DerDecodeECDSASignature
extern KMF_RETURN DerDecodeECDSASignature(KMF_DATA *, KMF_DATA *);
ret = DerDecodeECDSASignature(&signed_data, &signature);
ret = DerDecodeECDSASignature(&signed_data, &signature);
rv = DerDecodeECDSASignature(&csrdata->signature.encrypted,