Web-based user interfaces, the use of strongly constructed passwords and/or identity tokens for user identification when logging into routers and management systems.) While the tools that we intend to specify may not be able to stop a deployment from using "foobar" as an input key for every device across their entire routing domain, we intend to make a solid, modern security system that is not too much more difficult than that. In other words, simplicity and deployability are keys to success. The routing protocols will specify modern cryptographic algorithms and security mechanisms. Routing peers will be able to employ unique, pair-wise keys per peering instance, with reasonable key lifetimes, and updating those keys on a regular basis will be operationally easy, causing no service interruption.

KARP工作所需的结束状态包含多个项目。首先,希望在路由对等点之间部署经过安全认证和完整性验证的数据包的人,已经指定、实现和发布了用于部署的工具。这些工具的实现应该相当简单,并且不会比操作员已经习惯的安全机制更复杂。(路由器操作员习惯的安全机制示例包括:在SSH中使用非对称密钥进行身份验证以进行路由器配置,在TCP MD5中使用预共享密钥(PSK)进行BGP保护,在HTTP安全(HTTPS)中使用自签名证书。)访问基于Web的设备用户界面,在登录路由器和管理系统时使用强构造密码和/或身份令牌进行用户标识。)而我们打算指定的工具可能无法阻止部署使用“foobar”作为每个设备在其整个路由域中的输入密钥,我们打算建立一个可靠的、现代化的安全系统,这不会比这更困难。换句话说,简单性和可部署性是成功的关键。路由协议将指定现代密码算法和安全机制。路由对等方将能够在每个对等实例中使用唯一的、成对的密钥,具有合理的密钥生命周期,并且定期更新这些密钥在操作上很容易,不会造成服务中断。

Achieving the above described end state using manual keys may be pragmatic only in very small deployments. However, manual keying in larger deployments will be too burdensome for operators. Thus, the second goal is to support key life cycle management with a KMP. We expect that both manual and automated key management will coexist in the real world.


In accordance with the desired end state just described, we define two main work phases for each routing protocol:


1. Enhance the routing protocol's current authentication mechanism(s). This work involves enhancing a routing protocol's current security mechanisms in order to achieve a consistent, modern level of security functionality within its existing key management framework. It is understood and accepted that the existing key management frameworks are largely based on manual keys. Since many operators have already built operational support systems (OSS) around these manual key implementations, there is some automation available for an operator to leverage in

1. 增强路由协议的当前身份验证机制。这项工作涉及增强路由协议的当前安全机制,以便在其现有密钥管理框架内实现一致的现代安全功能。人们理解并接受,现有的密钥管理框架主要基于手动密钥。由于许多运营商已经围绕这些手动键实现构建了运营支持系统(OSS),因此运营商可以利用一些自动化

that way, if the underlying mechanisms are themselves secure. In this phase, we explicitly exclude embedding or creating a KMP. Refer to [THTS-REQS] for the list of the requirements for Phase 1 work.


2. Develop an automated key management framework. The second phase will focus on the development of an automated keying framework to facilitate unique pair-wise (group-wise, where applicable) keys per peering instance. This involves the use of a KMP. The use of automatic key management mechanisms offers a number of benefits over manual keying. Most important, it provides fresh traffic keying material for each session, thus helping to prevent inter-connection replay attacks. In an inter-connection replay attack, protocol packets from the earlier protocol session are replayed affecting the current execution of the protocol. A KMP is also helpful because it negotiates unique, pair-wise, random keys, without administrator involvement. It negotiates several SA parameters like algorithms, modes, and parameters required for the secure connection, thus providing interoperability between endpoints with disparate capabilities and configurations. In addition it could also include negotiating the key lifetimes. The KMP can thus keep track of those lifetimes using counters and can negotiate new keys and parameters before they expire, again, without administrator interaction. Additionally, in the event of a breach, changing the KMP key will immediately cause a rekey to occur for the traffic key, and those new traffic keys will be installed and used in the current connection. In summary, a KMP provides a protected channel between the peers through which they can negotiate and pass important data required to exchange proof of identities, derive traffic keys, determine rekeying, synchronize their keying state, signal various keying events, notify with error messages, etc.

2. 开发一个自动化的密钥管理框架。第二阶段的重点是开发一个自动键控框架,以便为每个对等实例提供唯一的成对(分组,如适用)键。这涉及使用KMP。使用自动密钥管理机制比手动密钥管理有许多好处。最重要的是,它为每个会话提供了新的流量键控材料,从而有助于防止连接间重播攻击。在连接间重播攻击中,重播来自先前协议会话的协议数据包,从而影响协议的当前执行。KMP也很有用,因为它可以在没有管理员参与的情况下协商唯一的、成对的随机密钥。它协商几个SA参数,如安全连接所需的算法、模式和参数,从而提供具有不同功能和配置的端点之间的互操作性。此外,它还可以包括协商关键生命周期。因此,KMP可以使用计数器跟踪这些生命周期,并可以在新密钥和参数过期之前协商它们,而无需管理员交互。此外,如果出现违规情况,更改KMP密钥将立即导致交通密钥的重新密钥,并且这些新交通密钥将在当前连接中安装和使用。总之,KMP在对等方之间提供了一个受保护的通道,通过该通道,对等方可以协商和传递交换身份证明、派生流量密钥、确定密钥更新、同步其密钥更新状态、向各种密钥更新事件发信号、用错误消息通知等所需的重要数据。

4.2. Work Items per Routing Protocol
4.2. 每个路由协议的工作项

Each routing protocol will have a team (the Routing_Protocol-KARP team, e.g., the OSPF-KARP team) working on incrementally improving the security of a routing protocol. These teams will have the following main work items:




Characterize the Routing Protocol


Assess the routing protocol to see what authentication and integrity mechanisms it has today. Does it need significant improvement to its existing mechanisms or not? This will


include determining if modern, strong security algorithms and parameters are present and if the protocol supports key agility without bouncing adjacencies.


