Re: omac using libtomcrypt

[Anil]

looks like i am getting correct results for message lengths 0 and 16 bytes.
But for messages of size greater than 16 bytes the output is not correct.

Thanks,
Anil

On Thursday, May 2, 2013 11:00:42 AM UTC+5:30, Anil wrote:

Hi,

I am using libtomcrypt library to find the message authentication code. The document says OMAC

can be used to calculate the MAC using block ciphers such as AES.  I am getting correct results

for CMAC using AES.  But i am not getting the correct output for mac using tdes algorithm.

I am using the following APIs from the library.

register_cipher(&des3_desc);

omac_memory(find_cipher("3des"), akey, auth_key_len, (pt+auth_off), auth_len, ct, (unsigned long*)&icv_len);

I am getting some output, but it is not matching the one given here.

Can i use omac_memory to find the CMAC for TDES algorithm ?

Thanks,

Anil 

[Anil]

Checked with the new version of libtomcrypt (v1.17). This issue is not there.

Thanks,
Anil