diff --git a/src/Renci.SshNet/Security/Cryptography/CipherDigitalSignature.cs b/src/Renci.SshNet/Security/Cryptography/CipherDigitalSignature.cs
index e61b5d655..0a83610d5 100644
--- a/src/Renci.SshNet/Security/Cryptography/CipherDigitalSignature.cs
+++ b/src/Renci.SshNet/Security/Cryptography/CipherDigitalSignature.cs
@@ -40,7 +40,11 @@ public override bool Verify(byte[] input, byte[] signature)
             var encryptedSignature = _cipher.Decrypt(signature);
             var hashData = Hash(input);
             var expected = DerEncode(hashData);
-            return expected.IsEqualTo(encryptedSignature);
+#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP2_1_OR_GREATER
+            return System.Security.Cryptography.CryptographicOperations.FixedTimeEquals(expected, encryptedSignature);
+#else
+            return Chaos.NaCl.CryptoBytes.ConstantTimeEquals(expected, encryptedSignature);
+#endif
         }
 
         /// <summary>
diff --git a/src/Renci.SshNet/Session.cs b/src/Renci.SshNet/Session.cs
index 3712ea768..6a2c81a43 100644
--- a/src/Renci.SshNet/Session.cs
+++ b/src/Renci.SshNet/Session.cs
@@ -1291,11 +1291,11 @@ private Message ReceiveMessage(Socket socket)
             if (_serverMac != null && _serverEtm)
             {
                 var clientHash = _serverMac.ComputeHash(data, 0, data.Length - serverMacLength);
-                var serverHash = data.Take(data.Length - serverMacLength, serverMacLength);
-
-                // TODO Add IsEqualTo overload that takes left+right index and number of bytes to compare.
-                // TODO That way we can eliminate the extra allocation of the Take above.
-                if (!serverHash.IsEqualTo(clientHash))
+#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP2_1_OR_GREATER
+                if (!CryptographicOperations.FixedTimeEquals(clientHash, new ReadOnlySpan<byte>(data, data.Length - serverMacLength, serverMacLength)))
+#else
+                if (!Security.Chaos.NaCl.CryptoBytes.ConstantTimeEquals(clientHash, 0, data, data.Length - serverMacLength, serverMacLength))
+#endif
                 {
                     throw new SshConnectionException("MAC error", DisconnectReason.MacError);
                 }
@@ -1319,11 +1319,11 @@ private Message ReceiveMessage(Socket socket)
             if (_serverMac != null && !_serverEtm)
             {
                 var clientHash = _serverMac.ComputeHash(data, 0, data.Length - serverMacLength);
-                var serverHash = data.Take(data.Length - serverMacLength, serverMacLength);
-
-                // TODO Add IsEqualTo overload that takes left+right index and number of bytes to compare.
-                // TODO That way we can eliminate the extra allocation of the Take above.
-                if (!serverHash.IsEqualTo(clientHash))
+#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP2_1_OR_GREATER
+                if (!CryptographicOperations.FixedTimeEquals(clientHash, new ReadOnlySpan<byte>(data, data.Length - serverMacLength, serverMacLength)))
+#else
+                if (!Security.Chaos.NaCl.CryptoBytes.ConstantTimeEquals(clientHash, 0, data, data.Length - serverMacLength, serverMacLength))
+#endif
                 {
                     throw new SshConnectionException("MAC error", DisconnectReason.MacError);
                 }