Network Working Group A. Lindem, Ed. Internet-Draft Cisco Systems Intended status: Standards Track Y. Qu Expires: October 28, 2017 Huawei D. Yeung Arrcus, Inc I. Chen Jabil J. Zhang Juniper Networks April 26, 2017 Routing Key Chain YANG Data Model draft-ietf-rtgwg-yang-key-chain-21.txt Abstract This document describes the key chain YANG data model. Key chains are commonly used for routing protocol authentication and other applications requiring symmetric keys. A key chain is a list of elements each containing a key string, send lifetime, accept lifetime, and algorithm (authentication or encryption). By properly overlapping the send and accept lifetimes of multiple key chain elements, key strings and algorithms may be gracefully updated. By representing them in a YANG data model, key distribution can be automated. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on October 28, 2017. Lindem, et al. Expires October 28, 2017 [Page 1] Internet-Draft YANG Key Chain April 2017 Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Notation . . . . . . . . . . . . . . . . . . 3 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 3 2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Graceful Key Rollover using Key Chains . . . . . . . . . 4 3. Design of the Key Chain Model . . . . . . . . . . . . . . . . 5 3.1. Key Chain Operational State . . . . . . . . . . . . . . . 6 3.2. Key Chain Model Features . . . . . . . . . . . . . . . . 6 3.3. Key Chain Model Tree . . . . . . . . . . . . . . . . . . 6 4. Key Chain YANG Model . . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 15 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 16 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 8.1. Normative References . . . . . . . . . . . . . . . . . . 16 8.2. Informative References . . . . . . . . . . . . . . . . . 17 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 18 A.1. Simple Key Chain with Always Valid Single Key . . . . . . 19 A.2. Key Chain with Keys having Different Lifetimes . . . . . 19 A.3. Key Chain with Independent Send and Accept Lifetimes . . 21 Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 1. Introduction This document describes the key chain YANG [YANG] data model. Key chains are commonly used for routing protocol authentication and other applications requiring symmetric keys. A key chain is a list of elements each containing a key string, send lifetime, accept lifetime, and algorithm (authentication or encryption). By properly Lindem, et al. Expires October 28, 2017 [Page 2] Internet-Draft YANG Key Chain April 2017 overlapping the send and accept lifetimes of multiple key chain elements, key strings and algorithms may be gracefully updated. By representing them in a YANG data model, key distribution can be automated. In some applications, the protocols do not use the key chain element key directly, but rather a key derivation function is used to derive a short-lived key from the key chain element key (e.g., the Master Keys used in [TCP-AO]). 1.1. Requirements Notation The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC-KEYWORDS]. 1.2. Tree Diagrams A simplified graphical representation of the complete data tree is presented in Section 3.3. The following tree notation is used. o Brackets "[" and "]" enclose YANG list keys. These YANG list keys should not be confused with the key-chain keys. o Curly braces "{" and "}" contain names of optional features that make the corresponding node conditional. o Abbreviations before data node names: "rw" means configuration (read-write), "ro" state data (read-only), "-x" RPC operations, and "-n" notifications. o Symbols after data node names: "?" means an optional node, "!" a container with presence, and "*" denotes a "list" or "leaf-list". o Parentheses enclose choice and case nodes, and case nodes are also marked with a colon (":"). o Ellipsis ("...") stands for contents of subtrees that are not shown. 