Define Optimal State


List the requirements for the routing protocol's session key usage and format to contain modern, strong security algorithms and mechanisms, per the Requirements document [THTS-REQS]. The goal here is to determine what is needed for the routing protocol to be used securely with at least manual key management.


Gap Analysis


Enumerate the requirements for this protocol to move from its current security state, the first bullet, to its optimal state, as listed just above.


Transition and Deployment Considerations


Document the operational transition plan for moving from the old to the new security mechanism. Will adjacencies need to bounce? What new elements/servers/services in the infrastructure will be required? What is an example work flow that an operator will take? The best possible case is if the adjacency does not break, but this may not always be possible.


Define, Assign, Design


Create a deliverables list of the design and specification work, with milestones. Define owners. Release one or more documents.




KMP Analysis


Review requirements for KMPs. Identify any nuances for this particular routing protocol's needs and its use cases for a KMP. List the requirements that this routing protocol has for being able to be used in conjunction with a KMP. Define the optimal state and check how easily it can be decoupled from the KMP.


Gap Analysis


Enumerate the requirements for this protocol to move from its current security state to its optimal state, with respect to the key management.


Define, Assign, Design


Create a deliverables list of the design and specification work, with milestones. Define owners. Generate the design and document work for a KMP to be able to generate the routing protocol's session keys for the packets on the wire. These will be the arguments passed in the API to the KMP in order to bootstrap the session keys for the routing protocol.


There will also be a team formed to work on the base framework mechanisms for each of the main categories.


5. Routing Protocols in Categories
5. 类别中的路由协议

This section groups the routing protocols into categories according to attributes set forth in the Categories' Section (Section 2). Each group will have a design team tasked with improving the security of the routing protocol mechanisms and defining the KMP requirements for their group, then rolling both into a roadmap document upon which they will execute.




These routing protocols fall into the category of the one-to-one peering messages and will use peer keying protocols. Border Gateway Protocol (BGP) [RFC4271], Path Computation Element Communication Protocol (PCEP) [RFC5440], and Multicast Source Discovery Protocol (MSDP) [RFC3618] messages are transmitted over TCP, while Label Distribution Protocol (LDP) [RFC5036] uses both UDP and TCP. A team will work on one mechanism to cover these TCP unicast protocols. Much of the work on the routing protocol update for its existing authentication mechanism has already occurred in the TCPM working group, on the TCP-AO [RFC5925] document, as well as its cryptography-helper document, TCP-AO-CRYPTO [RFC5926]. However, TCP-AO cannot be used for discovery exchanges carried in LDP as those are carried over UDP. A separate team might want to look at LDP. Another exception is the mode where LDP is used directly on the LAN. The work for this may go into the group keying category (along with OSPF) as mentioned below.




The routing protocols that fall into the category group keying (with one-to-many peering) includes OSPF [RFC2328], IS-IS [RFC1195] and RIP [RFC2453]. Not surprisingly, all these routing protocols have two other things in common. First, they are run on a combination of the OSI datalink Layer 2, and the OSI network Layer 3. By this we mean that they have a component of how the routing protocol works, which is specified in Layer 2 as well as in Layer 3. Second, they are all internal gateway protocols (IGPs). The keying mechanisms will be much more complicated to define for these than for a one-to-one messaging protocol.




Because it is less of a routing protocol, per se, and more of a peer liveness detection mechanism, Bidirectional Forwarding Detection (BFD) [RFC5880] will have its own team. BFD is also different from the other protocols covered here as it works on millisecond timers and would need separate considerations to mitigate the potential for Denial-of-Service (DoS) attacks. It also raises interesting issues [RFC6039] with respect to the sequence number scheme that is generally deployed to protect against replay attacks as this space can roll over quite frequently because of the rate at which BFD packets are generated.




The Resource reSerVation Protocol (RSVP) [RFC2205] allows hop-by-hop authentication of RSVP neighbors, as specified in [RFC2747]. In this mode, an integrity object is attached to each RSVP message to transmit a keyed message digest. This message digest allows the recipient to verify the identity of the RSVP node that sent the message and to validate the integrity of the message. Through the inclusion of a sequence number in the scope of the digest, the digest also offers replay protection.


[RFC2747] does not dictate how the key for the integrity operation is derived. Currently, most implementations of RSVP use a statically configured key, on a per-interface or per-neighbor basis.


RSVP relies on a per-peer authentication mechanism where each hop authenticates its neighbor using a shared key or a certificate.


Trust in this model is transitive. Each RSVP node trusts, explicitly, only its RSVP next-hop peers through the message digest contained in the INTEGRITY object [RFC2747]. The next-hop


RSVP speaker, in turn, trusts its own peers, and so on. See also the document "RSVP Security Properties" [RFC4230] for more background.


The keys used for protecting the RSVP messages can be group keys (for example, distributed via the Group Domain of Interpretation (GDOI) [RFC6407], as discussed in [GDOI-MAC]).


The trust an RSVP node has with another RSVP node has an explicit and implicit component. Explicitly, the node trusts the other node to maintain the integrity (and, optionally, the confidentiality) of RSVP messages depending on whether authentication or encryption (or both) are used. This means that the message has not been altered or its contents seen by another, non-trusted node. Implicitly, each node trusts the other node to maintain the level of protection specified within that security domain. Note that in any group key management scheme, like GDOI, each node trusts all the other members of the group with regard to data origin authentication.


