第三方的加密規則約定：加密經過3DES加密后的Base64 編碼
最近在對接一個第三方接口，請求參數和響應參數全采用3des加密規則，由於我是用.NET對接的，而第三方是Java開發的，所以兩種程序之間采用的算法有一點差異，java的3des加密采用的是"DESede/CBC/PKCS5Padding"規則，所以對應的C#規則是"PaddingMode.PKCS7和CipherMode.CBC"，使用CBC模式的話在C#下必須傳入加密向量IV(固定長度8位)，默認"12345678"，加密密鑰和IV雙方約定好即可，如果是ECB編碼模式，那么就無須使用加密向量。
C#代碼如下：
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
namespace TCWireless.Utility
{
public class DESHelper
{
#region 3des加密
/// <summary>
/// 3des ecb模式加密
/// </summary>
/// <param name="aStrString">待加密的字符串</param>
/// <param name="aStrKey">密鑰</param>
/// <param name="iv">加密矢量：只有在CBC解密模式下才適用</param>
/// <param name="mode">運算模式</param>
/// <returns>加密后的字符串</returns>
public static string Encrypt3Des(string aStrString, string aStrKey, CipherMode mode = CipherMode.ECB, string iv = "12345678")
{
try
{
var des = new TripleDESCryptoServiceProvider
{
Key = Encoding.UTF8.GetBytes(aStrKey),
Mode = mode
};
if (mode == CipherMode.CBC)
{
des.IV = Encoding.UTF8.GetBytes(iv);
}
var desEncrypt = des.CreateEncryptor();
byte[] buffer = Encoding.UTF8.GetBytes(aStrString);
return Convert.ToBase64String(desEncrypt.TransformFinalBlock(buffer, 0, buffer.Length));
}
catch (Exception e)
{
return string.Empty;
}
}
#endregion
#region 3des解密
/// <summary>
/// des 解密
/// </summary>
/// <param name="aStrString">加密的字符串</param>
/// <param name="aStrKey">密鑰</param>
/// <param name="iv">解密矢量：只有在CBC解密模式下才適用</param>
/// <param name="mode">運算模式</param>
/// <returns>解密的字符串</returns>
public static string Decrypt3Des(string aStrString, string aStrKey, CipherMode mode = CipherMode.ECB, string iv = "12345678")
{
try
{
var des = new TripleDESCryptoServiceProvider
{
Key = Encoding.UTF8.GetBytes(aStrKey),
Mode = mode,
Padding = PaddingMode.PKCS7
};
if (mode == CipherMode.CBC)
{
des.IV = Encoding.UTF8.GetBytes(iv);
}
var desDecrypt = des.CreateDecryptor();
var result = "";
byte[] buffer = Convert.FromBase64String(aStrString);
result = Encoding.UTF8.GetString(desDecrypt.TransformFinalBlock(buffer, 0, buffer.Length));
return result;
}
catch (Exception e)
{
return string.Empty;
}
}
#endregion
}
}