rename ZNP -> ZKP (zero-Knowledge proof)

thresholdkey.go

@@ -224,7 +224,7 @@ func (tpk *ThresholdSecretKey) computeHash(a, b, c4, ci2 *big.Int) *big.Int {
 	return new(big.Int).SetBytes(hash.Sum([]byte{}))
 }
 
-func (tpk *ThresholdSecretKey) DecryptAndProduceZNP(c *big.Int, random io.Reader) (*PartialDecryptionZKP, error) {
+func (tpk *ThresholdSecretKey) DecryptAndProduceZKP(c *big.Int, random io.Reader) (*PartialDecryptionZKP, error) {
 	pd := new(PartialDecryptionZKP)
 	pd.Key = tpk.getThresholdKey()
 	pd.C = c
@@ -264,7 +264,7 @@ func (tpk *ThresholdSecretKey) Validate(random io.Reader) error {
 	if err != nil {
 		return err
 	}
-	proof, err := tpk.DecryptAndProduceZNP(c.C, random)
+	proof, err := tpk.DecryptAndProduceZKP(c.C, random)
 	if err != nil {
 		return err
 	}