RFC 3711, "The Secure Real-time Transport Protocol (SRTP)", March 2004

Note: This RFC has been updated by RFC 5506, RFC 6904, RFC 9335

Errata ID: 7606
Status: Rejected
Type: Technical
Publication Format(s) : TEXT
Reported By: David Satterlee
Date Reported: 2023-08-17
Rejected by: Francesca Palombini
Date Rejected: 2023-11-07

Section B.3 says:

   This section provides test data for the default key derivation
   function, which uses AES-128 in Counter Mode.  In the following, we
   walk through the initial key derivation for the AES-128 Counter Mode
   cipher, which requires a 16 octet session encryption key and a 14
   octet session salt, and an authentication function which requires a
   94-octet session authentication key.

(...)

   Below, the auth key is shown on the left, while the corresponding AES
   input blocks are shown on the right.

   auth key                           AES input blocks
   CEBE321F6FF7716B6FD4AB49AF256A15   0EC675AD498AFEEAB6960B3AABE60000
   6D38BAA48F0A0ACF3C34E2359E6CDBCE   0EC675AD498AFEEAB6960B3AABE60001
   E049646C43D9327AD175578EF7227098   0EC675AD498AFEEAB6960B3AABE60002
   6371C10C9A369AC2F94A8C5FBCDDDC25   0EC675AD498AFEEAB6960B3AABE60003
   6D6E919A48B610EF17C2041E47403576   0EC675AD498AFEEAB6960B3AABE60004
   6B68642C59BBFC2F34DB60DBDFB2       0EC675AD498AFEEAB6960B3AABE60005

It should say:

   This section provides test data for the default key derivation
   function, which uses AES-128 in Counter Mode.  In the following, we
   walk through the initial key derivation for the AES-128 Counter Mode
   cipher, which requires a 16 octet session encryption key and a 14
   octet session salt, and an authentication function which requires a
   20-octet session authentication key.

(...)

   Below, the auth key is shown on the left, while the corresponding AES
   input blocks are shown on the right.

   auth key blocks                    AES input blocks
   CEBE321F6FF7716B6FD4AB49AF256A15   0EC675AD498AFEEAB6960B3AABE60000
   6D38BAA4                           0EC675AD498AFEEAB6960B3AABE60001
 
   auth key: CEBE321F6FF7716B6FD4AB49AF256A156D38BAA4

Notes:

The RFC specifies a 160 bit, 20-octet session authentication key throughout (section 5.2, Section 8.2, Section 9.2 and Section 9.5), but the vectors and derivation in section B.3 specifies the need for a 94-octet session key, and includes test vectors as such.
--VERIFIER NOTES--
This test vector does not contradict any other section. It explicitly says that it is a test vector for "an authentication function which requires a 94-octet session authentication key".

In rejecting this Errata report I note that the reported text is not an error, but a deliberate decision of the authors and working group.

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