draft-ietf-dnsext-tsig-sha-06.txt   rfc4635.txt 
INTERNET-DRAFT Donald E. Eastlake 3rd Network Working Group D. Eastlake 3rd
UPDATES RFC 2845 Motorola Laboratories Request for Comments: 4635 Motorola Laboratories
Expires: July 2006 January 2006 Category: Standards Track August 2006
HMAC SHA TSIG Algorithm Identifiers HMAC SHA TSIG Algorithm Identifiers
---- --- ---- --------- -----------
<draft-ietf-dnsext-tsig-sha-06.txt>
Status of This Document
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Abstract Abstract
Use of the Domain Name System TSIG resource record requires Use of the Domain Name System TSIG resource record requires
specification of a cryptographic message authentication code. specification of a cryptographic message authentication code.
Currently identifiers have been specified only for the HMAC MD5 Currently, identifiers have been specified only for HMAC MD5 (Hashed
(Message Digest) and GSS (Generic Security Service) TSIG algorithms. Message Authentication Code, Message Digest 5) and GSS (Generic
This document standardizes identifiers and implementation Security Service) TSIG algorithms. This document standardizes
requirements for additional HMAC SHA (Secure Hash Algorithm) TSIG identifiers and implementation requirements for additional HMAC SHA
algorithms and standardizes how to specify and handle the truncation (Secure Hash Algorithm) TSIG algorithms and standardizes how to
of HMAC values in TSIG. specify and handle the truncation of HMAC values in TSIG.
Copyright Notice
Copyright (C) The Internet Society (2006).
INTERNET-DRAFT HMAC-SHA TSIG Identifiers
Table of Contents Table of Contents
Status of This Document....................................1 1. Introduction ....................................................2
Abstract...................................................1 2. Algorithms and Identifiers ......................................2
Copyright Notice...........................................1 3. Specifying Truncation ...........................................3
3.1. Truncation Specification ...................................4
Table of Contents..........................................2 4. TSIG Truncation Policy and Error Provisions .....................4
5. IANA Considerations .............................................5
1. Introduction............................................3 6. Security Considerations .........................................5
7. Normative References ............................................6
2. Algorithms and Identifiers..............................4 8. Informative References. .........................................7
3. Specifying Truncation...................................5
3.1 Truncation Specification...............................5
4. TSIG Truncation Policy and Error Provisions.............6
5. IANA Considerations.....................................7
6. Security Considerations.................................7
7. Copyright and Disclaimer................................7
8. Normative References....................................8
9. Informative References..................................8
Author's Address...........................................9
Additional IPR Provisions..................................9
Expiration and File Name...................................9
INTERNET-DRAFT HMAC-SHA TSIG Identifiers
1. Introduction 1. Introduction
[RFC 2845] specifies a TSIG Resource Record (RR) that can be used to [RFC 2845] specifies a TSIG Resource Record (RR) that can be used to
authenticate DNS (Domain Name System [STD 13]) queries and responses. authenticate DNS (Domain Name System [STD 13]) queries and responses.
This RR contains a domain name syntax data item which names the This RR contains a domain name syntax data item that names the
authentication algorithm used. [RFC 2845] defines the HMAC-MD5.SIG- authentication algorithm used. [RFC2845] defines the
ALG.REG.INT name for authentication codes using the HMAC [RFC 2104] HMAC-MD5.SIG-ALG.REG.INT name for authentication codes using the HMAC
algorithm with the MD5 [RFC 1321] hash algorithm. IANA has also (Hashed Message Authentication Code) [RFC2104] algorithm with the MD5
(Message Digest 5) [RFC1321] hash algorithm. IANA has also
registered "gss-tsig" as an identifier for TSIG authentication where registered "gss-tsig" as an identifier for TSIG authentication where
the cryptographic operations are delegated to the Generic Security the cryptographic operations are delegated to the Generic Security
Service (GSS) [RFC 3645]. Service (GSS) [RFC 3645].
It should be noted that use of TSIG presumes prior agreement, between Note that use of TSIG presumes prior agreement, between the resolver
the resolver and server involved, as to the algorithm and key to be and server involved, as to the algorithm and key to be used.
used.
In Section 2, this document specifies additional names for TSIG In Section 2, this document specifies additional names for TSIG
authentication algorithms based on US NIST SHA (United States, authentication algorithms based on US NIST SHA (United States,
National Institute of Science and Technology, Secure Hash Algorithm) National Institute of Science and Technology, Secure Hash Algorithm)
algorithms and HMAC and specifies the implementation requirements for algorithms and HMAC and specifies the implementation requirements for
those algorithms. those algorithms.
