diff --git a/crypto/goolm/crypto/curve25519.go b/crypto/goolm/crypto/curve25519.go
index e9759501..6e42d886 100644
--- a/crypto/goolm/crypto/curve25519.go
+++ b/crypto/goolm/crypto/curve25519.go
@@ -53,6 +53,7 @@ func (c Curve25519KeyPair) B64Encoded() id.Curve25519 {
 
 // SharedSecret returns the shared secret between the key pair and the given public key.
 func (c Curve25519KeyPair) SharedSecret(pubKey Curve25519PublicKey) ([]byte, error) {
+	// Note: the standard library checks that the output is non-zero
 	return c.PrivateKey.SharedSecret(pubKey)
 }
 
diff --git a/crypto/goolm/crypto/curve25519_test.go b/crypto/goolm/crypto/curve25519_test.go
index 9039c126..2550f15e 100644
--- a/crypto/goolm/crypto/curve25519_test.go
+++ b/crypto/goolm/crypto/curve25519_test.go
@@ -25,6 +25,8 @@ func TestCurve25519(t *testing.T) {
 	fromPrivate, err := crypto.Curve25519GenerateFromPrivate(firstKeypair.PrivateKey)
 	assert.NoError(t, err)
 	assert.Equal(t, fromPrivate, firstKeypair)
+	_, err = secondKeypair.SharedSecret(make([]byte, crypto.Curve25519PublicKeyLength))
+	assert.Error(t, err)
 }
 
 func TestCurve25519Case1(t *testing.T) {