C#实现Base64加密解密

方法一

class Base64Helper
{
    /// <summary>
    /// Base64加密，采用utf8编码方式加密
    /// </summary>
    /// <param name="source">待加密的明文</param>
    /// <returns>加密后的字符串</returns>
    public static string Base64Encode(string source)
    {
        return Base64Encode(Encoding.UTF8, source);
    }

    /// <summary>
    /// Base64加密
    /// </summary>
    /// <param name="encodeType">加密采用的编码方式</param>
    /// <param name="source">待加密的明文</param>
    /// <returns></returns>
    public static string Base64Encode(Encoding encodeType, string source)
    {
        string encode = string.Empty;
        byte[] bytes = encodeType.GetBytes(source);
        try
        {
            encode = Convert.ToBase64String(bytes);
        }
        catch
        {
            encode = source;
        }
        return encode;
    }

    /// <summary>
    /// Base64解密，采用utf8编码方式解密
    /// </summary>
    /// <param name="result">待解密的密文</param>
    /// <returns>解密后的字符串</returns>
    public static string Base64Decode(string result)
    {
        return Base64Decode(Encoding.UTF8, result);
    }

    /// <summary>
    /// Base64解密
    /// </summary>
    /// <param name="encodeType">解密采用的编码方式，注意和加密时采用的方式一致</param>
    /// <param name="result">待解密的密文</param>
    /// <returns>解密后的字符串</returns>
    public static string Base64Decode(Encoding encodeType, string result)
    {
        string decode = string.Empty;
        byte[] bytes = Convert.FromBase64String(result);
        try
        {
            decode = encodeType.GetString(bytes);
        }
        catch
        {
            decode = result;
        }
        return decode;
    }
}

方法二

有一种加密方式：明文加密之后生成长度是24位的密文，而且密文以=结尾。经查询后发现大家都说这种加密方式是Base64加密，不过这种加密方式与方法一中的Base64加密不一样，具体代码如下。

class Program
{
    static void Main(string[] args)
    {
        string original = "123456";

        var md5 = BitConverter.ToString(new System.Security.Cryptography.MD5CryptoServiceProvider().ComputeHash(Encoding.Default.GetBytes(original))).Replace("-", "").ToLower();
        Console.WriteLine("md5=" + md5);

        //b64是以=结尾的长度为24位的密文
        var b64 = Convert.ToBase64String(new System.Security.Cryptography.MD5CryptoServiceProvider().ComputeHash(Encoding.Default.GetBytes(original)));
        Console.WriteLine("b64=" + b64);

        var dec = BitConverter.ToString(new System.Security.Cryptography.FromBase64Transform().TransformFinalBlock(Encoding.Default.GetBytes(b64), 0, Encoding.Default.GetBytes(b64).Length)).Replace("-","").ToLower();
        Console.WriteLine("dec=" + dec);
        Console.ReadLine();            
    }
}

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