c# - 如何使用20byte key 进入AES ECB模式

如何使用20字节密钥（不能更改密钥）解密加密的文本“ debac58d0bc8526339678667bca923e15a7106a0c16c8148bd1468cefad57762ccf53a4a780bc27748c5583a02c41dee”，密钥“ qwertyuioplkj＃”，“ php”，“”，“”，“”，“”，“”，“，

最佳答案

好的，这是C＃中的解决方案，它仅支持最大32个字节且低至0个字节的键的任何键密钥。

Ideone示例：https://ideone.com/XONRBf

解决方案的屏幕截图：



下面的C＃源代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.Globalization;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            String cryptedText = "debac58d0bc8526339678667bca923e15a7106a0c16c8148bd1468cefad57762ccf53a4a780bc27748c5583a02c41dee";
            String key = "qwertyuioplkjhgfdsaz";
            Console.WriteLine("Crypted Text = " + cryptedText);
            Console.WriteLine("Key = " + key);
            Console.WriteLine("Decrypted = " + Decrypt(cryptedText, key));
            Console.ReadKey();
        }

        public static string Decrypt(string toDecrypt, string key)
        {
            byte[] keyArray = UTF8Encoding.UTF8.GetBytes(key); // AES-256 key
            PadToMultipleOf(ref keyArray, 8);
            //byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);
            byte[] toEncryptArray = ConvertHexStringToByteArray(toDecrypt);

            RijndaelManaged rDel = new RijndaelManaged();
            rDel.KeySize = (keyArray.Length * 8);
            rDel.Key = keyArray;          // in bits
            rDel.Mode = CipherMode.ECB; // http://msdn.microsoft.com/en-us/library/system.security.cryptography.ciphermode.aspx
            rDel.Padding = PaddingMode.None;  // better lang support
            ICryptoTransform cTransform = rDel.CreateDecryptor();
            byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
            return UTF8Encoding.UTF8.GetString(resultArray);
        }

        public static void PadToMultipleOf(ref byte[] src, int pad)
        {
            int len = (src.Length + pad - 1) / pad * pad;
            Array.Resize(ref src, len);
        }

        public static byte[] ConvertHexStringToByteArray(string hexString)
        {
            if (hexString.Length % 2 != 0)
            {
                throw new ArgumentException(String.Format(CultureInfo.InvariantCulture, "The binary key cannot have an odd number of digits: {0}", hexString));
            }

            byte[] HexAsBytes = new byte[hexString.Length / 2];
            for (int index = 0; index < HexAsBytes.Length; index++)
            {
                string byteValue = hexString.Substring(index * 2, 2);
                HexAsBytes[index] = byte.Parse(byteValue, NumberStyles.HexNumber, CultureInfo.InvariantCulture);
            }

            return HexAsBytes;
        }
    }
}