2. Problem Statement This document describes a YANG [YANG] data model for key chains. Key chains have been implemented and deployed by a large percentage of network equipment vendors. Providing a standard YANG model will facilitate automated key distribution and non-disruptive key Lindem, et al. Expires October 28, 2017 [Page 3] Internet-Draft YANG Key Chain April 2017 rollover. This will aid in tightening the security of the core routing infrastructure as recommended in [IAB-REPORT]. A key chain is a list containing one or more elements containing a Key ID, key string, send/accept lifetimes, and the associated authentication or encryption algorithm. A key chain can be used by any service or application requiring authentication or encryption using symmetric keys. In essence, the key-chain is a reusable key policy that can be referenced wherever it is required. The key-chain construct has been implemented by most networking vendors and deployed in many networks. A conceptual representation of a crypto key table is described in [CRYPTO-KEYTABLE]. The crypto key table also includes keys as well as their corresponding lifetimes and algorithms. Additionally, the key table includes key selection criteria and envisions a deployment model where the details of the applications or services requiring authentication or encryption permeate into the key database. The YANG key-chain model described herein doesn't include key selection criteria or support this deployment model. At the same time, it does not preclude it. The draft [YANG-CRYPTO-KEYTABLE] describes augmentations to the key chain YANG model in support of key selection criteria. 2.1. Applicability Other YANG modules may reference ietf-key-chain YANG module key-chain names for authentication and encryption applications. A YANG type has been provided to facilitate reference to the key-chain name without having to specify the complete YANG XML Path Language (XPath) selector. 2.2. Graceful Key Rollover using Key Chains Key chains may be used to gracefully update the key string and/or algorithm used by an application for authentication or encryption. To achieve graceful key rollover, the receiver MAY accept all the keys that have a valid accept lifetime and the sender MAY send the key with the most recent send lifetime. One scenario for facilitating key rollover is to: 1. Distribute a key chain with a new key to all the routers or other network devices in the domain of that key chain. The new key's accept lifetime should be such that it is accepted during the key rollover period. The send lifetime should be a time in the future when it can be assured that all the routers in the domain of that key are upgraded. This will have no immediate impact on the keys used for transmission. Lindem, et al. Expires October 28, 2017 [Page 4] Internet-Draft YANG Key Chain April 2017 2. Assure that all the network devices have been updated with the updated key chain and that their system times are roughly synchronized. The system times of devices within an administrative domain are commonly synchronized (e.g., using Network Time Protocol (NTP) [NTP-PROTO]). This also may be automated. 3. When the send lifetime of the new key becomes valid, the network devices within the domain of key chain will using the new key for transmissions. 4. At some point in the future, a new key chain with the old key removed may be distributed to the network devices within the domain of the key chain. However, this may be deferred until the next key rollover. If this is done, the key chain will always include two keys; either the current and future key (during key rollovers) or the current and previous keys (between key rollovers). Since the most recent send lifetime is defined as the one with the latest start-time, specification of "always" will prevent using the graceful key rollover technique described above. Other key configuration and usage scenarios are possible but these are beyond the scope of this document. 3. Design of the Key Chain Model The ietf-key-chain module contains a list of one or more keys indexed by a Key ID. For some applications (e.g., OSPFv3 [OSPFV3-AUTH]), the Key ID is used to identify the key chain key to be used. In addition to the Key ID, each key chain key includes a key-string and a cryptographic algorithm. Optionally, the key chain keys include send/accept lifetimes. If the send/accept lifetime is unspecified, the key is always considered valid. Note that different key values for transmission versus acceptance may be supported with multiple key chain elements. The key used for transmission will have a valid send-lifetime and invalid accept- lifetime (e.g., has an end-time equal to the start-time). The key used for acceptance will have a valid accept-lifetime and invalid send-lifetime. Due to the differences in key chain implementations across various vendors, some of the data elements are optional. Finally, the crypto algorithm identities are provided for reuse when configuring legacy authentication and encryption not using key-chains. Lindem, et al. Expires October 28, 2017 [Page 5] Internet-Draft YANG Key Chain April 2017 A key-chain is identified by a unique name within the scope of the network device. The "key-chain-ref" typedef SHOULD be used by other YANG modules when they need to reference a configured key-chain. 