Search code examples
sslopensslmutual-authentication

How to implement mutual authentication for client in Openssl?

What function calls do I need to do for mutual authentication ? I have searched a lot, but didn't find anything useful.

Can anybody help me doing this ?

Solution

  • The function calls you are looking for are the SSL_set_verify() family. On the server side, specifying SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT requires a valid client certificate. On the client side, just SSL_VERIFY_PEER is needed.

    Both sides must also ensure that anonymous ciphers are not allowed in their specified cipher list (set with SL_CTX_set_cipher_list()).