feat(openai): 新增 AES 算法工具类

src/SKIT.FlurlHttpClient.Wechat.OpenAI/README.md

@@ -9,6 +9,7 @@
 ### 【功能特性】
 
 -   基于微信对话开放平台 API 封装。
+-   提供了微信对话开放平台所需的 AES、SHA-1 等算法工具类。
 -   提供了解析回调通知事件等扩展方法。
 
 ---

src/SKIT.FlurlHttpClient.Wechat.OpenAI/Utilities/AESUtility.cs

@@ -0,0 +1,105 @@
+using System;
+using System.Security.Cryptography;
+
+namespace SKIT.FlurlHttpClient.Wechat.OpenAI.Utilities
+{
+    using SKIT.FlurlHttpClient.Primitives;
+
+    /// <summary>
+    /// AES 算法工具类。
+    /// </summary>
+    public static class AESUtility
+    {
+        /// <summary>
+        /// 基于 CBC 模式解密数据。
+        /// </summary>
+        /// <param name="keyBytes">AES 密钥字节数组。</param>
+        /// <param name="ivBytes">初始化向量字节数组。</param>
+        /// <param name="cipherBytes">待解密数据字节数组。</param>
+        /// <returns>解密后的数据字节数组。</returns>
+        public static byte[] DecryptWithCBC(byte[] keyBytes, byte[] ivBytes, byte[] cipherBytes)
+        {
+            if (keyBytes is null) throw new ArgumentNullException(nameof(keyBytes));
+            if (ivBytes is null) throw new ArgumentNullException(nameof(ivBytes));
+            if (cipherBytes is null) throw new ArgumentNullException(nameof(cipherBytes));
+
+            using (SymmetricAlgorithm aes = Aes.Create())
+            {
+                aes.Mode = CipherMode.CBC;
+                aes.Padding = PaddingMode.PKCS7;
+                aes.Key = keyBytes;
+                aes.IV = ivBytes;
+
+                using ICryptoTransform transform = aes.CreateDecryptor();
+                return transform.TransformFinalBlock(cipherBytes, 0, cipherBytes.Length);
+            }
+        }
+
+        /// <summary>
+        /// 基于 CBC 模式解密数据。
+        /// </summary>
+        /// <param name="encodingKey">经过编码后的（通常为 Base64）AES 密钥。</param>
+        /// <param name="encodingIV">经过编码后的（通常为 Base64）初始化向量。</param>
+        /// <param name="encodingCipher">经过编码后的（通常为 Base64）待解密数据。</param>
+        /// <returns>解密后的数据。</returns>
+        public static EncodedString DecryptWithCBC(EncodedString encodingKey, EncodedString encodingIV, EncodedString encodingCipher)
+        {
+            if (encodingKey.Value is null) throw new ArgumentNullException(nameof(encodingKey));
+            if (encodingIV.Value is null) throw new ArgumentNullException(nameof(encodingIV));
+            if (encodingCipher.Value is null) throw new ArgumentNullException(nameof(encodingCipher));
+
+            byte[] plainBytes = DecryptWithCBC(
+                keyBytes: EncodedString.FromString(encodingKey, fallbackEncodingKind: EncodingKinds.Base64),
+                ivBytes: EncodedString.FromString(encodingIV, fallbackEncodingKind: EncodingKinds.Base64),
+                cipherBytes: EncodedString.FromString(encodingCipher, fallbackEncodingKind: EncodingKinds.Base64)
+            );
+            return EncodedString.ToLiteralString(plainBytes);
+        }
+
+        /// <summary>
+        /// 基于 CBC 模式加密数据。
+        /// </summary>
+        /// <param name="keyBytes">AES 密钥字节数组。</param>
+        /// <param name="ivBytes">初始化向量字节数组。</param>
+        /// <param name="plainBytes">待加密数据字节数组。</param>
+        /// <returns>加密后的数据字节数组。</returns>
+        public static byte[] EncryptWithCBC(byte[] keyBytes, byte[] ivBytes, byte[] plainBytes)
+        {
+            if (keyBytes is null) throw new ArgumentNullException(nameof(keyBytes));
+            if (ivBytes is null) throw new ArgumentNullException(nameof(ivBytes));
+            if (plainBytes is null) throw new ArgumentNullException(nameof(plainBytes));
+
+            using (SymmetricAlgorithm aes = Aes.Create())
+            {
+                aes.Mode = CipherMode.CBC;
+                aes.Padding = PaddingMode.PKCS7;
+                aes.Key = keyBytes;
+                aes.IV = ivBytes;
+
+                using ICryptoTransform transform = aes.CreateEncryptor();
+                return transform.TransformFinalBlock(plainBytes, 0, plainBytes.Length);
+            }
+        }
+
+        /// <summary>
+        /// 基于 CBC 模式加密数据。
+        /// </summary>
+        /// <param name="encodingKey">经过编码后的（通常为 Base64）AES 密钥。</param>
+        /// <param name="encodingIV">经过编码后的（通常为 Base64）初始化向量。</param>
+        /// <param name="plainData">待加密数据。</param>
+        /// <returns>经过 Base64 编码的加密后的数据。</returns>
+        public static EncodedString EncryptWithCBC(EncodedString encodingKey, EncodedString encodingIV, string plainData)
+        {
+            if (encodingKey.Value is null) throw new ArgumentNullException(nameof(encodingKey));
+            if (encodingIV.Value is null) throw new ArgumentNullException(nameof(encodingIV));
+            if (plainData is null) throw new ArgumentNullException(nameof(plainData));
+
+            byte[] plainBytes = EncryptWithCBC(
+                keyBytes: EncodedString.FromString(encodingKey, fallbackEncodingKind: EncodingKinds.Base64),
+                ivBytes: EncodedString.FromString(encodingIV, fallbackEncodingKind: EncodingKinds.Base64),
+                plainBytes: EncodedString.FromLiteralString(plainData)
+            );
+            return EncodedString.ToBase64String(plainBytes);
+        }
+    }
+}