C#对称加密（AES加密）每次生成的密文结果不同思路代码分享

public static string Encrypt(string plainText, string AESKey)
{
RijndaelManaged rijndaelCipher = new RijndaelManaged();
byte[] inputByteArray = Encoding.UTF8.GetBytes(plainText);//得到需要加密的字节数组
rijndaelCipher.Key = Convert.FromBase64String(AESKey);//加解密双方约定好密钥：AESKey
rijndaelCipher.GenerateIV();
byte[] keyIv = rijndaelCipher.IV;
byte[] cipherBytes = null;
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, rijndaelCipher.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
cipherBytes = ms.ToArray();//得到加密后的字节数组
cs.Close();
ms.Close();
}
}
var allEncrypt = new byte[keyIv.Length + cipherBytes.Length];
Buffer.BlockCopy(keyIv, 0, allEncrypt, 0, keyIv.Length);
Buffer.BlockCopy(cipherBytes, 0, allEncrypt, keyIv.Length * sizeof(byte), cipherBytes.Length);
return Convert.ToBase64String(allEncrypt);
}

public static string Decrypt(string showText, string AESKey)
{
string result = string.Empty;
try
{
byte[] cipherText = Convert.FromBase64String(showText);
int length = cipherText.Length;
SymmetricAlgorithm rijndaelCipher = Rijndael.Create();
rijndaelCipher.Key = Convert.FromBase64String(AESKey);//加解密双方约定好的密钥
byte[] iv = new byte[16];
Buffer.BlockCopy(cipherText, 0, iv, 0, 16);
rijndaelCipher.IV = iv;
byte[] decryptBytes = new byte[length - 16];
byte[] passwdText = new byte[length - 16];
Buffer.BlockCopy(cipherText, 16, passwdText, 0, length - 16);
using (MemoryStream ms = new MemoryStream(passwdText))
{
using (CryptoStream cs = new CryptoStream(ms, rijndaelCipher.CreateDecryptor(), CryptoStreamMode.Read))
{
cs.Read(decryptBytes, 0, decryptBytes.Length);
cs.Close();
ms.Close();
}
}
result = Encoding.UTF8.GetString(decryptBytes).Replace("\0", "");   ///将字符串后尾的'\0'去掉
}
catch { }
return result;
}

string jiaMi = MyAESTools.Encrypt(textBox1.Text, "abcdefgh12345678abcdefgh12345678");

string jieMi = MyAESTools.Decrypt(textBox3.Text, "abcdefgh12345678abcdefgh12345678");