diff --git a/handshake_client_tls13.go b/handshake_client_tls13.go
index 12ff3a4..3bdd937 100644
--- a/handshake_client_tls13.go
+++ b/handshake_client_tls13.go
@@ -353,7 +353,7 @@ func (hs *clientHandshakeStateTLS13) establishHandshakeKeys() error {
 		c.sendAlert(alertIllegalParameter)
 		return errors.New("tls: invalid server key share")
 	}
-	sharedKey, err := hs.ecdheKey.Curve().ECDH(hs.ecdheKey, peerKey)
+	sharedKey, err := hs.ecdheKey.ECDH(peerKey)
 	if err != nil {
 		c.sendAlert(alertIllegalParameter)
 		return errors.New("tls: invalid server key share")
diff --git a/handshake_server_tls13.go b/handshake_server_tls13.go
index 9b7356a..80d4dce 100644
--- a/handshake_server_tls13.go
+++ b/handshake_server_tls13.go
@@ -220,7 +220,7 @@ GroupSelection:
 		c.sendAlert(alertIllegalParameter)
 		return errors.New("tls: invalid client key share")
 	}
-	hs.sharedKey, err = key.Curve().ECDH(key, peerKey)
+	hs.sharedKey, err = key.ECDH(peerKey)
 	if err != nil {
 		c.sendAlert(alertIllegalParameter)
 		return errors.New("tls: invalid client key share")
diff --git a/key_agreement.go b/key_agreement.go
index 027060d..2c8c5b8 100644
--- a/key_agreement.go
+++ b/key_agreement.go
@@ -264,7 +264,7 @@ func (ka *ecdheKeyAgreement) processClientKeyExchange(config *Config, cert *Cert
 	if err != nil {
 		return nil, errClientKeyExchange
 	}
-	preMasterSecret, err := ka.key.Curve().ECDH(ka.key, peerKey)
+	preMasterSecret, err := ka.key.ECDH(peerKey)
 	if err != nil {
 		return nil, errClientKeyExchange
 	}
@@ -307,7 +307,7 @@ func (ka *ecdheKeyAgreement) processServerKeyExchange(config *Config, clientHell
 	if err != nil {
 		return errServerKeyExchange
 	}
-	ka.preMasterSecret, err = key.Curve().ECDH(key, peerKey)
+	ka.preMasterSecret, err = key.ECDH(peerKey)
 	if err != nil {
 		return errServerKeyExchange
 	}