RSVP-TE [RFC3209], [RFC3473], [RFC4726], and [RFC5151] is an extension of the RSVP protocol for traffic engineering. It supports the reservation of resources across an IP network and is used for establishing MPLS label switch paths (LSPs), taking into consideration network constraint parameters such as available bandwidth and explicit hops. RSVP-TE signaling is used to establish both intra- and inter-domain TE LSPs.

RSVP-TE[RFC3209]、[RFC3473]、[RFC4726]和[RFC5151]是用于流量工程的RSVP协议的扩展。它支持在IP网络上保留资源,并用于建立MPLS标签交换路径(LSP),同时考虑可用带宽和显式跳数等网络约束参数。RSVP-TE信令用于建立域内和域间TE LSP。

When signaling an inter-domain RSVP-TE LSP, operators may make use of the security features already defined for RSVP-TE [RFC3209]. This may require some coordination between domains to share keys ([RFC2747][RFC3097]), and care is required to ensure that the keys are changed sufficiently frequently. Note that this may involve additional synchronization, should the domain border nodes be protected with Fast Reroute, since the merge point (MP) and point of local repair (PLR) should also share the key.

当向域间RSVP-TE LSP发送信号时,运营商可以利用已经为RSVP-TE定义的安全特性[RFC3209]。这可能需要域之间进行一些协调以共享密钥([RFC2747][RFC3097]),并且需要注意确保密钥的更改足够频繁。注意,如果域边界节点通过快速重路由得到保护,这可能涉及额外的同步,因为合并点(MP)和本地修复点(PLR)也应该共享密钥。

For inter-domain signaling for MPLS-TE, the administrators of neighboring domains must satisfy themselves as to the existence of a suitable trust relationship between the domains. In the absence of such a relationship, the administrators should decide not to deploy inter-domain signaling and should disable RSVP-TE on any inter-domain interfaces.


KARP will currently be working only on RSVP-TE, as the native RSVP lies outside the scope of the WG charter.




Finally, the multicast protocols Protocol Independent Multicast - Sparse Mode (PIM-SM) [RFC4601] and Protocol Independent Multicast - Dense Mode (PIM-DM) [RFC3973] will be grouped together. PIM-SM multicasts routing information (Hello, Join/Prune, Assert) on a link-local basis, using a defined multicast address. In addition, it specifies unicast communication for exchange of information (Register, Register-Stop) between the router closest to a group sender and the "Rendezvous Point". The Rendezvous Point is typically not "on-link" for a particular router. While much work has been done on multicast security for application-layer groups, little has been done to address the problem of managing hundreds or thousands of small one-to-many groups with link-local scope. Such an authentication mechanism should be considered along with the router-to-Rendezvous Point authentication mechanism. The most important issue is ensuring that only the "authorized neighbors" get the keys for source/group (S,G), so that rogue routers cannot participate in the exchanges. Another issue is that some of the communication may occur intra-domain, e.g., the link-local messages in an enterprise, while others for the same (*,G) may occur inter-domain, e.g., the router-to-Rendezvous Point messages may be from one enterprise's router to another.


One possible solution proposes a region-wide "master" key server (possibly replicated), and one "local" key server per speaking router. There is no issue with propagating the messages outside the link, because link-local messages, by definition, are not forwarded. This solution is offered only as an example of how work may progress; further discussion should occur in this work team. Specification of a link-local protection mechanism for PIM-SM is defined in [RFC4601], and this mechanism has been updated in PIM-SM-LINKLOCAL [RFC5796]. However, the KMP part is completely unspecified and will require work outside the expertise of the PIM working group to accomplish, another example of why this roadmap is being created.


6. Supporting Incremental Deployment
6. 支持增量部署

It is imperative that the new authentication and security mechanisms defined support incremental deployment, as it is not feasible to deploy a new routing protocol authentication mechanism throughout the network instantaneously. One of the goals of the KARP WG is to add incremental security to existing mechanisms rather than replacing them. Delivering better deployable solutions to which vendors and operators can migrate is more important than getting a perfect security solution. It may also not be possible to deploy such a mechanism to all routers in a large Autonomous System (AS) at one


time. This means that the designers must work on this aspect of the authentication mechanism for the routing protocol on which they are working. The mechanisms must provide backward compatibility in the message formatting, transmission, and processing of routing information carried through a mixed security environment.


7. Denial-of-Service Attacks
7. 拒绝服务攻击

DoS attacks must be kept in mind when designing KARP solutions. [THTS-REQS] describes DoS attacks that are in scope for the KARP work. Protocol designers should ensure that the new cryptographic validation mechanisms must not provide an attacker with an opportunity for DoS attacks. Cryptographic validation, while typically cheaper than signing, is still an incremental cost. If an attacker can force a system to validate many packets multiple times, then this could be a potential DoS attack vector. On the other hand, if the authentication procedure is itself quite CPU intensive, then overwhelming the CPU with multiple bogus packets can bring down the system. In this case, the authentication procedure itself aids the DoS attack.


There are some known techniques to reduce the cryptographic computation load. Packets can include non-cryptographic consistency checks. For example, [RFC5082] provides a mechanism that uses the IP header to limit the attackers that can inject packets that will be subject to cryptographic validation. In the design, Phase 2, once an automated key management protocol is developed, it may be possible to determine the peer IP addresses that are valid participants. Only the packets from the verified sources could be subject to cryptographic validation.


