Network Working Group G. Zorn Internet-Draft Cisco Systems Updates: 2865, 2866, 3576, 3579 T. Zhang (if approved) 3e Technologies International Expires: August 24, 2006 J. Walker Intel Corporation J. Salowey Cisco Systems February 20, 2006 RADIUS Attributes for Key Delivery draft-zorn-radius-keywrap-09.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 24, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This document defines a set of RADIUS Attributes designed to allow both the secure transmission of encryption keys and strong authentication of any RADIUS message. Zorn, et al. Expires August 24, 2006 [Page 1] Internet-Draft RADIUS Attributes for Key Delivery February 2006 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Specification of Requirements . . . . . . . . . . . . . . . 3 3. Attributes . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1 Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2 Random-Nonce . . . . . . . . . . . . . . . . . . . . . . . 7 3.3 Message-Authentication-Code . . . . . . . . . . . . . . . 8 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . 12 5. Attribute Types . . . . . . . . . . . . . . . . . . . . . . 12 6. Attribute Values . . . . . . . . . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . 12 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 10.1 Normative References . . . . . . . . . . . . . . . . . . 13 10.2 Informative References . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 15 Intellectual Property and Copyright Statements . . . . . . . 16 Zorn, et al. Expires August 24, 2006 [Page 2] Internet-Draft RADIUS Attributes for Key Delivery February 2006 1. Introduction Many remote access deployments (for example, deployments utilizing wireless LAN technology) require the secure transmission of session keys from an authentication server to a network access point. Currently, this transfer is most often accomplished using vendor- specific RADIUS attributes [RFC2548], with the integrity of the message protected by the RADIUS Response Authenticator [RFC2865], the Request and Response Authenticators (in the cases of RADIUS Accounting [RFC2866] and Dynamic Authorization [RFC3576]) or the Message-Authenticator Attribute [RFC3579]. However, there are several issues with these techniques: o The key transport attributes were designed for use with a specific, proprietary protocol [RFC3078] and may be inappropriate for other uses o The security properties and strength of the encryption method used to hide the keys are unknown o The hash function ([RFC1321]) used in the construction of the Response Authenticator is proprietary and the construct itself is weaker than more modern methods (e.g., HMAC [RFC2104]) o The Message-Authenticator Attribute is unusable in some situations where strong message authentication might be required This document defines a set of RADIUS Attributes that can be used to securely transfer encryption keys using non-proprietary techniques with well understood security properties. In addition, the Message- Authentication-Code Attribute may be used to provide strong authentication for any RADIUS message, including those used for accounting and dynamic authorization. Discussion of this draft may be directed to the authors. 2. Specification of Requirements 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 [RFC2119]. 3. Attributes The following subsections describe the Attributes defined by this document. This specification concerns the following values: Zorn, et al. Expires August 24, 2006 [Page 3] Internet-Draft RADIUS Attributes for Key Delivery February 2006 [TBD1] Key [TBD2] Random-Nonce [TBD3] Message-Authentication-Code 3.1 Key Description This Attribute MAY be used to carry an encryption key from a RADIUS server to a client. It MAY be sent in request messages (e.g., Access-Request, etc.), as well; if the Key Attribute is present in a request, it SHOULD be taken as a hint by the server that the client prefers this method of key delivery over others, the server is not obligated to honor the hint, however. When the Key Attribute is included in a request message the Key ID, Lifetime, IV and Key Data fields MAY be omitted (i.e., zero-filled) before transmission. If the client requires the use of the Key Attribute for key delivery and it is not present in the Access-Accept or Access- Challenge message, the client MAY ignore the message in question and end the user session. Any packet that contains a Key Attribute MUST also include the Message-Authentication-Code Attribute. Any packet that contains an instance of the Key Attribute MUST NOT contain an instance of any other key transport attribute (e.g., MS-CHAP-MPPE-Keys [RFC2548], Tunnel-Password [RFC2868], etc.) encapsulating identical keying material. The Key Attribute MUST NOT be used to transfer long-lived keys (i.e., passwords) between RADIUS servers and clients. A summary of the Key attribute format is shown below. The fields are transmitted from left to right. Zorn, et al. Expires August 24, 2006 [Page 4] Internet-Draft RADIUS Attributes for Key Delivery February 2006 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Reserved | Enc Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | App ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | KEK ID +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ KEK ID (cont'd) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ KEK ID (cont'd) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ KEK ID (cont'd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Key ID +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Key ID (cont'd) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Key ID (cont'd) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Key ID (cont'd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IV +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IV (cont'd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Key Data... