feat(crypto): add ChaCha20 Encrypt and Decrypt functions

these work in all platforms except for webgl, where they will fail. A libsodium js library is needed
to get these to work for that platform.

Author: jasonboukheir

Algorand.Unity.Package/Packages/manifest.json

@@ -1,13 +1,13 @@
 {
   "dependencies": {
-    "com.unity.burst": "1.8.4",
-    "com.unity.ide.rider": "3.0.21",
+    "com.unity.burst": "1.8.7",
+    "com.unity.ide.rider": "3.0.24",
     "com.unity.ide.visualstudio": "2.0.18",
     "com.unity.ide.vscode": "1.2.5",
     "com.unity.mobile.android-logcat": "1.3.2",
     "com.unity.test-framework": "1.1.33",
     "com.unity.test-framework.performance": "3.0.0-pre.2",
-    "com.unity.testtools.codecoverage": "1.2.3",
+    "com.unity.testtools.codecoverage": "1.2.4",
     "com.unity.toolchain.macos-x86_64-linux-x86_64": "2.0.4",
     "com.unity.toolchain.win-x86_64-linux-x86_64": "2.0.4",
     "com.unity.ugui": "1.0.0",

Algorand.Unity.Package/Packages/packages-lock.json

@@ -18,7 +18,7 @@
       "url": "https://package.openupm.com"
     },
     "com.unity.burst": {
-      "version": "1.8.4",
+      "version": "1.8.7",
       "depth": 0,
       "source": "registry",
       "dependencies": {
@@ -45,7 +45,7 @@
       "url": "https://packages.unity.com"
     },
     "com.unity.ide.rider": {
-      "version": "3.0.21",
+      "version": "3.0.24",
       "depth": 0,
       "source": "registry",
       "dependencies": {
@@ -135,7 +135,7 @@
       "url": "https://packages.unity.com"
     },
     "com.unity.testtools.codecoverage": {
-      "version": "1.2.3",
+      "version": "1.2.4",
       "depth": 0,
       "source": "registry",
       "dependencies": {

Algorand.Unity.Package/ProjectSettings/ProjectVersion.txt

@@ -1,2 +1,2 @@
-m_EditorVersion: 2022.2.17f1
-m_EditorVersionWithRevision: 2022.2.17f1 (54cb9bda89c4)
+m_EditorVersion: 2022.3.4f1
+m_EditorVersionWithRevision: 2022.3.4f1 (35713cd46cd7)

Runtime/Algorand.Unity.Crypto/AssemblyInfo.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Algorand.Unity.Crypto.Tests")]

Runtime/Algorand.Unity.Crypto/AssemblyInfo.cs.meta

@@ -0,0 +1,40 @@
+using System;
+using System.Runtime.InteropServices;
+using Algorand.Unity.LowLevel;
+
+namespace Algorand.Unity.Crypto
+{
+    public static partial class ChaCha20Poly1305
+    {
+        [Serializable]
+        [StructLayout(LayoutKind.Explicit, Size = Size)]
+        public struct AuthTag : IByteArray, IEquatable<AuthTag>
+        {
+            public const int Size = 16;
+
+            [FieldOffset(0)]
+            internal unsafe fixed ulong buffer[Size / 8];
+
+            public int Length => Size;
+
+            public byte this[int index]
+            {
+                get => this.GetByteAt(index);
+                set => this.SetByteAt(index, value);
+            }
+
+            public unsafe void* GetUnsafePtr()
+            {
+                fixed (ulong* b = buffer)
+                {
+                    return b;
+                }
+            }
+
+            public bool Equals(AuthTag other)
+            {
+                return ByteArray.Equals(this, other);
+            }
+        }
+    }
+}

Runtime/Algorand.Unity.Crypto/ChaCha20Poly1305.meta

@@ -0,0 +1,39 @@
+using Algorand.Unity.LowLevel;
+using Unity.Collections;
+using Unity.Collections.LowLevel.Unsafe;
+
+namespace Algorand.Unity.Crypto
+{
+    public static partial class ChaCha20Poly1305
+    {
+        public enum DecryptionError
+        {
+            None = 0,
+            VerificationFailed = -1
+        }
+
+        public static unsafe DecryptionError Decrypt<TCipher>(
+            NativeList<byte> message,
+            TCipher cipher,
+            Key key,
+            Nonce nonce
+        )
+            where TCipher : struct, IByteArray
+        {
+            message.Length = cipher.Length - AuthTag.Size;
+            var errorCode = sodium.crypto_aead_chacha20poly1305_ietf_decrypt(
+                message.GetUnsafePtr(),
+                out var messageLength,
+                null,
+                cipher.GetUnsafePtr(),
+                (ulong)cipher.Length,
+                null,
+                0,
+                nonce.GetUnsafePtr(),
+                key.GetUnsafePtr()
+            );
+            message.Length = (int)messageLength;
+            return (DecryptionError)errorCode;
+        }
+    }
+}