Protocol designers must ensure that a device never needs to check incoming protocol packets using multiple keys, as this can overwhelm the CPU, leading to a DoS attack. KARP solutions should indicate the checks that are appropriate prior to performing cryptographic validation. KARP solutions should indicate where information about valid neighbors can be used to limit the scope of the attacks.


Particular care needs to be paid to the design of automated key management schemes. It is often desirable to force a party attempting to authenticate to do work and to maintain state until that work is done. That is, the initiator of the authentication should maintain the cost of any state required by the authentication for as long as possible. This also helps when an attacker sends an overwhelming load of keying protocol initiations from bogus sources.


Another important class of attack is denial of service against the routing protocol where an attacker can manipulate either the routing protocol or the cryptographic authentication mechanism to disrupt routing adjacencies.


Without KARP solutions, many routing protocols are subject to disruption simply by injecting an invalid packet or a packet for the wrong state. Even with cryptographic validation, replay attacks are often a vector where a previously valid packet can be injected to create a denial of service. KARP solutions should prevent all cases where packet replays or other packet injections by an outsider can disrupt routing sessions.


Some residual denial-of-service risk is always likely. If an attacker can generate a large enough number of packets, the routing protocol can get disrupted. Even if the routing protocol is not disrupted, the loss rate on a link may rise to a point where claiming that traffic can successfully be routed across the link will be inaccurate.


8. Gap Analysis
8. 差距分析

The [THTS-REQS] document lists the generic requirements for the security mechanisms that must exist for the various routing protocols that come under the purview of KARP. There will be different design teams working for each of the categories of routing protocols defined.


To start, design teams must review the "Threats and Requirements for Authentication of routing protocols" document [THTS-REQS]. This document contains detailed descriptions of the threat analysis for routing protocol authentication and integrity in general. Note that it does not contain all the authentication-related threats for any one routing protocol, or category of routing protocols. The design team must conduct a protocol-specific threat analysis to determine if threats beyond those in the [THTS-REQS] document arise in the context of the protocol (group) and to describe those threats.


The [THTS-REQS] document also contains many security requirements. Each routing protocol design team must walk through each section of the requirements and determine one by one how its protocol either does or does not relate to each requirement.


Examples include modern, strong, cryptographic algorithms, with at least one such algorithm listed as a MUST, algorithm agility, secure use of simple PSKs, intra-connection replay protection, inter-connection replay protection, etc.


When doing the gap analysis, we must first identify the elements of each routing protocol that we wish to protect. In case of protocols riding on top of IP, we might want to protect the IP header and the protocol headers, while for those that work on top of TCP, it will be the TCP header and the protocol payload. There is patently value in protecting the IP header and the TCP header if the routing protocols rely on these headers for some information (for example, identifying the neighbor that originated the packet).


Then, there will be a set of cryptography requirements that we might want to look at. For example, there must be at least one set of cryptographic algorithms (MD5, SHA, etc.) or constructions (Hashed MAC (HMAC), etc.) whose use is supported by all implementations and can be safely assumed to be supported by any implementation of the authentication option. The design teams should look for the protocol on which they are working. If such algorithms or constructions are not available, then some should be defined to support interoperability by having a single default.


Design teams must ensure that the default cryptographic algorithms and constructions supported by the routing protocols are accepted by the community. This means that the protocols must not rely on non-standard or ad hoc hash functions, keyed-hash constructions, signature schemes, or other functions, and they must use published and standard schemes.


Care should also be taken to ensure that the routing protocol authentication scheme has algorithm agility (i.e., it is capable of supporting algorithms other than its defaults). Ideally, the authentication mechanism should not be affected by packet loss and reordering.


Design teams should ensure that their protocol's authentication mechanism is able to accommodate rekeying. This is essential since it is well known that keys must periodically be changed. Also, what the designers must ensure is that this rekeying event should not affect the functioning of the routing protocol. For example, OSPF rekeying requires coordination among the adjacent routers, while IS-IS requires coordination among routers in the entire domain.


If new authentication and security mechanisms are needed, then the design teams must design in such a manner that the routing protocol authentication mechanism remains oblivious to how the keying material is derived. This decouples the authentication mechanism from the key management system that is employed.


Design teams should also note that many routing protocols require prioritized treatment of certain protocol packets and authentication mechanisms should honor this.


Not all routing protocol authentication mechanisms provide support for replay attacks, and the design teams should identify such authentication mechanisms and work on them so that this can get fixed. The design teams must look at the protocols that they are working on and see if packets captured from the previous/stale sessions can be replayed.


What might also influence the design is the rate at which the protocol packets are originated. In case of protocols like BFD, where packets are originated at millisecond intervals, there are some special considerations that must be kept in mind when defining the new authentication and security mechanisms.


The designers should also consider whether the current authentication mechanisms impose considerable processing overhead on a router that's doing authentication. Most currently deployed routers do not have hardware accelerators for cryptographic processing and these operations can impose a significant processing burden under some circumstances. The proposed solutions should be evaluated carefully with regard to the processing burden that they will impose, since deployment may be impeded if network operators perceive that a solution will impose a processing burden which either entails substantial capital expenses or threatens to destabilize the routers.


9. Security Considerations
9. 安全考虑

As mentioned in the Introduction, RFC 4948 [RFC4948] identifies additional steps needed to achieve the overall goal of improving the security of the core routing infrastructure. Those include validation of route origin announcements, path validation, cleaning up the IRR databases for accuracy, and operational security practices that prevent routers from becoming compromised devices. The KARP work is but one step needed to improve core routing infrastructure.