In Section 3, this document specifies the effect of inequality In Section 3, this document specifies the effect of inequality
between the normal output size of the specified hash function and the between the normal output size of the specified hash function and the
length of MAC (message authentication code) data given in the TSIG length of MAC (Message Authentication Code) data given in the TSIG
RR. In particular, it specifies that a shorter length field value RR. In particular, it specifies that a shorter-length field value
specifies truncation and a longer length field is an error. specifies truncation and that a longer-length field is an error.
In Section 4, policy restrictions and implications related to In Section 4, policy restrictions and implications related to
truncation and a new error code to indicate truncation shorter than truncation are described and specified, as is a new error code to
permitted by policy are described and specified. indicate truncation shorter than that permitted by policy.
The use herein of MUST, SHOULD, MAY, MUST NOT, and SHOULD NOT is as
defined in [RFC 2119].
INTERNET-DRAFT HMAC-SHA TSIG Identifiers The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", "MAY", in
this document are to be interpreted as described in [RFC2119].
2. Algorithms and Identifiers 2. Algorithms and Identifiers
TSIG Resource Records (RRs) [RFC 2845] are used to authenticate DNS TSIG Resource Records (RRs) [RFC 2845] are used to authenticate DNS
queries and responses. They are intended to be efficient symmetric queries and responses. They are intended to be efficient symmetric
authentication codes based on a shared secret. (Asymmetric signatures authentication codes based on a shared secret. (Asymmetric
can be provided using the SIG RR [RFC 2931]. In particular, SIG(0) signatures can be provided using the SIG RR [RFC2931]. In
can be used for transaction signatures.) Used with a strong hash particular, SIG(0) can be used for transaction signatures.) Used
function, HMAC [RFC 2104] provides a way to calculate such symmetric with a strong hash function, HMAC [RFC2104] provides a way to
authentication codes. The only specified HMAC based TSIG algorithm calculate such symmetric authentication codes. The only specified
identifier has been HMAC-MD5.SIG-ALG.REG.INT based on MD5 [RFC 1321]. HMAC-based TSIG algorithm identifier has been HMAC-MD5.SIG-
ALG.REG.INT, based on MD5 [RFC1321].
The use of SHA-1 [FIPS 180-2, RFC 3174], which is a 160 bit hash, as The use of SHA-1 [FIPS180-2, RFC3174], which is a 160-bit hash, as
compared with the 128 bits for MD5, and additional hash algorithms in compared with the 128 bits for MD5, and additional hash algorithms in
the SHA family [FIPS 180-2, RFC 3874, SHA2draft] with 224, 256, 384, the SHA family [FIPS180-2, RFC3874, RFC4634] with 224, 256, 384, and
and 512 bits, may be preferred in some cases particularly since 512 bits may be preferred in some cases. This is because
increasingly successful cryptanalytic attacks are being made on the increasingly successful cryptanalytic attacks are being made on the
shorter hashes. shorter hashes.
Use of TSIG between a DNS resolver and server is by mutual agreement. Use of TSIG between a DNS resolver and server is by mutual agreement.
That agreement can include the support of additional algorithms and That agreement can include the support of additional algorithms and
criteria as to which algorithms and truncations are acceptable, criteria as to which algorithms and truncations are acceptable,
subject to the restriction and guidelines in Section 3 and 4 below. subject to the restriction and guidelines in Sections 3 and 4 below.
Key agreement can be by the TKEY mechanism [RFC 2930] or other Key agreement can be by the TKEY mechanism [RFC2930] or some other
mutually agreeable method. mutually agreeable method.
The current HMAC-MD5.SIG-ALG.REG.INT and gss-tsig identifiers are The current HMAC-MD5.SIG-ALG.REG.INT and gss-tsig identifiers are
included in the table below for convenience. Implementations which included in the table below for convenience. Implementations that
support TSIG MUST also implement HMAC SHA1 and HMAC SHA256 and MAY support TSIG MUST also implement HMAC SHA1 and HMAC SHA256 and MAY
implement gss-tsig and the other algorithms listed below. implement gss-tsig and the other algorithms listed below.
Mandatory HMAC-MD5.SIG-ALG.REG.INT Mandatory HMAC-MD5.SIG-ALG.REG.INT
Optional gss-tsig Optional gss-tsig
Mandatory hmac-sha1 Mandatory hmac-sha1
Optional hmac-sha224 Optional hmac-sha224
Mandatory hmac-sha256 Mandatory hmac-sha256
Optional hamc-sha384 Optional hamc-sha384
Optional hmac-sha512 Optional hmac-sha512
SHA-1 truncated to 96 bits (12 octets) SHOULD be implemented. SHA-1 truncated to 96 bits (12 octets) SHOULD be implemented.