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type [TBD1] for Key Length >= 3 Reserved This field is reserved for future usage and MUST be zero- filled. Zorn, et al. Expires August 24, 2006 [Page 5] Internet-Draft RADIUS Attributes for Key Delivery February 2006 Enc Type The Enc Type field indicates the method used to encrypt the key that is carried in the Key Data field. This document defines only one value (decimal) for this field: 0 AES Key Wrap with 128-bit KEK [RFC3394] Implementations MUST support Enc Type 0 (AES Key Wrap with 128- bit KEK); other values are to be assigned by IANA. Implementation Note A shared secret is used as the key-encrypting-key (KEK) for the AES key wrap algorithm. Implementations SHOULD provide a means to provision a key (cryptographically separate from the normal RADIUS shared secret) to be used exclusively as a KEK. App ID The App ID field is 4 octets in length and identifies the type of application for which the key is to be used. This allows for multiple keys for different purposes to be present in the same message. This document defines two values for the App ID: 0 Unspecified 1 EAP MSK Other values are to be assigned by IANA; further specification of the content of this field is outside the scope of this document. KEK ID The KEK ID field is 16 octets in length and contains an identifier for the KEK. The KEK ID MUST refer to a encryption key of a type and length appropriate for use with the algorithm specified by the Enc Type field (see above). This key is used to protect the contents of the Key Data field (below). Further specification of the content of this field is outside the scope of this document. Key ID The Key ID field is 16 octets in length and contains an identifier for the key. The Key ID MAY be used by Zorn, et al. Expires August 24, 2006 [Page 6] Internet-Draft RADIUS Attributes for Key Delivery February 2006 communicating parties to identify the key that is being transmitted. The combination of App ID and Key ID MUST uniquely identify the key between the parties utilizing the key. The Key ID is assumed to be known to the parties that derived the key. Further specification of the content of this field is outside the scope of this document. Lifetime The Lifetime field is an integer [RFC2865] representing the period of time (in seconds) for which the keying material is valid. Note: Applications using this value SHOULD consider the beginning of the key lifetime to be the point in time when the key is first used for either encryption or decryption. IV The length of the IV field depends upon the value of the Enc Type field, but is fixed for any given value thereof. When the value of the Enc Type field is 0 (decimal), the IV field MUST be 8 octets in length (as illustrated above) and the value of the IV field MUST be as specified in [RFC3394]. Key Data The Key Data field is variable length and contains the actual encrypted keying material. 3.2 Random-Nonce Description The Random-Nonce Attribute MUST be present in any message that includes an instance of the Message-Authentication-Code Attribute. The Random field MUST contain a 32 octet random number which SHOULD satisfy the requirements of [RFC4086]. Implementation Note The Random field MUST be filled in before the MAC is computed. A summary of the Random-Nonce attribute format is shown below. The fields are transmitted from left to right. Zorn, et al. Expires August 24, 2006 [Page 7] Internet-Draft RADIUS Attributes for Key Delivery February 2006 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Random... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type [TBD2] for Random-Nonce Length 34 Random This field MUST contain a 32 octet random number which SHOULD satisfy the requirements of [RFC4086]. 3.3 Message-Authentication-Code Description This Attribute MAY be used to "sign" messages to prevent spoofing If it is present in a request, the receiver should take this a hint that the sender prefers the use of this Attribute for message authentication; the receiver is not obligated to do so, however. The Message-Authentication-Code Attribute MUST be included in any message that contains a Key attribute. Any packet that contains an instance of the Message- Authentication-Code Attribute SHOULD NOT contain an instance of the Message-Authenticator Attribute [RFC3579]. If both attributes are to be included in a message (e.g., for backward compatibility in a network containing both old and new clients), the value of the Message-Authentication-Code Attribute MUST be computed as follows: when sending a message, the value of the Message- Authentication-Code Attribute MUST be computed first and that value used to compute the value of the Message-Authenticator Attribute. If any message is received containing an instance of the Message- Authentication-Code Attribute, the receiver MUST calculate the correct value of the Message-Authentication-Code and silently Zorn, et al. Expires August 24, 2006 [Page 8] Internet-Draft RADIUS Attributes for Key Delivery February 2006 discard the packet if the computed value does not match the value received. If a received message contains an instance of the Random-Nonce Attribute (Section 3.2), the received Random-Nonce Attribute SHOULD be included in the computation of the Message- Authentication-Code Attribute sent in the response, as described below. A summary of the Message-Authentication-Code attribute format is shown below. The fields are transmitted from left to right. