On Wed, 2021-08-25 at 13:20 -0500, William Roberts wrote: > Hello, > > I am trying to verify an HMAC signature with the code below and the > EVP_DigestVerifyInit() > routine is failing with "error:0608F096:digital envelope > routines:EVP_PKEY_verify_init:operation not supported for this > keytype". Eventually it gets to EVP_PKEY_verify_init() and since the > ctx->pmeth->verify pointer is null, it sets this error. It's unclear > to me why this function pointer is NULL, can someone elaborate the > right way to do this via EVP interfaces? As HMAC is not a true signature algorithm there is no support for the EVP_DigestVerifyInit() operation with HMAC 'signatures'. You just have to use EVP_DigestSign*() operation to create a new HMAC and compare with the original value. -- Tomáš Mráz No matter how far down the wrong road you've gone, turn back. Turkish proverb [You'll know whether the road is wrong if you carefully listen to your conscience.]