INTERNET-DRAFT HMAC-SHA TSIG Identifiers
3. Specifying Truncation 3. Specifying Truncation
When space is at a premium and the strength of the full length of an When space is at a premium and the strength of the full length of an
HMAC is not needed, it is reasonable to truncate the HMAC output and HMAC is not needed, it is reasonable to truncate the HMAC output and
use the truncated value for authentication. HMAC SHA-1 truncated to use the truncated value for authentication. HMAC SHA-1 truncated to
96 bits is an option available in several IETF protocols including 96 bits is an option available in several IETF protocols, including
IPSEC and TLS. IPsec and TLS.
The TSIG RR [RFC 2845] includes a "MAC size" field, which gives the The TSIG RR [RFC 2845] includes a "MAC size" field, which gives the
size of the MAC field in octets. But [RFC 2845] does not specify what size of the MAC field in octets. However, [RFC2845] does not specify
to do if this MAC size differs from the length of the output of HMAC what to do if this MAC size differs from the length of the output of
for a particular hash function. Truncation is indicated by a MAC size HMAC for a particular hash function. Truncation is indicated by a
less than the HMAC size as specified below. MAC size less than the HMAC size, as specified below.
3.1 Truncation Specification 3.1. Truncation Specification
The specification for TSIG handling is changed as follows: The specification for TSIG handling is changed as follows:
1. If "MAC size" field is greater than HMAC output length: 1. If "MAC size" field is greater than HMAC output length:
This case MUST NOT be generated and if received MUST cause the
packet to be dropped and RCODE 1 (FORMERR) to be returned. This case MUST NOT be generated and, if received, MUST cause
the packet to be dropped and RCODE 1 (FORMERR) to be returned.
2. If "MAC size" field equals HMAC output length: 2. If "MAC size" field equals HMAC output length:
Operation is as described in [RFC 2845] with the entire output
HMAC output present. Operation is as described in [RFC2845], and the entire output
HMAC output is present.
3. "MAC size" field is less than HMAC output length but greater than 3. "MAC size" field is less than HMAC output length but greater than
that specified in case 4 below: that specified in case 4, below:
This is sent when the signer has truncated the HMAC output to This is sent when the signer has truncated the HMAC output to
an allowable length, as described in RFC 2104, taking initial an allowable length, as described in RFC 2104, taking initial
octets and discarding trailing octets. TSIG truncation can only be octets and discarding trailing octets. TSIG truncation can only
to an integral number of octets. On receipt of a packet with be to an integral number of octets. On receipt of a packet with
truncation thus indicated, the locally calculated MAC is similarly truncation thus indicated, the locally calculated MAC is similarly
truncated and only the truncated values compared for truncated and only the truncated values are compared for
authentication. The request MAC used when calculating the TSIG MAC authentication. The request MAC used when calculating the TSIG
for a reply is the truncated request MAC. MAC for a reply is the truncated request MAC.
4. "MAC size" field is less than the larger of 10 (octets) and half 4. "MAC size" field is less than the larger of 10 (octets) and half
the length of the hash function in use: the length of the hash function in use:
With the exception of certain TSIG error messages described in With the exception of certain TSIG error messages described in
RFC 2845 section 3.2 where it is permitted that the MAC size be RFC 2845, Section 3.2, where it is permitted that the MAC size be
zero, this case MUST NOT be generated and if received MUST cause zero, this case MUST NOT be generated and, if received, MUST cause
the packet to be dropped and RCODE 1 (FORMERR) to be returned. The the packet to be dropped and RCODE 1 (FORMERR) to be returned.
size limit for this case can also, for the hash functions The size limit for this case can also, for the hash functions
mentioned in this document, be stated as less than half the hash mentioned in this document, be stated as less than half the hash
function length for hash functions other than MD5 and less than 10 function length for hash functions other than MD5 and less than 10
octets for MD5. octets for MD5.
INTERNET-DRAFT HMAC-SHA TSIG Identifiers
4. TSIG Truncation Policy and Error Provisions 4. TSIG Truncation Policy and Error Provisions
Use of TSIG is by mutual agreement between a resolver and server. Use of TSIG is by mutual agreement between a resolver and server.
Implicit in such "agreement" are criterion as to acceptable keys and Implicit in such "agreement" are criterion as to acceptable keys and
algorithms and, with the extensions in this document, truncations. algorithms and, with the extensions in this document, truncations.