如引言中所述,RFC 4948[RFC4948]确定了实现提高核心路由基础设施安全性的总体目标所需的其他步骤。这些包括验证路由来源公告、路径验证、清理IRR数据库以确保准确性,以及防止路由器成为受损设备的操作安全实践。KARP工作只是改进核心路由基础设施所需的一步。

The security of cryptographic-based systems depends on both the strength of the cryptographic algorithms chosen and the strength of the keys used with those algorithms. The security also depends on the engineering of the protocol used by the system to ensure that there are no non-cryptographic ways to bypass the security of the overall system.


9.1. Use Strong Keys
9.1. 使用强键

Care should be taken to ensure that the selected key is unpredictable, avoiding any keys known to be weak for the algorithm in use. [RFC4086] contains helpful information on both key generation techniques and cryptographic randomness.


Care should also be taken when choosing the length of the key. [RFC3766] provides some additional information on asymmetric and symmetric key sizes and how they relate to system requirements for attack resistance.


In addition to using a key of appropriate length and randomness, deployers of KARP should use different keys between different routing peers whenever operationally possible. This is especially true when the routing protocol takes a static traffic key as opposed to a traffic key derived on a per-connection basis using a KDF. The burden for doing so is understandably much higher than using the same static traffic key across all peering routers. Depending upon the specific KMP, it can be argued that generally using a KMP network-wide increases peer-wise security. Consider an attacker that learns or guesses the traffic key used by two peer routers: if the traffic key is only used between those two routers, then the attacker has only compromised that one connection not the entire network.


However whenever using manual keys, it is best to design a system where a given pre-shared key (PSK) will be used in a KDF mixed with connection-specific material, in order to generate session unique -- and therefore peer-wise -- traffic keys. Doing so has the following advantages: the traffic keys used in the per-message authentication mechanism are peer-wise unique, it provides inter-connection replay protection, and if the per-message authentication mechanism covers some connection counter, intra-connection replay protection.


Note that certain key derivation functions (e.g., KDF_AES_128_CMAC) as used in TCP-AO [RFC5926], the pseudorandom function (PRF) used in the KDF may require a key of a certain fixed size as an input.


For example, AES_128_CMAC requires a 128-bit (16-byte) key as the seed. However, for the convenience of the administrators, a specification may not want to require the entry of a PSK be of exactly 16 bytes. Instead, a specification may call for a key prep routine that could handle a variable-length PSK, one that might be less or more than 16 bytes (see [RFC4615], Section 3, as an example). That key prep routine would derive a key of exactly the required length, thus, be suitable as a seed to the PRF. This does NOT mean that administrators are safe to use weak keys. Administrators are encouraged to follow [RFC4086] [NIST-800-118]. We simply attempted


to "put a fence around stupidity", as much as possible as it's hard to imagine administrators putting in a password that is, say 16 bytes in length.


A better option, from a security perspective, is to use some representation of a device-specific asymmetric key pair as the identity proof, as described in section "Unique versus Shared Keys" section.


9.2. Internal versus External Operation
9.2. 内部操作与外部操作

Design teams must consider whether the protocol is an internal routing protocol or an external one, i.e., does it primarily run between peers within a single domain of control or between two different domains of control? Some protocols may be used in both cases, internally and externally, and as such, various modes of authentication operation may be required for the same protocol. While it is preferred that all routing exchanges run with the best security mechanisms enabled in all deployment contexts, this exhortation is greater for those protocols running on inter-domain point-to-point links. It is greatest for those on shared access link layers with several different domains interchanging together, because the volume of attackers are greater from the outside. Note however, that the consequences of internal attacks maybe no less severe -- in fact, they may be quite a bit more severe -- than an external attack. An example of this internal versus external consideration is BGP, which has both EBGP and IBGP modes. Another example is a multicast protocol where the neighbors are sometimes within a domain of control and sometimes at an inter-domain exchange point. In the case of PIM-SM running on an internal multi-access link, it would be acceptable to give up some security to get some convenience by using a group key among the peers on the link. On the other hand, in the case of PIM-SM running over a multi-access link at a public exchange point, operators may favor security over convenience by using unique pair-wise keys for every peer. Designers must consider both modes of operation and ensure the authentication mechanisms fit both.


Operators are encouraged to run cryptographic authentication on all their adjacencies, but to work from the outside in, i.e., External BGP (EBGP) links are a higher priority than the Internal BGP (IBGP) links because they are externally facing, and, as a result, more likely to be targeted in an attack.


9.3. Unique versus Shared Keys
9.3. 唯一密钥与共享密钥

This section discusses security considerations regarding when it is appropriate to use the same authentication key inputs for multiple peers and when it is not. This is largely a debate of convenience


versus security. It is often the case that the best secured mechanism is also the least convenient mechanism. For example, an air gap between a host and the network absolutely prevents remote attacks on the host, but having to copy and carry files using the "sneaker net" is quite inconvenient and does not scale.


Operators have erred on the side of convenience when it comes to securing routing protocols with cryptographic authentication. Many do not use it at all. Some use it only on external links, but not on internal links. Those that do use it often use the same key for all peers in a network. It is common to see the same key in use for years, e.g., the key was entered when authentication mechanisms were originally configured or when the routing gear was deployed.


One goal for designers is to create authentication and integrity mechanisms that are easy for operators to deploy and manage, and still use unique keys between peers (or small groups on multi-access links) and for different sessions among the same peers. Operators have the impression that they NEED one key shared across the network, when, in fact, they do not. What they need is the relative convenience they experience from deploying cryptographic authentication with one key (or a few keys) compared to the inconvenience they would experience if they deployed the same authentication mechanism using unique pair-wise keys. An example is BGP route reflectors. Here, operators often use the same authentication key between each client and the route reflector. The roadmaps defined from this guidance document should allow for unique keys to be used between each client and the peer, without sacrificing much convenience. Designers should strive to deliver peer-wise unique keying mechanisms with similar ease-of-deployment properties as today's one-key method.


