is an optional set of flags. The library context <i>libctx</i> and the property query <i>propq</i> are used internally when retrieving algorithms from providers.</p>

<p>Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this function.</p>

<p>EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use because most clients will support it.</p>

<p>The algorithm passed in the <b>cipher</b> parameter must support ASN1 encoding of its parameters. If the cipher mode is GCM,