293 lines
8.9 KiB
C#
293 lines
8.9 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Text;
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namespace WinformGeneralDeveloperFrame.Commons
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{
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/// <summary>
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/// 基于Base64的加密编码辅助类，
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/// 可以设置不同的密码表来获取不同的编码与解码
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/// </summary>
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public class Base64Util
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{
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/// <summary>
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/// 构造函数，初始化编码表
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/// </summary>
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public Base64Util()
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{
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this.InitDict();
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}
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protected static Base64Util s_b64 = new Base64Util();
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/// <summary>
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/// 使用默认的密码表加密字符串
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/// </summary>
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/// <param name="input">待加密字符串</param>
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/// <returns></returns>
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public static string Encrypt(string input)
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{
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return s_b64.Encode(input);
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}
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/// <summary>
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/// 使用默认的密码表解密字符串
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/// </summary>
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/// <param name="input">待解密字符串</param>
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/// <returns></returns>
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public static string Decrypt(string input)
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{
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return s_b64.Decode(input);
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}
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/// <summary>
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/// 获取具有标准的Base64密码表的加密类
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/// </summary>
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/// <returns></returns>
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public static Base64Util GetStandardBase64()
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{
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Base64Util b64 = new Base64Util();
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b64.Pad = "=";
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b64.CodeTable = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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return b64;
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}
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protected string m_codeTable = @"ABCDEFGHIJKLMNOPQRSTUVWXYZbacdefghijklmnopqrstu_wxyz0123456789*-";
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protected string m_pad = "v";
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protected Dictionary<int, char> m_t1 = new Dictionary<int, char>();
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protected Dictionary<char, int> m_t2 = new Dictionary<char, int>();
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/// <summary>
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/// 密码表
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/// </summary>
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public string CodeTable
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{
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get { return m_codeTable; }
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set
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{
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if (value == null)
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{
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throw new Exception("密码表不能为null");
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}
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else if (value.Length < 64)
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{
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throw new Exception("密码表长度必须至少为64");
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}
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else
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{
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this.ValidateRepeat(value);
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this.ValidateEqualPad(value, m_pad);
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m_codeTable = value;
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this.InitDict();
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}
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}
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}
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/// <summary>
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/// 补码
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/// </summary>
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public string Pad
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{
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get { return m_pad; }
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set
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{
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if (value == null)
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{
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throw new Exception("密码表的补码不能为null");
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}
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else if (value.Length != 1)
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{
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throw new Exception("密码表的补码长度必须为1");
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}
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else
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{
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this.ValidateEqualPad(m_codeTable, value);
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m_pad = value;
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this.InitDict();
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}
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}
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}
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/// <summary>
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/// 返回编码后的字符串
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/// </summary>
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/// <param name="source">原字符串</param>
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/// <returns></returns>
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public string Encode(string source)
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{
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if (source == null || source == "")
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{
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return "";
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}
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else
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{
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StringBuilder sb = new StringBuilder();
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byte[] tmp = System.Text.UTF8Encoding.UTF8.GetBytes(source);
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int remain = tmp.Length % 3;
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int patch = 3 - remain;
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if (remain != 0)
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{
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Array.Resize(ref tmp, tmp.Length + patch);
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}
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int cnt = (int)Math.Ceiling(tmp.Length * 1.0 / 3);
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for (int i = 0; i < cnt; i++)
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{
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sb.Append(this.EncodeUnit(tmp[i * 3], tmp[i * 3 + 1], tmp[i * 3 + 2]));
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}
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if (remain != 0)
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{
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sb.Remove(sb.Length - patch, patch);
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for (int i = 0; i < patch; i++)
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{
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sb.Append(m_pad);
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}
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}
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return sb.ToString();
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}
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}
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protected string EncodeUnit(params byte[] unit)
