On Wednesday, August 21, 2013 5:55:48 AM UTC-4, Gregor Pintar wrote: > > On Wednesday, August 21, 2013 2:24:52 AM UTC+2, Jeffrey Walton wrote: > >> On Monday, August 19, 2013 1:50:54 PM UTC-4, Gregor Pintar wrote: >>> >>> I'm little confused. >>> >>> Is constant for 256-bit block size in CMAC: >>> http://www.cryptopp.com/docs/ref/cmac_8cpp_source.html really correct? >>> >> Yes, it appears correct. >> >> Crypto++ self tests include RFC 4493 vectors. See >> http://sourceforge.net/p/cryptopp/code/541/tree/trunk/c5/TestVectors/cmac.txt >> . >> >> Running NIST test vectors from SP 800-38B (Example 9 - 12) were also OK. >> >> > What problems are you experiencing? >> > > Tests cover only 64-bit and 128-bit block sizes. > > Non-leading coefficients of polynomial 256, 10, 5, 2 (which is defined in > > http://csrc.nist.gov/groups/ST/toolkit/BCM/documents/proposedmodes/omac/omac-spec.pdf > ) > is 0x425 and not 0x423. > Ah, OK.... For documentation, cmac.h file points to the Cyptolounge. Cryptolounge points to NIST SP 800-38D. SP 800-38D only provides a specification for 64-bit and 128-bit block ciphers (and RFC 4493 only provides for 128-bit blocks).
The Cryptolounge page also references omac.html. Its available on the Wayback machine at http://web.archive.org/web/20090818223220/http://www.nuee.nagoya-u.ac.jp/labs/tiwata/omac/omac.html. OMAC can be either OMAC1 or OMAC2. Its not clear to me which is being used by Crypto++. Some of the links on that Wayback page are dead, so I can't find something that specifies the subkey (either 0x423 or 0x425). If both OMAC1 and OMAC2 callout 0x425, I would probably say its a bug in the source code. Jeff -- -- You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to [email protected]. More information about Crypto++ and this group is available at http://www.cryptopp.com. --- You received this message because you are subscribed to the Google Groups "Crypto++ Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
