1 files changed, 133 insertions, 0 deletions
diff --git a/wrappers/dotnet/VNLib.Utils.Cryptography.Noscrypt/src/NoscryptSigner.cs b/wrappers/dotnet/VNLib.Utils.Cryptography.Noscrypt/src/NoscryptSigner.cs
new file mode 100644
index 0000000..c81790b
--- /dev/null
+++ b/wrappers/dotnet/VNLib.Utils.Cryptography.Noscrypt/src/NoscryptSigner.cs
@@ -0,0 +1,133 @@
+// Copyright (C) 2024 Vaughn Nugent
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+using System;
+using VNLib.Utils.Cryptography.Noscrypt.Random;
+using VNLib.Utils.Extensions;
+using VNLib.Utils.Memory;
+
+using static VNLib.Utils.Cryptography.Noscrypt.NoscryptLibrary;
+
+namespace VNLib.Utils.Cryptography.Noscrypt
+{
+    /// <summary>
+    /// A simple wrapper class to sign nostr message data using 
+    /// the noscrypt library
+    /// </summary>
+    /// <param name="noscrypt">The noscrypt library instance</param>
+    /// <param name="random">A random entropy pool used to source random data for signature entropy</param>
+    public class NoscryptSigner(INostrCrypto noscrypt, IRandomSource random)
+    {
+        /// <summary>
+        /// Gets the size of the buffer required to hold the signature
+        /// </summary>
+        public static int SignatureBufferSize => NC_SIGNATURE_SIZE;
+
+        /// <summary>
+        /// Signs a message using the specified private key and message data
+        /// </summary>
+        /// <param name="hexPrivateKey">The hexadecimal private key used to sign the message</param>
+        /// <param name="message">The message data to sign</param>
+        /// <param name="format">A encoder used to convert the signature data to an encoded string</param>
+        /// <returns>The string encoded nostr signature</returns>
+        /// <exception cref="ArgumentException"></exception>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
+        public string SignData(string hexPrivateKey, ReadOnlySpan<byte> message, INostrSignatureEncoder? format = null)
+        {
+            ArgumentException.ThrowIfNullOrWhiteSpace(hexPrivateKey);
+            ArgumentOutOfRangeException.ThrowIfNotEqual(hexPrivateKey.Length / 2, NC_SEC_KEY_SIZE, nameof(hexPrivateKey));
+
+            //Have to allocate array unfortunately
+            byte[] privKey = Convert.FromHexString(hexPrivateKey);
+            try
+            {
+                return SignData(privKey.AsSpan(), message, format);
+            }
+            finally
+            {
+                //Always zero key beofre leaving
+                MemoryUtil.InitializeBlock(privKey);
+            }
+        }
+
+        /// <summary>
+        /// Signs a message using the specified secret key and message data
+        /// </summary>
+        /// <param name="secretKey">The secret key data buffer</param>
+        /// <param name="message">The message data to sign</param>
+        /// <param name="format">A encoder used to convert the signature data to an encoded string</param>
+        /// <returns>The string encoded nostr signature</returns>
+        /// <exception cref="ArgumentException"></exception>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
+        public string SignData(
+            ReadOnlySpan<byte> secretKey, 
+            ReadOnlySpan<byte> message, 
+            INostrSignatureEncoder? format = null
+        )
+        {
+            return SignData(in NCUtil.AsSecretKey(secretKey), message, format);
+        }
+
+        /// <summary>
+        /// Signs a message using the specified secret key and message data
+        /// </summary>
+        /// <param name="secretkey">A reference to the secret key structurer</param>
+        /// <param name="message">The message data to sign</param>
+        /// <param name="format">A encoder used to convert the signature data to an encoded string</param>
+        /// <returns>The string encoded nostr signature</returns>
+        /// <exception cref="ArgumentException"></exception>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
+        public string SignData(
+            ref readonly NCSecretKey secretkey, 
+            ReadOnlySpan<byte> message, 
+            INostrSignatureEncoder? format = null
+        )
+        {
+            //Default to hex encoding because that is the default NIP-01 format
+            format ??= HexSignatureEncoder.Instance;
+
+            Span<byte> sigBuffer = stackalloc byte[SignatureBufferSize];
+
+            SignData(message, sigBuffer);
+
+            return format.GetString(sigBuffer);
+        }
+
+
+        /// <summary>
+        /// Signs a message using the specified secret key and message data
+        /// </summary>
+        /// <param name="secretkey">A reference to the secret key structurer</param>
+        /// <param name="data">The message data to sign</param>
+        /// <param name="signature">A buffer to write signature data to</param>
+        /// <exception cref="ArgumentException"></exception>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
+        public void SignData(
+            ref readonly NCSecretKey secretkey, 
+            ReadOnlySpan<byte> data, 
+            Span<byte> signature
+        )
+        {
+            ArgumentOutOfRangeException.ThrowIfLessThan(signature.Length, NC_SIGNATURE_SIZE, nameof(signature));
+
+            //Signature generation required random entropy to be secure
+            Span<byte> entropy = stackalloc byte[NC_SIG_ENTROPY_SIZE];
+            random.GetRandomBytes(entropy);
+
+            noscrypt.SignData(in secretkey, entropy, data, signature);
+        }
+    }
+
+}