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Reserved | MAC Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Key ID +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MAC Key ID (cont'd) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MAC Key ID (cont'd) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MAC Key ID (cont'd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type [TBD3] for Message-Authentication-Code Length >3 Reserved This field is reserved for future usage and MUST be zero- filled. MAC Type The MAC Type field specifies the algorithm used to create the value in the MAC field. This document defines six values for Zorn, et al. Expires August 24, 2006 [Page 9] Internet-Draft RADIUS Attributes for Key Delivery February 2006 the MAC Type field: 0 HMAC-SHA-1 [FIPS.180-2.2002] [RFC2104] 1 HMAC-SHA-256 [FIPS.180-2.2002] [RFC2104] 2 HMAC-SHA-512 [FIPS.180-2.2002] [RFC2104] 3 CMAC-AES-128 [NIST.SP800-38B] 4 CMAC-AES-192 [NIST.SP800-38B] 5 CMAC-AES-256 [NIST.SP800-38B] Implementations MUST support MAC Type 0 (HMAC-SHA-1); other values are to be assigned by IANA. MAC Key ID The MAC Key ID field is 16 octets in length and contains an identifier for the key. The MAC Key ID MUST refer to a key of a type and length appropriate for use with the algorithm specified by the MAC Type field (see above). Further specification of the content of this field is outside the scope of this document. MAC Both the length and value of the MAC field depend upon the algorithm specified by the value of the MAC Type field. If the algorithm specified is HMAC-SHA-1, HMAC-SHA-256 or HMAC-SHA- 512, the MAC field MUST be 20, 32 or 64 octets in length, respectively. If the algorithm specified is CMAC-AES-128, CMAC-AES-192 or CMAC-AES-256, the MAC field SHOULD be 64 octets in length. The derivation of the MAC field value for all the algorithms specified in this document is identical, except for the algorithm used. There are differences, however, depending upon whether the MAC is being computed for a request message or a response. These differences are detailed below, with the free variable HASH-ALG representing the actual algorithm used. Request Messages For requests (e.g., CoA-Request [RFC3576], Accounting- Request [RFC2866], etc.), the value of the MAC field is a hash of the entire packet except the Request Authenticator, using a shared secret as the key, as follows. Zorn, et al. Expires August 24, 2006 [Page 10] Internet-Draft RADIUS Attributes for Key Delivery February 2006 MAC = HASH-ALG(Type, Identifier, Length, Attributes) The Random-Nonce Attribute (Section 3.2) MUST be included in any request in which the Message-Authentication-Code Attribute is used. The Random field of the Random-Nonce Attribute MUST be filled in before the value of the MAC field is computed. If the Message-Authenticator-Code Attribute is included in a client request, the server SHOULD ignore the contents of the Request Authenticator. Implementation Notes When the hash is calculated, both the MAC field and the String field of the Message-Authenticator Attribute (if any) MUST be considered to be zero-filled. Implementations SHOULD provide a means to provision a key (cryptographically separate from the normal RADIUS shared secret) to be used exclusively in the generation of the Message-Authentication-Code. Response Messages For responses (e.g., CoA-ACK [RFC3576], Accounting-Response [RFC2866], etc.), the value of the MAC field is a hash of the entire packet except the Response Authenticator using a shared secret as the key, as follows. MAC = HASH-ALG(Type, Identifier, Length, Attributes) If the request contained an instance of the Random-Nonce Attribute and the responder wishes to include an instance of the Message-Authentication-Code Attribute in the corresponding response, then the Random-Nonce Attribute from the request MUST be included in the response. If the Message-Authenticator-Code Attribute is included in a server response, the client SHOULD ignore the contents of the Response Authenticator. Implementation Notes When the hash is calculated, both the MAC field and the String field of the Message-Authenticator Attribute (if any) MUST be considered to be zero-filled. Zorn, et al. Expires August 24, 2006 [Page 11] Internet-Draft RADIUS Attributes for Key Delivery February 2006 The Message-Authentication-Code Attribute MUST be created and inserted in the packet before the Response Authenticator is calculated. Implementations SHOULD provide a means to provision a key (cryptographically separate from the normal RADIUS shared secret) to be used exclusively in the generation of the Message-Authentication-Code. 4. IANA Considerations This section explains the criteria to be used by the IANA for assignment of numbers within namespaces defined within this document. The "Specification Required" policy is used here with the meaning defined in BCP 26 [RFC2434]. 