C# 中AES 加密和解密通用方法_c# aes

AES密码编写

​要编写AES算法，首先了解AES算法原理，AES算法是一个对称分组密码算法。数据分组长度必须是 128 bits，使用的密钥长度为 128，192 或 256 bits。对于三种不同密钥长度的 AES 算法，分别称为“AES-128”、“AES-192”、“AES-256”。AES加密算法涉及4种操作：字节替代（SubBytes）、行移位（ShiftRows）、列混（MixColumns）和轮密钥加（AddRoundKey）。

​ 从AES的加密和解密的流程图中可知：解密算法的每一步分别对应加密算法的逆操作。加解密所有操作的顺序正好是相反的，正是这样才保证了算法的正确性。加解密中每轮的密钥分别由种子密钥经过密钥扩展算法得到，算法中16字节的明文、密文和轮子密钥都以一个4x4的矩阵表示。

下面提供一种C#方式实现的工具类：

  /// <summary>
    /// AES加解密字符串
    /// </summary>
    public static class AESCryptoTextProvider
    {
        #region 方法

        /// <summary>
        /// 加密
        /// IV等于Key且Key和IV将被转换为MD5值
        /// </summary>
        /// <param name="key">密钥</param>
        /// <param name="sourceText">原文</param>
        /// <returns>密文(Base64字符串)</returns>
        public static string Encrypt(string key, string sourceText)
        {
            return Encrypt(key, key, sourceText);
        }

        /// <summary>
        /// 加密
        /// Key和IV将被转换为MD5值
        /// </summary>
        /// <param name="key">密钥</param>
        /// <param name="IV">初始化向量</param>
        /// <param name="sourceText">原文</param>
        /// <returns>密文(Base64字符串)</returns>
        public static string Encrypt(string key, string IV, string sourceText)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));
            if (IV == null)
                throw new ArgumentNullException(nameof(IV));
            if (sourceText == null)
                throw new ArgumentNullException(nameof(sourceText));

            using (SHA512 sha512 = SHA512.Create())
            {
                return Convert.ToBase64String(Encrypt(sha512.ComputeHash(System.Text.Encoding.UTF8.GetBytes(key)), sha512.ComputeHash(System.Text.Encoding.UTF8.GetBytes(IV)), sourceText));
            }
        }

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="rgbKey">密钥</param>
        /// <param name="rgbIV">初始化向量</param>
        /// <param name="sourceText">原文</param>
        /// <returns>密文</returns>
        public static byte[] Encrypt(byte[] rgbKey, byte[] rgbIV, string sourceText)
        {
            if (rgbKey == null)
                throw new ArgumentNullException(nameof(rgbKey));
            if (rgbIV == null)
                throw new ArgumentNullException(nameof(rgbIV));
            if (sourceText == null)
                throw new ArgumentNullException(nameof(sourceText));

            using (MemoryStream memoryStream = new MemoryStream())
            {
                using (Aes aes = Aes.Create())
                using (ICryptoTransform transform = aes.CreateEncryptor(rgbKey, rgbIV))
                using (CryptoStream cryptoStream = new CryptoStream(memoryStream, transform, CryptoStreamMode.Write))
                using (StreamWriter streamWriter = new StreamWriter(cryptoStream))
                {
                    streamWriter.Write(sourceText);
                    streamWriter.Flush();
                }

                return memoryStream.ToArray();
            }
        }

        /// <summary>
        /// 解密
        /// IV等于Key且Key和IV将被转换为MD5值
        /// </summary>
        /// <param name="key">密钥</param>
        /// <param name="cipherText">密文(Base64字符串)</param>
        /// <returns>原文</returns>
        public static string Decrypt(string key, string cipherText)
        {
            return Decrypt(key, key, cipherText);
        }

        /// <summary>
        /// 解密
        /// Key和IV将被转换为MD5值
        /// </summary>
        /// <param name="key">密钥</param>
        /// <param name="IV">初始化向量</param>
        /// <param name="cipherText">密文(Base64字符串)</param>
        /// <returns>原文</returns>
        public static string Decrypt(string key, string IV, string cipherText)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));
            if (IV == null)
                throw new ArgumentNullException(nameof(IV));
            if (cipherText == null)
                throw new ArgumentNullException(nameof(cipherText));

            using (SHA512 sha512 = SHA512.Create())
            {
                return Decrypt(sha512.ComputeHash(System.Text.Encoding.UTF8.GetBytes(key)), sha512.ComputeHash(System.Text.Encoding.UTF8.GetBytes(IV)), Convert.FromBase64String(cipherText));
            }
        }

