On Dec 6, 2003, at 3:26, Jeremiah Rogers wrote:


I'm having trouble pinpointing the origin of the initial hash values for SHA 224 and, for that matter, 128. These values are defined as hex representations of cube roots of primes for sha-1 of lengths 256, 384 and 512, but I can't find where they were obtained for the shorter lengths.

Thanks and apologies if this is something well known.

I'd like to second this request for clarification.


I noted that 224 yields a security level identical to 2-key Triple DES.

A quick Google search reveals that SHA-224 is mentioned a few times, in
  draft-ietf-pkix-rsa-pkalgs-01.txt
  draft-ietf-smime-cms-rsa-kem-01.txt
among others.

A draft-ietf-pkix-sha224-00.txt is referenced but not yet available from the IETF website.



      *  80-bit security. The RSA key size SHOULD be at least 1024 bits,
         the hash function underlying KDF2 SHOULD be SHA-1 or above, and
         the symmetric key-wrapping scheme SHOULD be AES Key Wrap or
         Triple-DES Key Wrap.

      *  112-bit security. The RSA key size SHOULD be at least 2048
         bits, the hash function underlying KDF2 SHOULD be SHA-224 or
         above, and the symmetric key-wrapping scheme SHOULD be AES Key
         Wrap or Triple-DES Key Wrap.

      *  128-bit security. The RSA key size SHOULD be at least 3072
         bits, the hash function underlying KDF2 SHOULD be SHA-256 or
         above, and the symmetric key-wrapping scheme SHOULD be AES Key
         Wrap.

-- draft-ietf-smime-cms-rsa-kem-01.txt, pg4

-J

---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]

Reply via email to