5. Attribute Types Upon publication of this document as an RFC, IANA must assign numbers to the Key [TBD1], Random-Nonce [TBD2] and Message- Authentication-Code [TBD3] Attributes. 6. Attribute Values As defined in Section 3.1, numbers may need to be assigned for future values of the Enc Type field of the Key attribute. These numbers may be assigned by applying the "Specification Required" policy. In particular, specifications MUST define the length of the IV field for the algorithm used. As defined in Section 3.2, numbers may need to be assigned for future values of the MAC Type field of the Message-Authentication-Code attribute. These numbers may be assigned by applying the "Specification Required" policy. As defined in Section 3.2, numbers may need to be assigned for future values of the App Type field of the Message-Authentication-Code attribute. These numbers may be assigned by applying the "First Come First Served" policy. 7. Security Considerations It is RECOMMENDED in this memo that two new keys be shared by the RADIUS client and server. If implemented, these two keys MUST be different from each other and SHOULD NOT be based on a password. These two keys SHOULD be cryptographically independent of the RADIUS shared secret used in calculating the Response Authenticator Zorn, et al. Expires August 24, 2006 [Page 12] Internet-Draft RADIUS Attributes for Key Delivery February 2006 [RFC2865], Request Authenticator [RFC2866] [RFC3576] and Message- Authenticator Attribute [RFC3579]; otherwise if the shared secret is broken, all is lost. To avoid the possibility of collisions, the MAC key SHOULD NOT be used with more than 2^64 messages. If a packet that contains an instance of the Key Attribute also contains an instance of another, weaker key transport attribute (e.g., MS-MPPE-Recv-Key [RFC2548]) encapsulating identical keying material, then breaking the weaker attribute might facilitate a known-plaintext attack against the KEK. 8. Contributors Hao Zhou, Nancy Cam-Winget, Paul Funk and John Fossaceca all contributed to this document. 9. Acknowledgements Thanks (in no particular order) to Keith McCloghrie, Kaushik Narayan, Murtaza Chiba, Bill Burr, Russ Housley, David McGrew, Pat Calhoun and Greg Weber for useful feedback. 10. References 10.1 Normative References [FIPS.180-2.2002] National Institute of Standards and Technology, "Secure Hash Standard", FIPS PUB 180-2, August 2002, . [NIST.SP800-38B] Dworkin, M., "Recommendation for Block Cipher Modes of Operation: The CMAC Mode for Authentication", May 2005, . [RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, April 1992. [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- Hashing for Message Authentication", RFC 2104, February 1997. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Zorn, et al. Expires August 24, 2006 [Page 13] Internet-Draft RADIUS Attributes for Key Delivery February 2006 Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. [RFC2866] Rigney, C., "RADIUS Accounting", RFC 2866, June 2000. [RFC2868] Zorn, G., Leifer, D., Rubens, A., Shriver, J., Holdrege, M., and I. Goyret, "RADIUS Attributes for Tunnel Protocol Support", RFC 2868, June 2000. [RFC3394] Schaad, J. and R. Housley, "Advanced Encryption Standard (AES) Key Wrap Algorithm", RFC 3394, September 2002. [RFC3575] Aboba, B., "IANA Considerations for RADIUS (Remote Authentication Dial In User Service)", RFC 3575, July 2003. [RFC3576] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B. Aboba, "Dynamic Authorization Extensions to Remote Authentication Dial In User Service (RADIUS)", RFC 3576, July 2003. [RFC3579] Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication Dial In User Service) Support For Extensible Authentication Protocol (EAP)", RFC 3579, September 2003. [RFC4086] Eastlake, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", BCP 106, RFC 4086, June 2005. 10.2 Informative References [RFC2548] Zorn, G., "Microsoft Vendor-specific RADIUS Attributes", RFC 2548, March 1999. [RFC3078] Pall, G. and G. Zorn, "Microsoft Point-To-Point Encryption (MPPE) Protocol", RFC 3078, March 2001. Zorn, et al. Expires August 24, 2006 [Page 14] Internet-Draft RADIUS Attributes for Key Delivery February 2006 Authors' Addresses Glen Zorn Cisco Systems 2901 Third Avenue, Suite 600 SEA1/5/ Seattle, WA 98121 US Phone: +1 (425) 344 8113 Email: gwz@cisco.com Tiebing Zhang 3e Technologies International 700 King Farm Blvd. Rockville, MD 20850 US Phone: +1 (301) 944-1322 Email: tzhang@3eti.com Jesse Walker Intel Corporation JF3-206 2111 N.E. 25th Ave Hillsboro, OR 97214-5961 US Phone: +1 (503) 712-1849 Email: jesse.walker@intel.com Joseph Salowey Cisco Systems 2901 Third Avenue SEA1/6/ Seattle, WA 98121 US Phone: +1 (206) 256-3380 Email: jsalowey@cisco.com Zorn, et al. Expires August 24, 2006 [Page 15] Internet-Draft RADIUS Attributes for Key Delivery February 2006 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Zorn, et al. Expires August 24, 2006 [Page 16]