Yes, you can use CTR mode for AES-256: use the EVP interface with the EVP_CIPHER of EVP_aes_256_ctr().
However it is a fundamental requirement of CTR mode that the IV must be unique across messages. If you reuse the IV then your messages can be broken quite trivially. Therefore, if by a fixed IV, you mean that it is fixed across multiple messages then CTR mode is not suitable for you. Matt On 14 January 2013 19:25, Rohit Bansal <[email protected]> wrote: > Hi, > > Can somebody help me if CTR mode is supported in openssl for AES-256 > encryption? > > I dont want to use CBC and i have a fixed IV. > > Thanks, > Rohit >