3.1. Key Chain Operational State The key chain operational state is included in the same tree as key chain configuration consistent with Network Management Datastore Architecture [NMDA]. The timestamp of the last key chain modification is also maintained in the operational state. Additionally, the operational state includes an indication of whether or not a key chain key is valid for sending or acceptance. 3.2. Key Chain Model Features Features are used to handle differences between vendor implementations. For example, not all vendors support configuration of an acceptance tolerance or configuration of key strings in hexadecimal. They are also used to support of security requirements (e.g., TCP-AO Algorithms [TCP-AO-ALGORITHMS]) not yet implemented by vendors or only a single vendor. 3.3. Key Chain Model Tree +--rw key-chains +--rw key-chain* [name] +--rw name string +--rw description? string +--rw accept-tolerance {accept-tolerance}? | +--rw duration? uint32 +--ro last-modified-timestamp? yang:date-and-time +--rw key* [key-id] +--rw key-id uint64 +--rw lifetime | +--rw (lifetime)? | +--:(send-and-accept-lifetime) | | +--rw send-accept-lifetime | | +--rw (lifetime)? | | +--:(always) | | | +--rw always? empty | | +--:(start-end-time) | | +--rw start-date-time? | | | yang:date-and-time | | +--rw (end-time)? | | +--:(infinite) | | | +--rw no-end-time? empty | | +--:(duration) | | | +--rw duration? uint32 Lindem, et al. Expires October 28, 2017 [Page 6] Internet-Draft YANG Key Chain April 2017 | | +--:(end-date-time) | | +--rw end-date-time? | | yang:date-and-time | +--:(independent-send-accept-lifetime) | | {independent-send-accept-lifetime}? | +--rw send-lifetime | | +--rw (lifetime)? | | +--:(always) | | | +--rw always? empty | | +--:(start-end-time) | | +--rw start-date-time? | | yang:date-and-time | | +--rw (end-time)? | | +--:(infinite) | | | +--rw no-end-time? empty | | +--:(duration) | | | +--rw duration? uint32 | | +--:(end-date-time) | | +--rw end-date-time? | | yang:date-and-time | +--rw accept-lifetime | +--rw (lifetime)? | +--:(always) | | +--rw always? empty | +--:(start-end-time) | +--rw start-date-time? | | yang:date-and-time | +--rw (end-time)? | +--:(infinite) | | +--rw no-end-time? empty | +--:(duration) | | +--rw duration? uint32 | +--:(end-date-time) | +--rw end-date-time? | yang:date-and-time +--rw crypto-algorithm identityref +--rw key-string | +--rw (key-string-style)? | +--:(keystring) | | +--rw keystring? string | +--:(hexadecimal) {hex-key-string}? | +--rw hexadecimal-string? yang:hex-string +--ro send-lifetime-active? boolean +--ro accept-lifetime-active? boolean Lindem, et al. Expires October 28, 2017 [Page 7] Internet-Draft YANG Key Chain April 2017 4. Key Chain YANG Model file "ietf-key-chain@2017-04-18.yang" module ietf-key-chain { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-key-chain"; prefix key-chain; import ietf-yang-types { prefix yang; } import ietf-netconf-acm { prefix nacm; } organization "IETF RTG (Routing) Working Group"; contact "Acee Lindem - acee@cisco.com"; description "This YANG module defines the generic configuration data for key-chain. It is intended that the module will be extended by vendors to define vendor-specific key-chain configuration parameters. Copyright (c) 2017 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2017-04-18 { description "Initial RFC Revision"; reference "RFC XXXX: A YANG Data Model for key-chain"; } feature hex-key-string { description "Support hexadecimal key string."; } Lindem, et al. Expires October 28, 2017 [Page 8] Internet-Draft YANG Key Chain April 2017 feature accept-tolerance { description "Support the tolerance or acceptance limit."; } feature independent-send-accept-lifetime { description "Support for independent send and accept key lifetimes."; } feature crypto-hmac-sha-1-12 { description "Support for TCP