Convert.ToBase64String(Encoding.Unicode.GetBytes(userName))
asp.net做的base64加密，在asp下如何解密？是不是用Unicode编码的不好解？要用ascii编码？
[解决办法]
Convert.FromBase64String ？？？
[解决办法]
Convert.ToBase64String，你用的这不都是吗
[解决办法]
base64解码很容易自己写。比如你可以从下帖的实现入手：
http://topic.csdn.net/u/20120202/10/f9e9bc8b-238c-479c-927b-1ac70657eb0d.html
[解决办法]
// by anzhiqiang add.2009-2-27.用于base64編碼与反編碼var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";var base64DecodeChars = new Array( -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);function base64encode(str) { var out, i, len; var c1, c2, c3; len = str.length; i = 0; out = ""; while(i < len) { c1 = str.charCodeAt(i++) & 0xff; if(i == len) { out += base64EncodeChars.charAt(c1 >> 2); out += base64EncodeChars.charAt((c1 & 0x3) << 4); out += "=="; break; } c2 = str.charCodeAt(i++); if(i == len) { out += base64EncodeChars.charAt(c1 >> 2); out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4)); out += base64EncodeChars.charAt((c2 & 0xF) << 2); out += "="; break; } c3 = str.charCodeAt(i++); out += base64EncodeChars.charAt(c1 >> 2); out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4)); out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6)); out += base64EncodeChars.charAt(c3 & 0x3F); } return out;}function base64decode(str) { var c1, c2, c3, c4; var i, len, out; len = str.length; i = 0; out = ""; while(i < len) { /* c1 */ do { c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff]; } while(i < len && c1 == -1); if(c1 == -1) break; /* c2 */ do { c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff]; } while(i < len && c2 == -1); if(c2 == -1) break; out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)); /* c3 */ do { c3 = str.charCodeAt(i++) & 0xff; if(c3 == 61) return out; c3 = base64DecodeChars[c3]; } while(i < len && c3 == -1); if(c3 == -1) break; out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2)); /* c4 */ do { c4 = str.charCodeAt(i++) & 0xff; if(c4 == 61) return out; c4 = base64DecodeChars[c4]; } while(i < len && c4 == -1); if(c4 == -1) break; out += String.fromCharCode(((c3 & 0x03) << 6) | c4); } return out;}function utf16to8(str) { var out, i, len, c; out = ""; len = str.length; for(i = 0; i < len; i++) { c = str.charCodeAt(i); if ((c >= 0x0001) && (c <= 0x007F)) { out += str.charAt(i); } else if (c > 0x07FF) { out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F)); out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F)); out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F)); } else { out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F)); out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F)); } } return out;}function utf8to16(str) { var out, i, len, c; var char2, char3; out = ""; len = str.length; i = 0; while(i < len) { c = str.charCodeAt(i++); switch(c >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: // 0xxxxxxx out += str.charAt(i-1); break; case 12: case 13: // 110x xxxx 10xx xxxx char2 = str.charCodeAt(i++); out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F)); break; case 14: // 1110 xxxx 10xx xxxx 10xx xxxx char2 = str.charCodeAt(i++); char3 = str.charCodeAt(i++); out += String.fromCharCode(((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0)); break; } } return out;}
[解决办法]
相应的C# base64
/********************************************************************************** Author: anzhiqiang** Created On: 05/18/2010 16:30** Comments: Encrypt&Decrypt component.*********************************************************************************/using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Web;using System.Web.Security;using System.Text.RegularExpressions;using System.Security.Cryptography;namespace EShipping.Common{ public class Security { public Security() { } /// <summary> /// 採用MD5或SHA1加密方式 /// </summary> /// <param name="PasswordString"></param> /// <param name="PasswordFormat"></param> /// <returns></returns> public static string EncryptPassword(string PasswordString, string PasswordFormat) { string EncryptPassword = ""; if (PasswordFormat == "SHA1") { EncryptPassword = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(PasswordString, "SHA1"); } else if (PasswordFormat == "MD5") { EncryptPassword = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(PasswordString, "MD5"); } return EncryptPassword; } #region BASE64 Encoding.by anzhiqiang add 2009-2-27 /// <summary> /// Encode64 /// </summary> /// <param name="Message"></param> /// <returns></returns> public string Encode64(string Message) { 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', '+', '/', '=' }; byte empty = (byte)0; System.Collections.ArrayList byteMessage = new System.Collections.ArrayList(System.Text.Encoding.Default.GetBytes (Message)); 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(); } /// <summary> /// Decode64 /// </summary> /// <param name="Message"></param> /// <returns></returns> public string Decode64(string Message) { if (Message == null || Message == "") { return null; } string Base64Code = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; int page = Message.Length / 4; System.Collections.ArrayList outMessage = new System.Collections.ArrayList(page * 3); char[] message = Message.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); } #endregion }}
[解决办法]
Base64不是加密，是编码，就是把二进制编码成可见字符，用于在网上传送。和原始二进制数据是Unicode，UTF-8，GB2312没有任何关系
算法都是固定的，任何语言都可以进行编码和解码，只不过有的标准类库提供，有的没有提供罢了。
[解决办法]
Base64编码啊。可以自己写一个的 a-Z 0-9 /= 什么的，也可以用别的东西。
这样来回编码/解码可以非常省劲的跨这个跨那个的。