On 07/05/2019 20:47, Mirko J. Ploch wrote: > Thank you for your response. You answered my question. It is not available on my > target platform architecture (arm64). > > I do have a specific need for that cipher, and it does not have anything to do > with TLS. An app that I am working on requires it for JSON Web Encryption (JWE) > as the required encryption algorithm. > > https://tools.ietf.org/html/draft-ietf-jose-json-web-encryption-31#appendix-B Then (in spite of the name) this is not the cipher you want to use. This cipher can *only* do the AAD specified for TLS - it is not a general purpose cipher and so will not be capable of doing the AAD specified in that draft. You can probably achieve what you want using EVP_aes_128_cbc() and then using HMAC-SHA256 separately. Matt > > Best Regards, > Mirko > > On Tue, May 7, 2019 at 11:45 AM Matt Caswell <matt@xxxxxxxxxxx > <mailto:matt@xxxxxxxxxxx>> wrote: > > > > On 06/05/2019 16:41, Mirko J. Ploch wrote: > > Hello, > > > > I'm trying to use EVP_aes_128_cbc_hmac_sha256() for encryption on an iOS > device > > with arm64 architecture. I was able to get it working with the x86_64 > > architecture when running the iOS device simulator on an iMac. Is this > just not > > capable of working on an arm64 platform? > > > > Looking at the code for EVP_aes_128_cbc_hmac_sha256, it does not look like it. > > I'm hoping that there is a way to get it working. > > > https://github.com/openssl/openssl/blob/OpenSSL_1_1_1b/crypto/evp/e_aes_cbc_hmac_sha256.c > > This cipher is a special purpose cipher not intended for general use. It is > specifically targeted at usage in TLS. Unless you're writing a TLS stack you > probably don't want to use this. It is only available on some platforms and does > runtime detection to check whether the platform is suitable or not. Most > importantly the platform must have AES-NI support. > > It's usefulness even in a TLS stack is somewhat limited these days since it is > not relevant for TLSv1.3 and does not get used if encrypt-then-mac is negotiated > (which recent versions of OpenSSL will try to negotiate by default). > > Matt >