Operators must understand the consequences of using the same key across many peers. One argument against using the same key is that if the same key that is used in multiple devices, then a compromise of any one of the devices will expose the key. Also, since the same key is supported on many devices, this is known by many people, which affects its distribution to all of the devices.


Consider also the attack consequence size, the amount of routing adjacencies that can be negatively affected once a breach has occurred, i.e., once the keys have been acquired by the attacker.


Again, if a shared key is used across the internal domain, then the consequence size is the whole network. Ideally, unique key pairs would be used for each adjacency.


In some cases, use of shared keys is needed because of the problem space. For example, a multicast packet is sent once but then consumed by several routing neighbors. If unique keys were used per neighbor, the benefit of multicast would be erased because the sender would have to create a different announcement packet for each receiver. Though this may be desired and acceptable in some small number of use cases, it is not the norm. Shared (i.e., group) keys are an acceptable solution here, and much work has been done already in this area (by the MSEC working group).


9.4. Key Exchange Mechanism
9.4. 密钥交换机制

This section discusses the security and use case considerations for key exchange for routing protocols. Two options exist: an out-of-band mechanism or a KMP. An out-of-band mechanism involves operators configuring keys in the device through a configuration tool or management method (e.g., Simple Network Management Protocol (SNMP), Network Configuration Protocol (NETCONF)). A KMP is an automated protocol that exchanges keys without operator intervention. KMPs can occur either in-band to the routing protocol or out-of-band to the routing protocol (i.e., a different protocol).


An example of an out-of-band configuration mechanism could be an administrator who makes a remote management connection (e.g., using SSH) to a router and manually enters the keying information, e.g., the algorithm, the key(s), the key lifetimes, etc. Another example could be an OSS system that inputs the same information by using a script over an SSH connection or by pushing configuration through some other management connection, standard (NETCONF-based) or proprietary.


The drawbacks of an out-of-band configuration mechanism include lack of scalability, complexity, and speed of changing if a security breach is suspected. For example, if an employee who had access to keys was terminated, or if a machine holding those keys was believed to be compromised, then the system would be considered insecure and vulnerable until new keys were generated and distributed. Those keys then need to be placed into the OSS system, and the OSS system then needs to push the new keys -- often during a very limited change window -- into the relevant devices. If there are multiple organizations involved in these connections, because the protected connections are inter-domain, this process is very complicated.


The principle benefit of out-of-band configuration mechanism is that once the new keys/parameters are set in OSS system, they can be pushed automatically to all devices within the OSS's domain.


Operators have mechanisms in place for this already for managing other router configuration data. In small environments with few routers, a manual system is not difficult to employ.


We further define a peer-to-peer KMP as using cryptographically protected identity verification, session key negotiation, and security association parameter negotiation between the two routing peers. The KMP among peers may also include the negotiation of parameters, like cryptographic algorithms, cryptographic inputs (e.g., initialization vectors), key lifetimes, etc.


There are several benefits of a peer-to-peer KMP versus centrally managed and distributing keys. It results in key(s) that are privately generated, and it need not be recorded permanently anywhere. Since the traffic keys used in a particular connection are not a fixed part of a device configuration, no security sensitive data exists anywhere else in the operator's systems that can be stolen, e.g., in the case of a terminated or turned employee. If a server or other data store is stolen or compromised, the thieves gain limited or no access to current traffic keys. They may gain access to key derivation material, like a PSK, but may not be able to access the current traffic keys in use. In this example, these PSKs can be updated in the device configurations (either manually or through an OSS) without bouncing or impacting the existing session at all. In the case of using raw asymmetric keys or certificates, instead of PSKs, the data theft (from the data store) would likely not result in any compromise, as the key pairs would have been generated on the routers and never leave those routers. In such a case, no changes are needed on the routers; the connections will continue to be secure, uncompromised. Additionally, with a KMP, regular rekey operations occur without any operator involvement or oversight. This keeps keys fresh.


There are a few drawbacks to using a KMP. First, a KMP requires more cryptographic processing for the router at the beginning of a connection. This will add some minor start-up time to connection establishment versus a purely manual key management approach. Once a connection with traffic keys has been established via a KMP, the performance is the same in the KMP and the out-of-band configuration case. KMPs also add another layer of protocol and configuration complexity, which can fail or be misconfigured. This was more of an issue when these KMPs were first deployed, but less so as these implementations and operational experience with them have matured.


One of the goals for KARP is to develop a KMP; an out-of-band configuration protocol for key exchange is out of scope.


Within this constraint, there are two approaches for a KMP:


The first is to use a KMP that runs independent of the routing and the signaling protocols. It would run on its own port and use its own transport (to avoid interfering with the routing protocol that it is serving). When a routing protocol needs a key, it would contact the local instance of this key management protocol and request a key. The KMP generates a key that is delivered to the routing protocol for it to use for authenticating and integrity verification of the routing protocol packets. This KMP could either be an existing key management protocol such as ISAKMP/IKE, GKMP, etc., extended for the routing protocols, or it could be a new KMP, designed for the routing protocol context.


The second approach is to define an in-band KMP extension for existing routing protocols putting the key management mechanisms inside the protocol itself. In this case, the key management messages would be carried within the routing protocol packets, resulting in very tight coupling between the routing protocols and the key management protocol.


