1 files changed, 171 insertions, 0 deletions
diff --git a/wrappers/dotnet/VNLib.Utils.Cryptography.Noscrypt/src/Encryption/NCCipherUtil.cs b/wrappers/dotnet/VNLib.Utils.Cryptography.Noscrypt/src/Encryption/NCCipherUtil.cs
new file mode 100644
index 0000000..5dc2a94
--- /dev/null
+++ b/wrappers/dotnet/VNLib.Utils.Cryptography.Noscrypt/src/Encryption/NCCipherUtil.cs
@@ -0,0 +1,171 @@
+// 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 System.Diagnostics;
+using System.Runtime.InteropServices;
+
+using VNLib.Utils.Cryptography.Noscrypt.@internal;
+
+using static VNLib.Utils.Cryptography.Noscrypt.NoscryptLibrary;
+
+using NCResult = System.Int64;
+
+namespace VNLib.Utils.Cryptography.Noscrypt.Encryption
+{
+    public unsafe static class NCCipherUtil
+    {
+        /*
+         * This class wraps the low-level cipher functions provided by 
+         * the Noscrypt utility side-car library. 
+         */
+
+        internal static nint Alloc(NCContext ctx, uint version, uint flags)
+        {
+            nint cipher = GetTable(ctx).NCUtilCipherAlloc(version, flags);
+
+            if (cipher == nint.Zero)
+            {
+                throw new OutOfMemoryException("Failed to allocate cipher context");
+            }
+
+            //Ensure flags are identical to those set during allocation
+            Debug.Assert(GetFlags(ctx, cipher) == flags);
+
+            return cipher;
+        }
+
+        internal static uint GetFlags(NCContext ctx, nint cipher)
+        {
+            NCResult result = GetTable(ctx).NCUtilCipherGetFlags(cipher);
+
+            NCUtil.CheckResult<FunctionTable.NCUtilCipherGetFlagsDelegate>(result, raiseOnFailure: true);
+
+            return (uint)result;
+        }
+
+        internal static void Free(NCContext ctx, nint cipher) => GetTable(ctx).NCUtilCipherFree(cipher);
+
+        internal static int GetIvSize(NCContext ctx, nint cipher)
+        {
+            NCResult result = GetTable(ctx).NCUtilCipherGetIvSize(cipher);
+
+            NCUtil.CheckResult<FunctionTable.NCUtilCipherGetIvSizeDelegate>(result, raiseOnFailure: true);
+
+            return checked((int)result);
+        }
+
+        internal static void SetProperty(NCContext ctx, nint cipher, uint property, ref readonly byte value, uint valueLen)
+        {
+            fixed (byte* valPtr = &value)
+            {
+                NCResult result = GetTable(ctx).NCUtilCipherSetProperty(cipher, property, valPtr, valueLen);
+
+                NCUtil.CheckResult<FunctionTable.NCUtilCipherSetPropertyDelegate>(result, raiseOnFailure: true);
+            }
+        }
+
+        internal static uint GetOutputSize(NCContext ctx, nint cipher)
+        {
+            NCResult result = GetTable(ctx).NCUtilCipherGetOutputSize(cipher);
+
+            NCUtil.CheckResult<FunctionTable.NCUtilCipherGetOutputSizeDelegate>(result, raiseOnFailure: true);
+
+            return (uint)result;
+        }
+
+        internal static uint ReadOutput(NCContext ctx, nint cipher, ref byte outputData, uint outLen)
+        {
+            fixed (byte* outPtr = &outputData)
+            {
+                NCResult result = GetTable(ctx).NCUtilCipherReadOutput(cipher, outPtr, outLen);
+
+                NCUtil.CheckResult<FunctionTable.NCUtilCipherReadOutputDelegate>(result, raiseOnFailure: true);
+
+                return (uint)result;
+            }
+        }
+
+        internal static void InitCipher(NCContext ctx, nint cipher, byte* inputPtr, uint inputSize)
+        {
+            NCResult result = GetTable(ctx).NCUtilCipherInit(cipher, inputPtr, inputSize);
+
+            NCUtil.CheckResult<FunctionTable.NCUtilCipherInitDelegate>(result, raiseOnFailure: true);
+        }
+
+        internal static void Update(
+            NCContext ctx,
+            nint cipher,
+            ref readonly NCSecretKey localKey,
+            ref readonly NCPublicKey remoteKey
+        )
+        {
+            fixed (NCSecretKey* sk = &localKey)
+            fixed (NCPublicKey* pk = &remoteKey)
+            {
+                NCResult result = GetTable(ctx).NCUtilCipherUpdate(
+                    cipher: cipher,
+                    libContext: ctx.DangerousGetHandle(),
+                    secKey: sk,
+                    pubKey: pk
+                );
+
+                NCUtil.CheckResult<FunctionTable.NCUtilCipherInitDelegate>(result, raiseOnFailure: true);
+            }
+        }
+
+
+#if DEBUG
+        /*
+         * Conversation key is not meant to be a public api. Callers 
+         * should use Encrypt/Decrypt methods to handle encryption.
+         * 
+         * This method exists for vector testing purposes only.
+         */
+        public static void GetConverstationKey(
+            NCContext ctx,
+            ref readonly NCSecretKey localKey,
+            ref readonly NCPublicKey remoteKey,
+            Span<byte> conversationKeyOut32
+        )
+        {
+            ArgumentNullException.ThrowIfNull(ctx);
+            ArgumentOutOfRangeException.ThrowIfNotEqual(
+                conversationKeyOut32.Length, 
+                NC_CONVERSATION_KEY_SIZE, 
+                nameof(conversationKeyOut32)
+            );
+
+            fixed (NCSecretKey* sk = &localKey)
+            fixed (NCPublicKey* pk = &remoteKey)
+            fixed(byte* convKey32Ptr = &MemoryMarshal.GetReference(conversationKeyOut32))
+            {
+                NCResult result = GetTable(ctx).NCGetConversationKey(
+                    ctx: ctx.DangerousGetHandle(),
+                    sk,
+                    pk,
+                    convKey32Ptr
+                );
+
+                NCUtil.CheckResult<FunctionTable.NCUtilCipherInitDelegate>(result, raiseOnFailure: true);
+            }
+        }
+#endif
+
+        private static ref readonly FunctionTable GetTable(NCContext ctx) 
+            => ref ctx.Library.Functions;
+    }
+
+}