地址栏加密

最新推荐文章于 2024-10-09 14:35:44 发布

gang027

最新推荐文章于 2024-10-09 14:35:44 发布

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CC 4.0 BY-SA版权

文章标签：加密 byte string null system class

本文链接：https://blog.youkuaiyun.com/gang027/article/details/1886804

本文介绍了一个使用C#实现的Base64加密解密类，该类提供了一种方法来将字符串转换为Base64编码格式，并能从Base64编码还原回原始字符串。代码详细展示了加密过程中的位操作以及如何处理不同长度的输入。

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C# code


using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

/// <summary>
/// Base64 的摘要说明
/// </summary>
public class Base64
{
    public Base64()
    {
        //
        // TODO: 在此处添加构造函数逻辑
        //
    }
    public static string EncryptString(string str)
    {
        if (str == null || str.Trim() == "")
        {
            return "";
        }
        else
        {
            try
            {
                char[] Base64Code = new char[] { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '@', '~', '^' };
                //char[] Base64Code = new char[] { '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '4', '5', '0', '4', '5', '6', '7', '8', '9', '8', '7', '7', '8', '5', '4', '3', '5', '2', '1', '0', '0', '1', '1', '1', '1', '1', '1', '2', '2', 'O', '3', '4', '5', '6', '6', '8', '9', '1', '2', '3', '5', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '4', '5', '6' };
                byte empty = (byte)0;
                System.Collections.ArrayList byteMessage = new System.Collections.ArrayList(System.Text.Encoding.Default.GetBytes(str));
                System.Text.StringBuilder outmessage;
                int messageLen = byteMessage.Count;
                int page = messageLen / 3;
                int use = 0;
                if ((use = messageLen % 3) > 0)
                {
                    for (int i = 0; i < 3 - use; i++)
                        byteMessage.Add(empty);
                    page++;
                }
                outmessage = new System.Text.StringBuilder(page * 4);
                for (int i = 0; i < page; i++)
                {
                    byte[] instr = new byte[3];
                    instr[0] = (byte)byteMessage[i * 3];
                    instr[1] = (byte)byteMessage[i * 3 + 1];
                    instr[2] = (byte)byteMessage[i * 3 + 2];
                    int[] outstr = new int[4];
                    outstr[0] = instr[0] >> 2;

                    outstr[1] = ((instr[0] & 0x03) << 4) ^ (instr[1] >> 4);
                    if (!instr[1].Equals(empty))
                        outstr[2] = ((instr[1] & 0x0f) << 2) ^ (instr[2] >> 6);
                    else
                        outstr[2] = 64;
                    if (!instr[2].Equals(empty))
                        outstr[3] = (instr[2] & 0x3f);
                    else
                        outstr[3] = 64;
                    outmessage.Append(Base64Code[outstr[0]]);
                    outmessage.Append(Base64Code[outstr[1]]);
                    outmessage.Append(Base64Code[outstr[2]]);
                    outmessage.Append(Base64Code[outstr[3]]);
                }
                return outmessage.ToString();
            }
            catch
            {
                return "";
            }
        }
    }
    public static string DecryptString(string str)
    {
        if (str == null || str.Trim() == "")
        {
            return "";
        }
        else
        {
            try
            {
                if ((str.Length % 4) != 0)
                {
                    throw new ArgumentException("不是正确的BASE64编码，请检查。", "str");
                }
                if (!System.Text.RegularExpressions.Regex.IsMatch(str, "^[A-Z0-9~@//^]*$", System.Text.RegularExpressions.RegexOptions.IgnoreCase))
                {
                    throw new ArgumentException("包含不正确的BASE64编码，请检查。", "str");
                }
                string Base64Code = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789@~^";
                int page = str.Length / 4;
                System.Collections.ArrayList outMessage = new System.Collections.ArrayList(page * 3);
                char[] message = str.ToCharArray();
                for (int i = 0; i < page; i++)
                {
                    byte[] instr = new byte[4];
                    instr[0] = (byte)Base64Code.IndexOf(message[i * 4]);
                    instr[1] = (byte)Base64Code.IndexOf(message[i * 4 + 1]);
                    instr[2] = (byte)Base64Code.IndexOf(message[i * 4 + 2]);
                    instr[3] = (byte)Base64Code.IndexOf(message[i * 4 + 3]);
                    byte[] outstr = new byte[3];
                    outstr[0] = (byte)((instr[0] << 2) ^ ((instr[1] & 0x30) >> 4));
                    if (instr[2] != 64)
                    {
                        outstr[1] = (byte)((instr[1] << 4) ^ ((instr[2] & 0x3c) >> 2));
                    }
                    else
                    {
                        outstr[2] = 0;
                    }
                    if (instr[3] != 64)
                    {
                        outstr[2] = (byte)((instr[2] << 6) ^ instr[3]);
                    }
                    else
                    {
                        outstr[2] = 0;
                    }
                    outMessage.Add(outstr[0]);
                    if (outstr[1] != 0)
                        outMessage.Add(outstr[1]);
                    if (outstr[2] != 0)
                        outMessage.Add(outstr[2]);
                }
                byte[] outbyte = (byte[])outMessage.ToArray(Type.GetType("System.Byte"));
                return System.Text.Encoding.Default.GetString(outbyte);
            }
            catch
            {
                return "";
            }
        }

    }
}