1 files changed, 98 insertions, 0 deletions
diff --git a/plugins/VNLib.Plugins.Essentials.Accounts/src/SecurityProvider/RsaClientDataEncryption.cs b/plugins/VNLib.Plugins.Essentials.Accounts/src/SecurityProvider/RsaClientDataEncryption.cs
new file mode 100644
index 0000000..89aaf73
--- /dev/null
+++ b/plugins/VNLib.Plugins.Essentials.Accounts/src/SecurityProvider/RsaClientDataEncryption.cs
@@ -0,0 +1,98 @@
+/*
+* Copyright (c) 2024 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Plugins.Essentials.Accounts
+* File: RsaClientDataEncryption.cs 
+*
+* RsaClientDataEncryption.cs is part of VNLib.Plugins.Essentials.Accounts 
+* which is part of the larger VNLib collection of libraries and utilities.
+*
+* VNLib.Plugins.Essentials.Accounts 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.Accounts 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.Utils;
+using VNLib.Utils.Memory;
+
+namespace VNLib.Plugins.Essentials.Accounts.SecurityProvider
+{
+    internal static class RsaClientDataEncryption
+    {
+        /// <summary>
+        /// The client data encryption padding. Client library must match this padding
+        /// </summary>
+        public static readonly RSAEncryptionPadding ClientEncryptonPadding = RSAEncryptionPadding.OaepSHA256;
+
+        /// <summary>
+        /// Tries to encrypt the specified data using the specified public key
+        /// </summary>
+        /// <param name="base64PubKey">A base64 encoded public key used to encrypt client data</param>
+        /// <param name="data">Data to encrypt</param>
+        /// <param name="outputBuffer">The buffer to store encrypted data in</param>
+        /// <returns>
+        /// The number of encrypted bytes written to the output buffer,
+        /// or false (0) if the operation failed, or if no credential is 
+        /// specified.
+        /// </returns>
+        /// <exception cref="CryptographicException"></exception>
+        public static ERRNO TryEncrypt(ReadOnlySpan<char> base64PubKey, ReadOnlySpan<byte> data, Span<byte> outputBuffer)
+        {
+            if (base64PubKey.IsEmpty)
+            {
+                return ERRNO.E_FAIL;
+            }
+
+            //Alloc a buffer for decoding the public key
+            using UnsafeMemoryHandle<byte> pubKeyBuffer = MemoryUtil.UnsafeAllocNearestPage(base64PubKey.Length, true);
+
+            //Decode the public key
+            ERRNO pbkBytesWritten = VnEncoding.TryFromBase64Chars(base64PubKey, pubKeyBuffer.Span);
+
+            //Try to encrypt the data
+            return pbkBytesWritten ? TryEncrypt(pubKeyBuffer.Span[..(int)pbkBytesWritten], data, outputBuffer) : ERRNO.E_FAIL;
+        }
+
+        /// <summary>
+        /// Tries to encrypt the specified data using the specified public key
+        /// </summary>
+        /// <param name="rawPubKey">The raw SKI public key</param>
+        /// <param name="data">Data to encrypt</param>
+        /// <param name="outputBuffer">The buffer to store encrypted data in</param>
+        /// <returns>
+        /// The number of encrypted bytes written to the output buffer,
+        /// or false (0) if the operation failed, or if no credential is 
+        /// specified.
+        /// </returns>
+        /// <exception cref="CryptographicException"></exception>
+        public static ERRNO TryEncrypt(ReadOnlySpan<byte> rawPubKey, ReadOnlySpan<byte> data, Span<byte> outputBuffer)
+        {
+            if (rawPubKey.IsEmpty)
+            {
+                return false;
+            }
+
+            //Setup new empty rsa
+            using RSA rsa = RSA.Create();
+
+            //Import the public key
+            rsa.ImportSubjectPublicKeyInfo(rawPubKey, out _);
+
+            //Encrypt data with OaepSha256 as configured in the browser
+            return rsa.TryEncrypt(data, outputBuffer, ClientEncryptonPadding, out int bytesWritten) ? bytesWritten : ERRNO.E_FAIL;
+        }
+    }
+}