HMAC-SHA-1 12 byte digest hack."; } feature clear-text { description "Support for clear-text algorithm. Usage is NOT RECOMMENDED."; } feature aes-cmac-prf-128 { description "Support for AES Cipher based Message Authentication Code Pseudo Random Function."; } feature replay-protection-only { description "Provide replay-protection without any authentication as required by protocols such as Bidirectional Forwarding Detection (BFD)."; } identity crypto-algorithm { description "Base identity of cryptographic algorithm options."; } identity hmac-sha-1-12 { base crypto-algorithm; if-feature "crypto-hmac-sha-1-12"; description "The HMAC-SHA1-12 algorithm."; } identity aes-cmac-prf-128 { base crypto-algorithm; if-feature "aes-cmac-prf-128"; Lindem, et al. Expires October 28, 2017 [Page 9] Internet-Draft YANG Key Chain April 2017 description "The AES-CMAC-PRF-128 algorithm - required by RFC 5926 for TCP-AO key derivation functions."; } identity md5 { base crypto-algorithm; description "The MD5 algorithm."; } identity sha-1 { base crypto-algorithm; description "The SHA-1 algorithm."; } identity hmac-sha-1 { base crypto-algorithm; description "HMAC-SHA-1 authentication algorithm."; } identity hmac-sha-256 { base crypto-algorithm; description "HMAC-SHA-256 authentication algorithm."; } identity hmac-sha-384 { base crypto-algorithm; description "HMAC-SHA-384 authentication algorithm."; } identity hmac-sha-512 { base crypto-algorithm; description "HMAC-SHA-512 authentication algorithm."; } identity clear-text { base crypto-algorithm; if-feature "clear-text"; description "Clear text."; } Lindem, et al. Expires October 28, 2017 [Page 10] Internet-Draft YANG Key Chain April 2017 identity replay-protection-only { base crypto-algorithm; if-feature "replay-protection-only"; description "Provide replay-protection without any authentication as required by protocols such as Bidirectional Forwarding Detection (BFD)."; } typedef key-chain-ref { type leafref { path "/key-chain:key-chains/key-chain:key-chain/key-chain:name"; } description "This type is used by data models that need to reference configured key-chains."; } grouping lifetime { description "Key lifetime specification."; choice lifetime { default "always"; description "Options for specifying key accept or send lifetimes"; case always { leaf always { type empty; description "Indicates key lifetime is always valid."; } } case start-end-time { leaf start-date-time { type yang:date-and-time; description "Start time."; } choice end-time { default "infinite"; description "End-time setting."; case infinite { leaf no-end-time { type empty; description "Indicates key lifetime end-time is infinite."; Lindem, et al. Expires October 28, 2017 [Page 11] Internet-Draft YANG Key Chain April 2017 } } case duration { leaf duration { type uint32 { range "1..2147483646"; } units "seconds"; description "Key lifetime duration, in seconds"; } } case end-date-time { leaf end-date-time { type yang:date-and-time; description "End time."; } } } } } } grouping key-common { description "Key-chain key data nodes common to configuration and state."; } container key-chains { description "All configured key-chains on the device."; list key-chain { key "name"; description "List of key-chains."; leaf name { type string; description "Name of the key-chain."; } leaf description { type string; description "A description of the key-chain"; } container accept-tolerance { if-feature "accept-tolerance"; Lindem, et al. Expires October 28, 2017 [Page 12] Internet-Draft YANG Key Chain April 2017 description "Tolerance for key lifetime acceptance (seconds)."; leaf duration { type uint32; units "seconds"; default "0"; description "Tolerance range, in seconds."; } } leaf last-modified-timestamp { type yang:date-and-time; config false; description "Timestamp of the most recent update to the key-chain"; } list key { key "key-id"; description "Single key in key chain."; leaf key-id { type uint64; description "Numeric value uniquely identifying the key"; } container lifetime { description "Specify a key's lifetime."; choice lifetime { description "Options for specification of send and accept lifetimes."; case send-and-accept-lifetime { description "Send and accept key have the same lifetime."; container send-accept-lifetime { description "Single lifetime specification for both send and accept lifetimes."; uses lifetime; } } case