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{
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int[] obj = new int[4];
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obj[0] = (unit[0] & 0xfc) >> 2;
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obj[1] = ((unit[0] & 0x03) << 4) + ((unit[1] & 0xf0) >> 4);
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obj[2] = ((unit[1] & 0x0f) << 2) + ((unit[2] & 0xc0) >> 6);
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obj[3] = unit[2] & 0x3f;
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StringBuilder sb = new StringBuilder();
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for (int i = 0; i < obj.Length; i++)
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{
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sb.Append(this.GetEC((int)obj[i]));
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}
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return sb.ToString();
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}
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protected char GetEC(int code)
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{
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return m_t1[code];//m_codeTable[code];
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}
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/// <summary>
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/// 获得解码字符串
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/// </summary>
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/// <param name="source">原字符串</param>
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/// <returns></returns>
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public string Decode(string source)
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{
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if (source == null || source == "")
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{
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return "";
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}
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else
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{
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List<byte> list = new List<byte>();
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char[] tmp = source.ToCharArray();
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int remain = tmp.Length % 4;
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if (remain != 0)
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{
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Array.Resize(ref tmp, tmp.Length - remain);
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}
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int patch = source.IndexOf(m_pad);
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if (patch != -1)
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{
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patch = source.Length - patch;
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}
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int cnt = tmp.Length / 4;
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for (int i = 0; i < cnt; i++)
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{
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this.DecodeUnit(list, tmp[i * 4], tmp[i * 4 + 1], tmp[i * 4 + 2], tmp[i * 4 + 3]);
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}
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for (int i = 0; i < patch; i++)
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{
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list.RemoveAt(list.Count - 1);
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}
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return System.Text.Encoding.UTF8.GetString(list.ToArray());
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}
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}
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protected void DecodeUnit(List<byte> byteArr, params char[] chArray)
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{
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int[] res = new int[3];
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byte[] unit = new byte[chArray.Length];
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for (int i = 0; i < chArray.Length; i++)
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{
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unit[i] = this.FindChar(chArray[i]);
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}
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res[0] = (unit[0] << 2) + ((unit[1] & 0x30) >> 4);
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res[1] = ((unit[1] & 0xf) << 4) + ((unit[2] & 0x3c) >> 2);
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res[2] = ((unit[2] & 0x3) << 6) + unit[3];
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for (int i = 0; i < res.Length; i++)
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{
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byteArr.Add((byte)res[i]);
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}
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}
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protected byte FindChar(char ch)
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{
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int pos = m_t2[ch];//m_codeTable.IndexOf(ch);
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return (byte)pos;
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}
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/// <summary>
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/// 初始化双向哈希字典
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/// </summary>
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protected void InitDict()
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{
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m_t1.Clear();
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m_t2.Clear();
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m_t2.Add(m_pad[0], -1);
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for (int i = 0; i < m_codeTable.Length; i++)
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{
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m_t1.Add(i, m_codeTable[i]);
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m_t2.Add(m_codeTable[i], i);
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}
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}
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/// <summary>
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/// 检查字符串中的字符是否有重复
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/// </summary>
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/// <param name="input">待检查字符串</param>
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/// <returns></returns>
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protected void ValidateRepeat(string input)
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{
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for (int i = 0; i < input.Length; i++)
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{
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if (input.LastIndexOf(input[i]) > i)
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{
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throw new Exception("密码表中含有重复字符：" + input[i]);
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}
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}
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}
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/// <summary>
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/// 检查字符串是否包含补码字符
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/// </summary>
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/// <param name="input">待检查字符串</param>
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/// <param name="pad"></param>
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protected void ValidateEqualPad(string input, string pad)
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{
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if (input.IndexOf(pad) > -1)
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{
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throw new Exception("密码表中包含了补码字符：" + pad);
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}
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}
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/// <summary>
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/// 测试
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/// </summary>
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protected void Test()
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{
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//m_codeTable = @"STUVWXYZbacdefghivklABCDEFGHIJKLMNOPQRmnopqrstu!wxyz0123456789+/";
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//m_pad = "j";
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this.InitDict();
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string test = "abc ABC 你好！◎＃￥％……!@#$%^";
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string encode = this.Encode("false");
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string decode = this.Decode(encode);
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Console.WriteLine(encode);
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Console.WriteLine(test == decode);
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}
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}
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}
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