Note that it is common for implementations to bind the TSIG secret Note that it is common for implementations to bind the TSIG secret
key or keys that may be in place at a resolver and server to key or keys that may be in place at a resolver and server to
particular algorithms. Thus such implementations only permit the use particular algorithms. Thus, such implementations only permit the
of an algorithm if there is an associated key in place. Receipt of an use of an algorithm if there is an associated key in place. Receipt
unknown, unimplemented, or disabled algorithm typically results in a of an unknown, unimplemented, or disabled algorithm typically results
BADKEY error. in a BADKEY error.
Local policies MAY require the rejection of TSIGs even though they Local policies MAY require the rejection of TSIGs, even though
use an algorithm for which implementation is mandatory. they use an algorithm for which implementation is mandatory.
When a local policy permits acceptance of a TSIG with a particular When a local policy permits acceptance of a TSIG with a particular
algorithm and a particular non-zero amount of truncation it SHOULD algorithm and a particular non-zero amount of truncation, it SHOULD
also permit the use of that algorithm with lesser truncation (a also permit the use of that algorithm with lesser truncation (a
longer MAC) up to the full HMAC output. longer MAC) up to the full HMAC output.
Regardless of a lower acceptable truncated MAC length specified by Regardless of a lower acceptable truncated MAC length specified by
local policy, a reply SHOULD be sent with a MAC at least as long as local policy, a reply SHOULD be sent with a MAC at least as long as
that in the corresponding request unless the request specified a MAC that in the corresponding request, unless the request specified a MAC
length longer than the HMAC output. length longer than the HMAC output.
Implementations permitting multiple acceptable algorithms and/or Implementations permitting multiple acceptable algorithms and/or
truncations SHOULD permit this list to be ordered by presumed truncations SHOULD permit this list to be ordered by presumed
strength and SHOULD allow different truncations for the same strength and SHOULD allow different truncations for the same
algorithm to be treated as separate entities in this list. When so algorithm to be treated as separate entities in this list. When so
implemented, policies SHOULD accept a presumed stronger algorithm and implemented, policies SHOULD accept a presumed stronger algorithm and
truncation than the minimum strength required by the policy. truncation than the minimum strength required by the policy.
If a TSIG is received with truncation which is permitted under If a TSIG is received with truncation that is permitted under
Section 3 above but the MAC is too short for the local policy in Section 3 above but the MAC is too short for the local policy in
force, an RCODE of TBA [22 suggested](BADTRUNC) MUST be returned. force, an RCODE of 22 (BADTRUNC) MUST be returned.
INTERNET-DRAFT HMAC-SHA TSIG Identifiers
5. IANA Considerations 5. IANA Considerations
This document, on approval for publication as a standards track RFC, This document (1) registers the new TSIG algorithm identifiers listed
(1) registers the new TSIG algorithm identifiers listed in Section 2 in Section 2 with IANA and (2) allocates the BADTRUNC RCODE 22 in
with IANA and (2) allocates the BADTRUNC RCODE TBA [22 suggested] in Section 4 [RFC2845].
Section 4. [RFC 2845]
6. Security Considerations 6. Security Considerations
For all of the message authentication code algorithms listed herein, For all of the message authentication code algorithms listed herein,
those producing longer values are believed to be stronger; however, those producing longer values are believed to be stronger; however,
while there have been some arguments that mild truncation can while there have been some arguments that mild truncation can
strengthen a MAC by reducing the information available to an strengthen a MAC by reducing the information available to an
attacker, excessive truncation clearly weakens authentication by attacker, excessive truncation clearly weakens authentication by
reducing the number of bits an attacker has to try to break the reducing the number of bits an attacker has to try to break the
authentication by brute force [RFC 2104]. authentication by brute force [RFC 2104].
Significant progress has been made recently in cryptanalysis of hash Significant progress has been made recently in cryptanalysis of hash
function of the type used herein, all of which ultimately derive from function of the types used herein, all of which ultimately derive
the design of MD4. While the results so far should not effect HMAC, from the design of MD4. While the results so far should not effect
the stronger SHA-1 and SHA-256 algorithms are being made mandatory HMAC, the stronger SHA-1 and SHA-256 algorithms are being made
due to caution. mandatory due to caution.
See the Security Considerations section of [RFC 2845]. See also the See the Security Considerations section of [RFC 2845]. See also the
Security Considerations section of [RFC 2104] from which the limits Security Considerations section of [RFC2104] from which the limits on
on truncation in this RFC were taken. truncation in this RFC were taken.
7. Copyright and Disclaimer
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.
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.
