sig, err := SignASN1(rand, priv, hash)
	if err != nil {
		return nil, nil, err
	}

	r, s = new(big.Int), new(big.Int)
	var inner cryptobyte.String
	input := cryptobyte.String(sig)
	if !input.ReadASN1(&inner, asn1.SEQUENCE) ||
		!input.Empty() ||
		!inner.ReadASN1Integer(r) ||
		!inner.ReadASN1Integer(s) ||
		!inner.Empty() {
		return nil, nil, errors.New("invalid ASN.1 from SignASN1")
	}
	return r, s, nil
}