.net 中的AES加密解密

AES加密中向量長度是16個byte

密鑰長度有三種：16，24，32   單位byte

AES的區塊長度固定為128比特，密鑰長度則可以是128(6byte*8b)，192(24*8)或256(32*8)比特；

加密后的輸出要轉為base64 ，為什么呢？因為base64所有字符都是可打印，加密后的字符轉為base64才能被人看見，在復制時候不容易漏掉

 

在C#中AES加密解密寫法有：

 

using System.Security.Cryptography;
using System.Text.RegularExpressions;

 

　　　　 /// <summary>
        /// AES解密
        /// </summary>
        /// <param name="decryptString">AES密文</param>
        /// <param name="key">秘鑰（44個字符）</param>
        /// <param name="ivString">向量（16個字符）</param>
        /// <returns></returns>
        public static string AES_Decrypt(string decryptString, string key, string ivString)
        {
            try
            {

                key = key.PadRight(32, ' ');
                RijndaelManaged aes = new RijndaelManaged();

                byte[] iv = Encoding.UTF8.GetBytes(ivString.Substring(0,16));
                aes.Key = Encoding.UTF8.GetBytes(key.Substring(0, 32));
                aes.Mode = CipherMode.ECB;
                aes.IV = iv;
                aes.Padding = PaddingMode.PKCS7;  //
                

                ICryptoTransform rijndaelDecrypt = aes.CreateDecryptor();
                byte[] inputData = Convert.FromBase64String(decryptString);
                byte[] xBuff = rijndaelDecrypt.TransformFinalBlock(inputData, 0, inputData.Length);

                return Encoding.UTF8.GetString(xBuff);
            }
            catch (Exception ex)
            {
                throw;

            }
        }



        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="encriyptString">要被加密的字符串</param>
        /// <param name="key">秘鑰（44個字符）</param>
        /// <param name="ivString">向量長度（16個字符）</param>
        /// <returns></returns>
        public static string AES_Encrypt(string encriyptString, string key, string ivString)
        {
            key = key.PadRight(32, ' ');
            SymmetricAlgorithm aes = new RijndaelManaged();

            byte[] iv = Encoding.UTF8.GetBytes(ivString.Substring(0,16));
            

            aes.Key = Encoding.UTF8.GetBytes(key.Substring(0, 32));
            aes.Mode = CipherMode.ECB;
            aes.IV = iv;
            aes.Padding = PaddingMode.PKCS7; //
            

             ICryptoTransform rijndaelEncrypt = aes.CreateEncryptor();
            byte[] inputData = Encoding.UTF8.GetBytes(encriyptString);
            byte[] encryptedData = rijndaelEncrypt.TransformFinalBlock(inputData, 0, inputData.Length);
            
            return Convert.ToBase64String(encryptedData);
        }
        #endregion

    }

 填充（Padding）和運算模式(Mode)也可以自定義，不同的值有不同的結果

 

下面是另一種寫法

 /// <summary>
        /// AES加密算法
        /// </summary>
        /// <param name="plainText">明文字符串</param>
        /// <param name="strKey">密鑰</param>
        /// <returns>返回加密后的密文字節數組</returns>
        public static byte[] AESEncrypt(string plainText, string strKey)
        {
            //分組加密算法
            SymmetricAlgorithm des = Rijndael.Create();
            byte[] inputByteArray = Encoding.UTF8.GetBytes(plainText);//得到需要加密的字節數組
                                                                      //設置密鑰及密鑰向量
            des.Key = Encoding.UTF8.GetBytes(strKey);
            des.IV = _key1;
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            byte[] cipherBytes = ms.ToArray();//得到加密后的字節數組
            cs.Close();
            ms.Close();
            return cipherBytes;
        }

        /// <summary>
        /// AES解密
        /// </summary>
        /// <param name="cipherText">密文字節數組</param>
        /// <param name="strKey">密鑰</param>
        /// <returns>返回解密后的字符串</returns>
        public static byte[] AESDecrypt(byte[] cipherText, string strKey)
        {
            SymmetricAlgorithm des = Rijndael.Create();
            des.Key = Encoding.UTF8.GetBytes(strKey);
            des.IV = _key1;
            byte[] decryptBytes = new byte[cipherText.Length];
            MemoryStream ms = new MemoryStream(cipherText);
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Read);
            cs.Read(decryptBytes, 0, decryptBytes.Length);
            cs.Close();
            ms.Close();
            return decryptBytes;
        }

 

在和不同語言做解密解密對接的時間要注意對方使用的編碼格式、填充模式和運算模式，這幾點都是容易被忽略的，尤其是編碼格式。稍不注意就進坑了