On Wed, Aug 30, 2017, Daniel Andrade wrote: > Hello, > > I have two buffers, one with a key and one with some data. The > objective is to calculate the AES-CMAC of the data with this key. I > managed to compute the AES-CMAC using type `EVP_aes_128_cbc()` with > the low-level interface: > > 1. CMAC_CTX *ctx = CMAC_CTX_new() > 2. CMAC_Init > 3. CMAC_Update > 4. CMAC_Final > 5. CMAC_CTX_free > > Can this be done with the high-level EVP interface? > > The EVP_DigestSign* set of functions expects a type EVP_MD, but > EVP_aes_128_cbc() is of type EVP_CIPHER. > Yes it is possible. One way is to create a new key using EVP_PKEY_new_mac_key() with type EVP_PKEY_CMAC. You pass that key to EVP_DigestSign*() with the digest set to NULL. You then have to set the cipher to use with the EVP_PKEY_CTRL_CIPHER ctrl (unfortunately there is currently no macro for this). Then calling EVP_DigestSignUpdate() and EVP_DigestSignaFinal() should work in the usual way and produce the correct CMAC. Steve. -- Dr Stephen N. Henson. OpenSSL project core developer. Commercial tech support now available see: http://www.openssl.org -- openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users