independent-send-accept-lifetime { if-feature "independent-send-accept-lifetime"; description "Independent send and accept key lifetimes."; container send-lifetime { description Lindem, et al. Expires October 28, 2017 [Page 13] Internet-Draft YANG Key Chain April 2017 "Separate lifetime specification for send lifetime."; uses lifetime; } container accept-lifetime { description "Separate lifetime specification for accept lifetime."; uses lifetime; } } } } leaf crypto-algorithm { type identityref { base crypto-algorithm; } mandatory true; description "Cryptographic algorithm associated with key."; } container key-string { description "The key string."; nacm:default-deny-all; choice key-string-style { description "Key string styles"; case keystring { leaf keystring { type string; description "Key string in ASCII format."; } } case hexadecimal { if-feature "hex-key-string"; leaf hexadecimal-string { type yang:hex-string; description "Key in hexadecimal string format. When compared to ASCII, specification in hexadecimal affords greater key entropy with the same number of internal key-string octets. Additionally, it discourages usage of well-known words or numbers."; } } Lindem, et al. Expires October 28, 2017 [Page 14] Internet-Draft YANG Key Chain April 2017 } } leaf send-lifetime-active { type boolean; config false; description "Indicates if the send lifetime of the key-chain key is currently active."; } leaf accept-lifetime-active { type boolean; config false; description "Indicates if the accept lifetime of the key-chain key is currently active."; } } } } } 5. Security Considerations The YANG module defined in this document is designed to be accessed via network management protocols such as NETCONF [NETCONF] or RESTCONF [RESTCONF]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [NETCONF-SSH]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [TLS]. The NETCONF access control model [NETCONF-ACM] provides the means to restrict access for particular NETCONF or RESTCONF users to a pre- configured subset of all available NETCONF or RESTCONF protocol operations and content. The key strings are not accessible by default and NETCONF Access Control Mode [NETCONF-ACM] rules are required to configure or retrieve them. The clear-text algorithm is included as a YANG feature. Usage is NOT RECOMMENDED except in cases where the application and device have no other alternative (e.g., a legacy network device that must authenticate packets at intervals of 10 milliseconds or less for many peers using Bidirectional Forwarding Detection [BFD]). Keys used with the clear-text algorithm are considered insecure and SHOULD NOT be reused with more secure algorithms. Lindem, et al. Expires October 28, 2017 [Page 15] Internet-Draft YANG Key Chain April 2017 Similarly, the MD5 and SHA-1 algorithms have been proven to be insecure ([Dobb96a], [Dobb96b], and [SHA-SEC-CON]) and usage is NOT RECOMMENDED. Usage should be confined to deployments where it is required for backward compatibility. It is RECOMMENDED that keys be encrypted or otherwise obfuscated when stored internally on a network device supporting this specification. 6. IANA Considerations This document registers a URI in the IETF XML registry [XML-REGISTRY]. Following the format in [XML-REGISTRY], the following registration is requested to be made: URI: urn:ietf:params:xml:ns:yang:ietf-key-chain Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace. This document registers a YANG module in the YANG Module Names registry [YANG]. name: ietf-key-chain namespace: urn:ietf:params:xml:ns:yang:ietf-key-chain prefix: key-chain reference: RFC XXXX 7. Contributors Contributors' Addresses Yi Yang SockRate Email: yi.yang@sockrate.com 8. References 8.1. Normative References [NETCONF] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011. [NETCONF-ACM] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, March 2012. Lindem, et al. Expires October 28, 2017 [Page 16] Internet-Draft YANG Key Chain April 2017 [RFC-KEYWORDS] Bradner, S., "Key words for use in RFC's to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [XML-REGISTRY] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [YANG] Bjorklund, M., "The YANG 1.1 Data Modeling Language", RFC 7950, August 2016. 