1 files changed, 81 insertions, 0 deletions

diff --git a/plugins/VNLib.Plugins.Essentials.SocialOauth/src/ClientRequestState.cs b/plugins/VNLib.Plugins.Essentials.SocialOauth/src/ClientRequestState.cs
new file mode 100644
index 0000000..2f35e48
--- /dev/null
+++ b/plugins/VNLib.Plugins.Essentials.SocialOauth/src/ClientRequestState.cs
@@ -0,0 +1,81 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Plugins.Essentials.SocialOauth
+* File: ClientRequestState.cs 
+*
+* ClientRequestState.cs is part of VNLib.Plugins.Essentials.SocialOauth which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Plugins.Essentials.SocialOauth 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.
+*
+* VNLib.Plugins.Essentials.SocialOauth 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.Security.Cryptography;
+
+using VNLib.Hashing;
+using VNLib.Utils;
+using VNLib.Utils.Memory;
+using VNLib.Utils.Memory.Caching;
+
+namespace VNLib.Plugins.Essentials.SocialOauth
+{
+    internal sealed class ClientRequestState : ICacheable
+    {
+        private readonly ReadOnlyMemory<byte> _rawKey;
+
+        /// <summary>
+        /// The raw nonce state bytes
+        /// </summary>
+        public ReadOnlyMemory<byte> State { get; private set; }
+
+        public ClientRequestState(ReadOnlySpan<char> keyChar, int nonceBytes)
+        {
+            //Get browser id 
+            _rawKey = Convert.FromHexString(keyChar);
+            RecomputeState(nonceBytes);
+        }
+
+        /// <summary>
+        /// Recomputes a nonce state and signature for the current 
+        /// connection
+        /// </summary>
+        /// <param name="nonceBytes">The size of the nonce (in bytes) to generate</param>
+        public void RecomputeState(int nonceBytes)
+        {
+            //Get random nonce buffer
+            State = RandomHash.GetRandomBytes(nonceBytes);
+        }
+        /// <summary>
+        /// Computes the signature of the supplied data based on the original
+        /// client state for this connection
+        /// </summary>
+        /// <param name="data"></param>
+        /// <returns></returns>
+        public ERRNO ComputeSignatureForClient(ReadOnlySpan<byte> data, Span<byte> output)
+        {
+            return HMACSHA512.TryHashData(_rawKey.Span, data, output, out int count) ? count : ERRNO.E_FAIL;
+        }
+
+        public DateTime Expires { get; set; }
+        bool IEquatable<ICacheable>.Equals(ICacheable other) => ReferenceEquals(this, other);
+        void ICacheable.Evicted() 
+        {
+            //Zero secrets on eviction
+            Memory.UnsafeZeroMemory(State);
+            Memory.UnsafeZeroMemory(_rawKey);
+        }
+    }
+}
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