On 17/08/2022 06:30, Kreissl, Jochen wrote:
Hi,
given an SSL* or respectively an SSLCIPHER* struct, how can I figure out
the length of the IV used by the negotiated cipher of the handshake?
I noticed that EVP_CIPHER has a metod to query this information, but I
also don’t find a way to get an EVP_CIPHER from SSL*.
Any pointers (heh) would be very helpful, thanks.
Cheers
Given an SSL_CIPHER structure the associated EVP_CIPHER can be obtained
using something like this:
EVP_CIPHER *ciph =
EVP_get_cipherbyname(OBJ_nid2sn(SSL_CIPHER_get_cipher_nid(sslciph)))
But note that IV handling in TLS is a little complicated with the actual
IV that is used for an actual encryption/decryption operation being
composed of different elements. The details of which vary by ciphersuite
and protocol version.
Matt