8.2. Informative References [BFD] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, June 2010. [CRYPTO-KEYTABLE] Housley, R., Polk, T., Hartman, S., and D. Zhang, "Table of Cryptographic Keys", RFC 7210, April 2014. [Dobb96a] Dobbertin, H., "Cryptanalysis of MD5 Compress", Technical Report (Presented at the RUMP Session of EuroCrypt 1996), 2 May 1996. [Dobb96b] Dobbertin, H., "The Status of MD5 After a Recent Attack", CryptoBytes Vol. 2, No. 2, Summer 1996. [IAB-REPORT] Andersson, L., Davies, E., and L. Zhang, "Report from the IAB workshop on Unwanted Traffic March 9-10, 2006", RFC 4948, August 2007. [NETCONF-SSH] Wasserman, M., "NETCONF over SSH", RFC 6242, June 2011. [NMDA] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watson, K., and R. Wilton, "Network Management Datastore Architecture", draft-ietf-netmod-revised-datastores-01.txt (work in progress), March 2017. [NTP-PROTO] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network Time Protocol Version 4: Protocol and Algorithms Specification", RFC 5905, June 2010. [OSPFV3-AUTH] Bhatia, M., Manral, V., and A. Lindem, "Supporting Authentication Trailer for OSPFv3", RFC 7166, March 2014. Lindem, et al. Expires October 28, 2017 [Page 17] Internet-Draft YANG Key Chain April 2017 [RESTCONF] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, January 2017. [SHA-SEC-CON] Polk, T., Chen, L., Turner, S., and P. Hoffman, "Security Considerations for the SHA-0 and SHA-1 Message-Digest Algorithms", RFC 6194, February 2011. [TCP-AO] Touch, J., Mankin, A., and R. Bonica, "The TCP Authentication Option", RFC 5925, June 2010. [TCP-AO-ALGORITHMS] Lebovitz, G. and E. Rescorla, "Cryptographic Algorithms for the TCP Authentication Option (TCP-AO)", RFC 5926, June 2010. [TLS] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol", RFC 5246, August 2008. [YANG-CRYPTO-KEYTABLE] Chen, I., "YANG Data Model for RFC 7210 Key Table", draft- chen-rtg-key-table-yang-00.txt (work in progress), November 2015. Appendix A. Examples Lindem, et al. Expires October 28, 2017 [Page 18] Internet-Draft YANG Key Chain April 2017 A.1. Simple Key Chain with Always Valid Single Key keychain-no-end-time A key chain with a single key that is always valid for tx/rx 100 hmac-sha-256 keystring_in_ascii_100 A.2. Key Chain with Keys having Different Lifetimes Lindem, et al. Expires October 28, 2017 [Page 19] Internet-Draft YANG Key Chain April 2017 keychain2 A key chain where each key contains a different send time and accept time and a different algorithm illustrating algorithm agility 35 2017-01-01T00:00:00Z 2017-02-01T00:00:00Z 2016-12-31T23:59:55Z 2017-02-01T00:00:05Z hmac-sha-256 keystring_in_ascii_35 36 2017-02-01T00:00:00Z 2017-03-01T00:00:00Z 2017-01-31T23:59:55Z 2017-03-01T00:00:05Z hmac-sha-512 fe:ed:be:af:36 Lindem, et al. Expires October 28, 2017 [Page 20] Internet-Draft YANG Key Chain April 2017 A.3. Key Chain with Independent Send and Accept Lifetimes keychain2 A key chain where each key contains different send time and accept time 35 2017-01-01T00:00:00Z 2017-02-01T00:00:00Z 2016-12-31T23:59:55Z 2017-02-01T00:00:05Z hmac-sha-256 keystring_in_ascii_35 36 2017-02-01T00:00:00Z 2017-03-01T00:00:00Z 2017-01-31T23:59:55Z 2017-03-01T00:00:05Z hmac-sha-256 fe:ed:be:af:36 Lindem, et al. Expires October 28, 2017 [Page 21] Internet-Draft YANG Key Chain April 2017 Appendix B. Acknowledgments The RFC text was produced using Marshall Rose's xml2rfc tool. Thanks to Brian Weis for fruitful discussions on security requirements. Thanks to Ines Robles for Routing Directorate QA review comments. Thanks to Ladislav Lhotka for YANG Doctor comments. Thanks to Martin Bjorklund for additional YANG Doctor comments. Thanks to Tom Petch for comments during IETF last call. Thanks to Matthew Miller for comments made during the Gen-ART review. Thanks to Vincent Roca for comments made during the Security Directorate review. Thanks to Warren Kumari, Ben Campbell, Adam Roach, and Benoit Claise for comments received during the IESG review. Authors' Addresses Acee Lindem (editor) Cisco Systems 301 Midenhall Way Cary, NC 27513 USA Email: acee@cisco.com Yingzhen Qu Huawei Email: yingzhen.qu@huawei.com Derek Yeung Arrcus, Inc Email: derek@arrcus.com Lindem, et al. Expires October 28, 2017 [Page 22] Internet-Draft YANG Key Chain April 2017 Ing-Wher Chen Jabil Email: ing-wher_chen@jabil.com Jeffrey Zhang Juniper Networks 10 Technology Park Drive Westford, MA 01886 USA Email: zzhang@juniper.net Lindem, et al. Expires October 28, 2017 [Page 23]