d by the public key algorithm.</p>

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

<p>Recover digest originally signed 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 *rout, *sig;
 size_t routlen, siglen;
 EVP_PKEY *verify_key;

 /*
  * NB: assumes verify_key, sig and siglen are already set up
  * and that verify_key is an RSA public key
  */
 ctx = EVP_PKEY_CTX_new(verify_key, NULL /* no engine */);
 if (!ctx)
     /* Err