articular a return value of -2 indicates the operation is not supported by the public key algorithm.</p>

<h1 id="EXAMPLES">EXAMPLES</h1>

<p>Verify signature using PKCS#1 and SHA256 digest:</p>

<pre><code>#include &lt;openssl/evp.h&gt;
#include &lt;openssl/rsa.h&gt;

EVP_PKEY_CTX *ctx;
unsigned char *md, *sig;
size_t mdlen, siglen;
EVP_PKEY *verify_key;

/*
 * NB: assumes verify_key, sig, siglen md and mdlen are already set up
 * and that verify_key is an RSA public key
 */
ctx = EVP_PKEY_CTX_new(verify_k