INTERNET-DRAFT HMAC-SHA TSIG Identifiers
8. Normative References 7. Normative References
[FIPS 180-2] - "Secure Hash Standard", (SHA-1/224/256/384/512) US [FIPS180-2] "Secure Hash Standard", (SHA-1/224/256/384/512) US
Federal Information Processing Standard, with Change Notice 1, Federal Information Processing Standard, with Change
February 2004. Notice 1, February 2004.
[RFC 1321] - Rivest, R., "The MD5 Message-Digest Algorithm ", RFC [RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm ", RFC
1321, April 1992. 1321, April 1992.
[RFC 2104] - Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC:
Hashing for Message Authentication", RFC 2104, February 1997. Keyed-Hashing for Message Authentication", RFC 2104,
February 1997.
[RFC 2119] - Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC 2845] - Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B.
Wellington, "Secret Key Transaction Authentication for DNS (TSIG)", Wellington, "Secret Key Transaction Authentication for
RFC 2845, May 2000. DNS (TSIG)", RFC 2845, May 2000.
[RFC 3174] - Eastlake 3rd, D. and P. Jones, "US Secure Hash Algorithm [RFC3174] Eastlake 3rd, D. and P. Jones, "US Secure Hash Algorithm
1 (SHA1)", RFC 3174, September 2001. 1 (SHA1)", RFC 3174, September 2001.
[RFC 3874] - R. Housely, "A 224-bit One-way Hash Function: SHA-224", [RFC3874] Housley, R., "A 224-bit One-way Hash Function: SHA-224",
September 2004, RFC 3874, September 2004.
[SHA2draft] - Eastlake, D., T. Hansen, "US Secure Hash Algorithms [RFC4634] Eastlake, D. and T. Hansen, "US Secure Hash Algorithms
(SHA)", draft-eastlake-sha2-*.txt, work in progress. (SHA)", RFC 4634, July 2006.
[STD 13] [STD13] Mockapetris, P., "Domain names - concepts and
Mockapetris, P., "Domain names - concepts and facilities", STD facilities", STD 13, RFC 1034, November 1987.
13, RFC 1034, November 1987.
Mockapetris, P., "Domain names - implementation and Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
9. Informative References. 8. Informative References.
[RFC 2930] - Eastlake 3rd, D., "Secret Key Establishment for DNS
(TKEY RR)", RFC 2930, September 2000.
[RFC 2931] - Eastlake 3rd, D., "DNS Request and Transaction [RFC2930] Eastlake 3rd, D., "Secret Key Establishment for DNS (TKEY
Signatures ( SIG(0)s )", RFC 2931, September 2000. RR)", RFC 2930, September 2000.
[RFC 3645] - Kwan, S., Garg, P., Gilroy, J., Esibov, L., Westhead, [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures
J., and R. Hall, "Generic Security Service Algorithm for Secret Key ( SIG(0)s )", RFC 2931, September 2000.
Transaction Authentication for DNS (GSS-TSIG)", RFC 3645, October
2003.
INTERNET-DRAFT HMAC-SHA TSIG Identifiers [RFC3645] Kwan, S., Garg, P., Gilroy, J., Esibov, L., Westhead, J.,
and R. Hall, "Generic Security Service Algorithm for
Secret Key Transaction Authentication for DNS (GSS-
TSIG)", RFC 3645, October 2003.
Author's Address Author's Address
Donald E. Eastlake 3rd Donald E. Eastlake 3rd
Motorola Laboratories Motorola Laboratories
155 Beaver Street 155 Beaver Street
Milford, MA 01757 USA Milford, MA 01757 USA
Telephone: +1-508-786-7554 (w) Phone: +1-508-786-7554 (w)
EMail: Donald.Eastlake@motorola.com EMail: Donald.Eastlake@motorola.com
Additional IPR Provisions Full 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.
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.
Intellectual Property
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Intellectual Property Rights or other rights that might be claimed Intellectual Property Rights or other rights that might be claimed to
to pertain to the implementation or use of the technology pertain to the implementation or use of the technology described in
described in this document or the extent to which any license this document or the extent to which any license under such rights
under such rights might or might not be available; nor does it might or might not be available; nor does it represent that it has
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rights in RFC documents can be found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
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attempt made to obtain a general license or permission for the use attempt made to obtain a general license or permission for the use of
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The IETF invites any interested party to bring to its attention
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proprietary rights that may cover technology that may be required
to implement this standard. Please address the information to the
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Expiration and File Name The IETF invites any interested party to bring to its attention any
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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.
This draft expires in July 2006. Acknowledgement
Its file name is draft-ietf-dnsext-tsig-sha-06.txt Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
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