maximum length of a DER encoded ECDSA signature created with the private EC key <i>eckey</i>. To obtain the actual signature size use <a href="../man3/EVP_PKEY_sign.html">EVP_PKEY_sign(3)</a> with a NULL <i>sig</i> parameter.</p>

<p>ECDSA_sign() computes a digital signature of the <i>dgstlen</i> bytes hash value <i>dgst</i> using the private EC key <i>eckey</i>. The DER encoded signatures is stored in <i>sig</i> and its length is returned in <i>sig_len</i>. Note: <i>sig</i> must point to ECDSA_size(eckey) 