One more thing to correct myself. 2 as tag length is not allowed. only 4, 6, 8, 10, 12, 14, 16 are allowed.
On Wed, Jun 18, 2014 at 11:55 PM, Thulasi Goriparthi < thulasi.goripar...@gmail.com> wrote: > In the test program, you are feeding a fixed ccm_tag to decryption > process. This will not work for CCM, as tag length itself will also be an > input for tag generation. Change in tag length, will change the tag > produced. I modified the decryption api(aes_ccm_decrypt) to take the tag > generated by encryption api(aes_ccm_encrypt). It works fine. > > Note: Tag length will internally be embedded within the IV(nonce). > > > On Wed, Jun 18, 2014 at 8:12 PM, Michel <msa...@paybox.com> wrote: > >> I tried all of 2, 4, 6, 8, 10, 12, 14, 16 values, and always got a >> "Plaintext not available: tag verify failed". >> Even when tag length of decryption was equal to tag length of encryption. >> :-( >> It just works for : tag length of decryption = tag length of encryption = >> 16. >> >> Thanks again for your help. >> >> Le 18/06/2014 16:14, Thulasi Goriparthi a écrit : >> >> Truncate-able tags gave a way to truncated hmac extension. >>> Haven't gone through CCM RFC 3610 completely. >>> >>> I can see the restriction of possible M values(Tag lengths) to 2, 4, 6, >>> 8, 10, 12, 14, 16. Can you try reducing the tag size accordingly and see if >>> it succeeds. >>> >>> >> >> ______________________________________________________________________ >> OpenSSL Project http://www.openssl.org >> User Support Mailing List openssl-users@openssl.org >> Automated List Manager majord...@openssl.org >> > >
