return false
	}
	x.Mod(x, N)
	return x.Cmp(r) == 0
}

var one = new(big.Int).SetInt64(1)

// randFieldElement returns a random element of the order of the given
// curve using the procedure given in FIPS 186-4, Appendix B.5.2.
func randFieldElement(c elliptic.Curve, rand io.Reader) (k *big.Int, err error) {
	// See randomPoint for notes on the algorithm. This has to match, or s390x

	c := priv.Curve
	functionCode, blockSize, ok := canUseKDSA(c)
	if !ok {
		return nil, errNoAsm
	}
	for {
		var k *big.Int
		k, err = randFieldElement(c, csprng)
		if err != nil {
			return nil, err
		}

		// The parameter block looks like the following for sign.
		// 	+---------------------+
		// 	|   Signature(R)      |
		//	+---------------------+