.net 中的AES加密解密

一般我使用的第一种，使用32位Key加密的算法，代码如下

  "AesKey": "asfo44beh9zmeoivlkcmljfoacjfojsd"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace Ocelot
{
    public class AesHelper
    {
        /// <summary>
        ///  AES 加密
        /// </summary>
        /// <param name="str">明文（待加密）</param>
        /// <param name="key">密文(一般用32位字符就可以了，位数不对会报错)</param>
        /// <returns></returns>
        public static string AesEncrypt(string str, string key)
        {
            try
            {
                if (string.IsNullOrEmpty(str)) return null;
                Byte[] toEncryptArray = Encoding.UTF8.GetBytes(str);

                RijndaelManaged rm = new RijndaelManaged
                {
                    Key = Encoding.UTF8.GetBytes(key),
                    Mode = CipherMode.ECB,
                    Padding = PaddingMode.PKCS7
                };

                ICryptoTransform cTransform = rm.CreateEncryptor();
                Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
                return Convert.ToBase64String(resultArray);
            }
            catch(Exception ex)
            {
                return null;
            }
        }

        /// <summary>
        ///  AES 解密
        /// </summary>
        /// <param name="str">明文（待解密）</param>
        /// <param name="key">密文(一般用32位字符就可以了，位数不对会报错)</param>
        /// <returns></returns>
        public static string AesDecrypt(string str, string key)
        {
            try
            {
                if (string.IsNullOrEmpty(str)) return null;
                str = str.Replace(" ", "+");
                Byte[] toEncryptArray = Convert.FromBase64String(str);

                RijndaelManaged rm = new RijndaelManaged
                {
                    Key = Encoding.UTF8.GetBytes(key),
                    Mode = CipherMode.ECB,
                    Padding = PaddingMode.PKCS7
                };

                ICryptoTransform cTransform = rm.CreateDecryptor();
                Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

                return Encoding.UTF8.GetString(resultArray);
            }
            catch 
            {
                return "";
            }
        }
    }
}

下面还有两种

AES加密中向量长度是16个byte

密钥长度有三种：16，24，32   单位byte

AES的区块长度固定为128比特，密钥长度则可以是128(6byte*8b)，192(24*8)或256(32*8)比特；

加密后的输出要转为base64 ，为什么呢？因为base64所有字符都是可打印，加密后的字符转为base64才能被人看见，在复制时候不容易漏掉

在C#中AES加密解密写法有：

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

/// <summary>
        /// AES解密
        /// </summary>
        /// <param name="decryptString">AES密文</param>
        /// <param name="key">秘钥（44个字符）</param>
        /// <param name="ivString">向量（16个字符）</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">秘钥（44个字符）</param>
        /// <param name="ivString">向量长度（16个字符）</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）和运算模式(Mode)也可以自定义，不同的值有不同的结果

下面是另一种写法

/// <summary>
        /// AES加密算法
        /// </summary>
        /// <param name="plainText">明文字符串</param>
        /// <param name="strKey">密钥</param>
        /// <returns>返回加密后的密文字节数组</returns>
        public static byte[] AESEncrypt(string plainText, string strKey)
        {
            //分组加密算法
            SymmetricAlgorithm des = Rijndael.Create();
            byte[] inputByteArray = Encoding.UTF8.GetBytes(plainText);//得到需要加密的字节数组
                                                                      //设置密钥及密钥向量
            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();//得到加密后的字节数组
            cs.Close();
            ms.Close();
            return cipherBytes;
        }

        /// <summary>
        /// AES解密
        /// </summary>
        /// <param name="cipherText">密文字节数组</param>
        /// <param name="strKey">密钥</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;
        }

在和不同语言做解密解密对接的时间要注意对方使用的编码格式、填充模式和运算模式，这几点都是容易被忽略的，尤其是编码格式。稍不注意就进坑了

博文来自：https://www.cnblogs.com/netqq/articles/9655115.html