10. Acknowledgments
10. 致谢

Much of the text for this document came originally from "Roadmap for Cryptographic Authentication of Routing Protocol Packets on the Wire", authored by Gregory M. Lebovitz.

本文档的大部分文本最初来自Gregory M.Lebovitz编写的“在线路由协议包加密认证路线图”。

We would like to thank Sam Hartman, Eric Rescorla, Russ White, Sean Turner, Stephen Kent, Stephen Farrell, Adrian Farrel, Russ Housley, Michael Barnes, and Vishwas Manral for their comments on the document.


11. References
11. 工具书类
11.1. Normative References
11.1. 规范性引用文件

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC2119]Bradner,S.,“RFC中用于表示需求水平的关键词”,BCP 14,RFC 2119,1997年3月。

[RFC4948] Andersson, L., Davies, E., and L. Zhang, "Report from the IAB workshop on Unwanted Traffic March 9-10, 2006", RFC 4948, August 2007.

[RFC4948]Andersson,L.,Davies,E.,和L.Zhang,“IAB 2006年3月9日至10日不必要交通研讨会报告”,RFC 4948,2007年8月。

11.2. Informative References
11.2. 资料性引用

[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, December 1990.

[RFC1195]Callon,R.,“OSI IS-IS在TCP/IP和双环境中的路由使用”,RFC 11951990年12月。

[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997.

[RFC2205]Braden,R.,Ed.,Zhang,L.,Berson,S.,Herzog,S.,和S.Jamin,“资源预留协议(RSVP)——版本1功能规范”,RFC 22052997年9月。

[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

[RFC2328]Moy,J.,“OSPF版本2”,STD 54,RFC 2328,1998年4月。

[RFC2453] Malkin, G., "RIP Version 2", STD 56, RFC 2453, November 1998.

[RFC2453]Malkin,G.,“RIP版本2”,STD 56,RFC 2453,1998年11月。

[RFC2747] Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic Authentication", RFC 2747, January 2000.

[RFC2747]Baker,F.,Lindell,B.和M.Talwar,“RSVP加密认证”,RFC 2747,2000年1月。

[RFC3097] Braden, R. and L. Zhang, "RSVP Cryptographic Authentication -- Updated Message Type Value", RFC 3097, April 2001.

[RFC3097]Braden,R.和L.Zhang,“RSVP加密身份验证——更新的消息类型值”,RFC 3097,2001年4月。

[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001.

[RFC3209]Awduche,D.,Berger,L.,Gan,D.,Li,T.,Srinivasan,V.,和G.Swallow,“RSVP-TE:LSP隧道RSVP的扩展”,RFC 3209,2001年12月。

[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

[RFC3473]Berger,L.,Ed.“通用多协议标签交换(GMPLS)信令资源预留协议流量工程(RSVP-TE)扩展”,RFC 3473,2003年1月。

[RFC3618] Fenner, B., Ed., and D. Meyer, Ed., "Multicast Source Discovery Protocol (MSDP)", RFC 3618, October 2003.

[RFC3618]Fenner,B.,Ed.,和D.Meyer,Ed.,“多播源发现协议(MSDP)”,RFC 3618,2003年10月。

[RFC3766] Orman, H. and P. Hoffman, "Determining Strengths For Public Keys Used For Exchanging Symmetric Keys", BCP 86, RFC 3766, April 2004.

[RFC3766]Orman,H.和P.Hoffman,“确定用于交换对称密钥的公钥的强度”,BCP 86,RFC 3766,2004年4月。

[RFC3973] Adams, A., Nicholas, J., and W. Siadak, "Protocol Independent Multicast - Dense Mode (PIM-DM): Protocol Specification (Revised)", RFC 3973, January 2005.

[RFC3973]Adams,A.,Nicholas,J.,和W.Siadak,“协议独立多播-密集模式(PIM-DM):协议规范(修订版)”,RFC 3973,2005年1月。

[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", BCP 106, RFC 4086, June 2005.

[RFC4086]Eastlake 3rd,D.,Schiller,J.,和S.Crocker,“安全的随机性要求”,BCP 106,RFC 4086,2005年6月。

[RFC4107] Bellovin, S. and R. Housley, "Guidelines for Cryptographic Key Management", BCP 107, RFC 4107, June 2005.

[RFC4107]Bellovin,S.和R.Housley,“加密密钥管理指南”,BCP 107,RFC 4107,2005年6月。

[RFC4230] Tschofenig, H. and R. Graveman, "RSVP Security Properties", RFC 4230, December 2005.

[RFC4230]Tschofenig,H.和R.Graveman,“RSVP安全属性”,RFC 4230,2005年12月。

[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Authentication Protocol", RFC 4252, January 2006.

[RFC4252]Ylonen,T.和C.Lonvick,Ed.,“安全外壳(SSH)认证协议”,RFC 4252,2006年1月。

[RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Transport Layer Protocol", RFC 4253, January 2006.

[RFC4253]Ylonen,T.和C.Lonvick,编辑,“安全外壳(SSH)传输层协议”,RFC 4253,2006年1月。

[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006.

[RFC4271]Rekhter,Y.,Ed.,Li,T.,Ed.,和S.Hares,Ed.,“边境网关协议4(BGP-4)”,RFC 42712006年1月。

[RFC4492] Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B. Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS)", RFC 4492, May 2006.

[RFC4492]Blake Wilson,S.,Bolyard,N.,Gupta,V.,Hawk,C.,和B.Moeller,“用于传输层安全(TLS)的椭圆曲线密码(ECC)密码套件”,RFC 4492,2006年5月。

[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", RFC 4601, August 2006.