        /// <summary>
        /// 解密
        /// IV等于Key
        /// </summary>
        /// <param name="key">密钥</param>
        /// <param name="cipherBuffer">密文</param>
        /// <returns>原文</returns>
        public static string Decrypt(string key, byte[] cipherBuffer)
        {
            return Decrypt(key, key, cipherBuffer);
        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="key">密钥</param>
        /// <param name="IV">初始化向量</param>
        /// <param name="cipherBuffer">密文</param>
        /// <returns>原文</returns>
        public static string Decrypt(string key, string IV, byte[] cipherBuffer)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));
            if (IV == null)
                throw new ArgumentNullException(nameof(IV));
            if (cipherBuffer == null)
                throw new ArgumentNullException(nameof(cipherBuffer));

            using (SHA512 sha512 = SHA512.Create())
            {
                return Decrypt(sha512.ComputeHash(System.Text.Encoding.UTF8.GetBytes(key)), sha512.ComputeHash(System.Text.Encoding.UTF8.GetBytes(IV)), cipherBuffer);
            }
        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="rgbKey">密钥</param>
        /// <param name="rgbIV">初始化向量</param>
        /// <param name="cipherBuffer">密文</param>
        /// <returns>原文</returns>
        public static string Decrypt(byte[] rgbKey, byte[] rgbIV, byte[] cipherBuffer)
        {
            if (rgbKey == null)
                throw new ArgumentNullException(nameof(rgbKey));
            if (rgbIV == null)
                throw new ArgumentNullException(nameof(rgbIV));
            if (cipherBuffer == null)
                throw new ArgumentNullException(nameof(cipherBuffer));

            using (MemoryStream stream = new MemoryStream(cipherBuffer))
            {
                return Decrypt(rgbKey, rgbIV, stream);
            }
        }

        /// <summary>
        /// 解密
        /// IV等于Key
        /// </summary>
        /// <param name="key">密钥</param>
        /// <param name="cipherStream">密文</param>
        /// <returns>原文</returns>
        public static string Decrypt(string key, Stream cipherStream)
        {
            return Decrypt(key, key, cipherStream);
        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="key">密钥</param>
        /// <param name="IV">初始化向量</param>
        /// <param name="cipherStream">密文</param>
        /// <returns>原文</returns>
        public static string Decrypt(string key, string IV, Stream cipherStream)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));
            if (IV == null)
                throw new ArgumentNullException(nameof(IV));
            if (cipherStream == null)
                throw new ArgumentNullException(nameof(cipherStream));

            using (SHA512 sha512 = SHA512.Create())
            {
                return Decrypt(sha512.ComputeHash(System.Text.Encoding.UTF8.GetBytes(key)), sha512.ComputeHash(System.Text.Encoding.UTF8.GetBytes(IV)), cipherStream);
            }
        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="rgbKey">密钥</param>
        /// <param name="rgbIV">初始化向量</param>
        /// <param name="cipherStream">密文</param>
        /// <returns>原文</returns>
        public static string Decrypt(byte[] rgbKey, byte[] rgbIV, Stream cipherStream)
        {
            if (rgbKey == null)
                throw new ArgumentNullException(nameof(rgbKey));
            if (rgbIV == null)
                throw new ArgumentNullException(nameof(rgbIV));
            if (cipherStream == null)
                throw new ArgumentNullException(nameof(cipherStream));

            using (Aes aes = Aes.Create())
            using (ICryptoTransform transform = aes.CreateDecryptor(rgbKey, rgbIV))
            using (CryptoStream cryptoStream = new CryptoStream(cipherStream, transform, CryptoStreamMode.Read))
            using (StreamReader streamReader = new StreamReader(cryptoStream))
            {
                return streamReader.ReadToEnd();
            }
        }

        #endregion
    }
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