diff --git a/ecdh.go b/ecdh.go
index 666e6c7..5d79db6 100644
--- a/ecdh.go
+++ b/ecdh.go
@@ -20,9 +20,8 @@ func (k *PublicKeyECDH) finalize() {
 }
 
 type PrivateKeyECDH struct {
-	_pkey        C.GO_EVP_PKEY_PTR
-	curve        string
-	hasPublicKey bool
+	_pkey C.GO_EVP_PKEY_PTR
+	curve string
 }
 
 func (k *PrivateKeyECDH) finalize() {
@@ -52,20 +51,13 @@ func NewPrivateKeyECDH(curve string, bytes []byte) (*PrivateKeyECDH, error) {
 	if err != nil {
 		return nil, err
 	}
-	k := &PrivateKeyECDH{pkey, curve, false}
+	k := &PrivateKeyECDH{pkey, curve}
 	runtime.SetFinalizer(k, (*PrivateKeyECDH).finalize)
 	return k, nil
 }
 
 func (k *PrivateKeyECDH) PublicKey() (*PublicKeyECDH, error) {
 	defer runtime.KeepAlive(k)
-	if !k.hasPublicKey {
-		err := deriveEcdhPublicKey(k._pkey, k.curve)
-		if err != nil {
-			return nil, err
-		}
-		k.hasPublicKey = true
-	}
 	var pkey C.GO_EVP_PKEY_PTR
 	defer func() {
 		C.go_openssl_EVP_PKEY_free(pkey)
@@ -141,6 +133,7 @@ func newECDHPkey1(nid C.int, bytes []byte, isPrivate bool) (pkey C.GO_EVP_PKEY_P
 			C.go_openssl_EC_KEY_free(key)
 		}
 	}()
+	group := C.go_openssl_EC_KEY_get0_group(key)
 	if isPrivate {
 		priv := C.go_openssl_BN_bin2bn(base(bytes), C.int(len(bytes)), nil)
 		if priv == nil {
@@ -150,8 +143,15 @@ func newECDHPkey1(nid C.int, bytes []byte, isPrivate bool) (pkey C.GO_EVP_PKEY_P
 		if C.go_openssl_EC_KEY_set_private_key(key, priv) != 1 {
 			return nil, newOpenSSLError("EC_KEY_set_private_key")
 		}
+		pub, err := pointMult(group, priv)
+		if err != nil {
+			return nil, err
+		}
+		defer C.go_openssl_EC_POINT_free(pub)
+		if C.go_openssl_EC_KEY_set_public_key(key, pub) != 1 {
+			return nil, newOpenSSLError("EC_KEY_set_public_key")
+		}
 	} else {
-		group := C.go_openssl_EC_KEY_get0_group(key)
 		pub := C.go_openssl_EC_POINT_new(group)
 		if pub == nil {
 			return nil, newOpenSSLError("EC_POINT_new")
@@ -196,39 +196,25 @@ func newECDHPkey3(nid C.int, bytes []byte, isPrivate bool) (C.GO_EVP_PKEY_PTR, e
 	return newEvpFromParams(C.GO_EVP_PKEY_EC, selection, params)
 }
 
+func pointMult(group C.GO_EC_GROUP_PTR, priv C.GO_BIGNUM_PTR) (C.GO_EC_POINT_PTR, error) {
+	// OpenSSL does not expose any method to generate the public
+	// key from the private key [1], so we have to calculate it here.
+	// [1] https://github.com/openssl/openssl/issues/18437#issuecomment-1144717206
+	pt := C.go_openssl_EC_POINT_new(group)
+	if pt == nil {
+		return nil, newOpenSSLError("EC_POINT_new")
+	}
+	if C.go_openssl_EC_POINT_mul(group, pt, priv, nil, nil, nil) == 0 {
+		C.go_openssl_EC_POINT_free(pt)
+		return nil, newOpenSSLError("EC_POINT_mul")
+	}
+	return pt, nil
+}
+
 // deriveEcdhPublicKey sets the raw public key of pkey by deriving it from
 // the raw private key.
 func deriveEcdhPublicKey(pkey C.GO_EVP_PKEY_PTR, curve string) error {
-	derive := func(group C.GO_EC_GROUP_PTR, priv C.GO_BIGNUM_PTR) (C.GO_EC_POINT_PTR, error) {
-		// OpenSSL does not expose any method to generate the public
-		// key from the private key [1], so we have to calculate it here.
-		// [1] https://github.com/openssl/openssl/issues/18437#issuecomment-1144717206
-		pt := C.go_openssl_EC_POINT_new(group)
-		if pt == nil {
-			return nil, newOpenSSLError("EC_POINT_new")
-		}
-		if C.go_openssl_EC_POINT_mul(group, pt, priv, nil, nil, nil) == 0 {
-			C.go_openssl_EC_POINT_free(pt)
-			return nil, newOpenSSLError("EC_POINT_mul")
-		}
-		return pt, nil
-	}
 	switch vMajor {
-	case 1:
-		key := getECKey(pkey)
-		priv := C.go_openssl_EC_KEY_get0_private_key(key)
-		if priv == nil {
-			return newOpenSSLError("EC_KEY_get0_private_key")
-		}
-		group := C.go_openssl_EC_KEY_get0_group(key)
-		pub, err := derive(group, priv)
-		if err != nil {
-			return err
-		}
-		defer C.go_openssl_EC_POINT_free(pub)
-		if C.go_openssl_EC_KEY_set_public_key(key, pub) != 1 {
-			return newOpenSSLError("EC_KEY_set_public_key")
-		}
 	case 3:
 		var priv C.GO_BIGNUM_PTR
 		if C.go_openssl_EVP_PKEY_get_bn_param(pkey, _OSSL_PKEY_PARAM_PRIV_KEY, &priv) != 1 {
@@ -237,7 +223,7 @@ func deriveEcdhPublicKey(pkey C.GO_EVP_PKEY_PTR, curve string) error {
 		defer C.go_openssl_BN_clear_free(priv)
 		nid, _ := curveNID(curve)
 		pubBytes, err := generateAndEncodeEcPublicKey(nid, func(group C.GO_EC_GROUP_PTR) (C.GO_EC_POINT_PTR, error) {
-			return derive(group, priv)
+			return pointMult(group, priv)
 		})
 		if err != nil {
 			return err
@@ -313,7 +299,7 @@ func GenerateKeyECDH(curve string) (*PrivateKeyECDH, []byte, error) {
 	if err := bnToBinPad(priv, bytes); err != nil {
 		return nil, nil, err
 	}
-	k = &PrivateKeyECDH{pkey, curve, true}
+	k = &PrivateKeyECDH{pkey, curve}
 	runtime.SetFinalizer(k, (*PrivateKeyECDH).finalize)
 	return k, bytes, nil
 }