[RFC4601]Fenner,B.,Handley,M.,Holbrook,H.,和I.Kouvelas,“协议独立多播-稀疏模式(PIM-SM):协议规范(修订版)”,RFC 46012006年8月。

[RFC4615] Song, J., Poovendran, R., Lee, J., and T. Iwata, "The Advanced Encryption Standard-Cipher-based Message Authentication Code-Pseudo-Random Function-128 (- AES-CMAC-PRF-128) Algorithm for the Internet Key Exchange Protocol (IKE)", RFC 4615, August 2006.

[RFC4615]Song,J.,Poovendran,R.,Lee,J.,和T.Iwata,“互联网密钥交换协议(IKE)的基于密码的消息认证码伪随机函数128(-AES-CMAC-PRF-128)算法的高级加密标准”,RFC 4615,2006年8月。

[RFC4726] Farrel, A., Vasseur, J.-P., and A. Ayyangar, "A Framework for Inter-Domain Multiprotocol Label Switching Traffic Engineering", RFC 4726, November 2006.

[RFC4726]Farrel,A.,Vasseur,J.-P.,和A.Ayyangar,“域间多协议标签交换流量工程框架”,RFC 4726,2006年11月。

[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed., "LDP Specification", RFC 5036, October 2007.

[RFC5036]Andersson,L.,Ed.,Minei,I.,Ed.,和B.Thomas,Ed.,“LDP规范”,RFC 5036,2007年10月。

[RFC5082] Gill, V., Heasley, J., Meyer, D., Savola, P., Ed., and C. Pignataro, "The Generalized TTL Security Mechanism (GTSM)", RFC 5082, October 2007.

[RFC5082]Gill,V.,Heasley,J.,Meyer,D.,Savola,P.,Ed.,和C.Pignataro,“广义TTL安全机制(GTSM)”,RFC 5082,2007年10月。

[RFC5151] Farrel, A., Ed., Ayyangar, A., and JP. Vasseur, "Inter-Domain MPLS and GMPLS Traffic Engineering -- Resource Reservation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 5151, February 2008.

[RFC5151]Farrel,A.,Ed.,Ayyangar,A.,和JP。Vasseur,“域间MPLS和GMPLS流量工程——资源预留协议流量工程(RSVP-TE)扩展”,RFC 51512008年2月。

[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, May 2008.

[RFC5280]Cooper,D.,Santesson,S.,Farrell,S.,Boeyen,S.,Housley,R.,和W.Polk,“Internet X.509公钥基础设施证书和证书撤销列表(CRL)配置文件”,RFC 52802008年5月。

[RFC5440] Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009.

[RFC5440]Vasseur,JP.,Ed.,和JL。Le Roux,Ed.“路径计算元素(PCE)通信协议(PCEP)”,RFC 54402009年3月。

[RFC5796] Atwood, W., Islam, S., and M. Siami, "Authentication and Confidentiality in Protocol Independent Multicast Sparse Mode (PIM-SM) Link-Local Messages", RFC 5796, March 2010.

[RFC5796]Atwood,W.,Islam,S.,和M.Siami,“协议独立多播稀疏模式(PIM-SM)链路本地消息中的身份验证和机密性”,RFC 57962010年3月。

[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, June 2010.

[RFC5880]Katz,D.和D.Ward,“双向转发检测(BFD)”,RFC 58802010年6月。

[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP Authentication Option", RFC 5925, June 2010.

[RFC5925]Touch,J.,Mankin,A.,和R.Bonica,“TCP认证选项”,RFC 59252010年6月。

[RFC5926] Lebovitz, G. and E. Rescorla, "Cryptographic Algorithms for the TCP Authentication Option (TCP-AO)", RFC 5926, June 2010.

[RFC5926]Lebovitz,G.和E.Rescorla,“TCP认证选项(TCP-AO)的加密算法”,RFC 5926,2010年6月。

[RFC6039] Manral, V., Bhatia, M., Jaeggli, J., and R. White, "Issues with Existing Cryptographic Protection Methods for Routing Protocols", RFC 6039, October 2010.

[RFC6039]Manral,V.,Bhatia,M.,Jaeggli,J.,和R.White,“路由协议现有加密保护方法的问题”,RFC 6039,2010年10月。

[RFC6407] Weis, B., Rowles, S., and T. Hardjono, "The Group Domain of Interpretation", RFC 6407, October 2011.

[RFC6407]Weis,B.,Rowles,S.,和T.Hardjono,“解释的集团领域”,RFC 6407,2011年10月。

[THTS-REQS] Lebovitz, G., "The Threat Analysis and Requirements for Cryptographic Authentication of Routing Protocols' Transports", Work in Progress, June 2011.


[CRPT-TAB] Housley, R. and Polk, T., "Database of Long-Lived Symmetric Cryptographic Keys", Work in Progress, October 2011


[GDOI-MAC] Weis, B. and S. Rowles, "GDOI Generic Message Authentication Code Policy", Work in Progress, September 2011.


[IRR] Merit Network Inc , "Internet Routing Registry Routing Assets Database", 2006,


[NIST-800-57] US National Institute of Standards & Technology, "Recommendation for Key Management Part 1: General (Revised)", March 2007


[NIST-800-118] US National Institute of Standards & Technology, "Guide to Enterprise Password Management (Draft)", April 2009


Authors' Addresses


Gregory M. Lebovitz Aptos, California USA 95003

Gregory M.Lebovitz Aptos,美国加利福尼亚州95003


Manav Bhatia Alcatel-Lucent Bangalore India