Decodes a DER encoded ECDSA signature (note: this function changes* pp
(*pp += len)).
\param sig pointer to ECDSA_SIG pointer (may be NULL)
\param pp memory buffer with the DER encoded signature
\param len length of the buffer
\return pointer to the decoded ECDSA_SIG structure (or NULL)
Decodes a DER encoded ECDSA signature (note: this function changes* pp (*pp += len)). \param sig pointer to ECDSA_SIG pointer (may be NULL) \param pp memory buffer with the DER encoded signature \param len length of the buffer \return pointer to the decoded ECDSA_SIG structure (or NULL)