发信人: gzcjh()
整理人: i_am_trueman(2003-10-22 17:01:37), 站内信件
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一般来说，口令的加密是采用单向加密的方式，如哈希(HASH)算法（就是说加密
过的明文是不能由密文还原出来的），这样做的好处是保存在数据库中的密文即
使泄漏，人家没法还原，也就没法实现冒充身份。要知道，现在很多人都是不同
的地方使用同一个口令，口令一旦泄漏，损失就惨重了。而要检测用户输入的口
令是否正确，只需要把用户输入的口令再进行一次单向加密，和数据库中的比较
就可以了。
哈希算法常用的有 MD2->MD3->MD4->MD5->SHA1，强度由弱到强，当然速度由快到
慢，现在用得最多的是 MD5 和 SHA1，下面提供一种在 ASP 中用存脚本实现 MD
5 算法的程序，和大家交流交流。
如果你是使用独立主机的用户，可以直接调用 Microsoft 提供的 CryptAPI 函数
库（服务器端安装了 IE3 以上就带有这个库了），速度会快很多，而且加密解密
的方式也多很多（包括著名的 RSA、DES、Blowfish 等），详细的使用方法参看
MSDN。
使用时将这个文件 Include 到你的程序中，调用 calcMD5(明文) 就可以得到密
文了，返回值是 32 个 16 进制数（0-F），加起来是128位二进制数。
<SCRIPT RUNAT=SERVER LANGUAGE="JSCRIPT">
/*
MD5 算法。
文件：md5.asp
Copyright(C) 2000 Allrights reserved
*/
var sAscii = " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUV
WXYZ"
var sAscii = sAscii + "[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~";
var sHex = "0123456789ABCDEF";
function hex(i)
{
h = "";
for(j = 0; j <= 3; j++)
{
h += sHex.charAt((i >> (j * 8 + 4)) & 0x0F) +
sHex.charAt((i >> (j * 8)) & 0x0F);
}
return h;
}
function add(x, y)
{
return ((x&0x7FFFFFFF) + (y&0x7FFFFFFF)) ^ (x&0x80000000) ^ (y&0x800
00000);
}
function R1(A, B, C, D, X, S, T)
{
q = add(add(A, (B & C) | (~B & D)), add(X, T));
return add((q << S) | ((q >> (32 - S)) & (Math.pow(2, S) - 1)), B);
}
function R2(A, B, C, D, X, S, T)
{
q = add(add(A, (B & D) | (C & ~D)), add(X, T));
return add((q << S) | ((q >> (32 - S)) & (Math.pow(2, S) - 1)), B);
}
function R3(A, B, C, D, X, S, T)
{
q = add(add(A, B ^ C ^ D), add(X, T));
return add((q << S) | ((q >> (32 - S)) & (Math.pow(2, S) - 1)), B);
}
function R4(A, B, C, D, X, S, T)
{
q = add(add(A, C ^ (B | ~D)), add(X, T));
return add((q << S) | ((q >> (32 - S)) & (Math.pow(2, S) - 1)), B);
}
function calcMD5(sInp) {
wLen = (((sInp.length + 8) >> 6) + 1) << 4;
var X = new Array(wLen);
j = 4;
for (i = 0; (i * 4) < sInp.length; i++)
{
X[i] = 0;
for (j = 0; (j < 4) && ((j + i * 4) < sInp.length); j++)
{
X[i] += (sAscii.indexOf(sInp.charAt((i * 4) + j)) + 32) << (j *
8);
}
}
if (j == 4)
{
X[i++] = 0x80;
}
else
{
X[i - 1] += 0x80 << (j * 8);
}
for(; i < wLen; i++) { X[i] = 0; }
X[wLen - 2] = sInp.length * 8;
a = 0x67452301;
b = 0xefcdab89;
c = 0x98badcfe;
d = 0x10325476;
for (i = 0; i < wLen; i += 16) {
aO = a;
bO = b;
cO = c;
dO = d;
a = R1(a, b, c, d, X[i+ 0], 7 , 0xd76aa478);
d = R1(d, a, b, c, X[i+ 1], 12, 0xe8c7b756);
c = R1(c, d, a, b, X[i+ 2], 17, 0x242070db);
b = R1(b, c, d, a, X[i+ 3], 22, 0xc1bdceee);
a = R1(a, b, c, d, X[i+ 4], 7 , 0xf57c0faf);
d = R1(d, a, b, c, X[i+ 5], 12, 0x4787c62a);
c = R1(c, d, a, b, X[i+ 6], 17, 0xa8304613);
b = R1(b, c, d, a, X[i+ 7], 22, 0xfd469501);
a = R1(a, b, c, d, X[i+ 8], 7 , 0x698098d8);
d = R1(d, a, b, c, X[i+ 9], 12, 0x8b44f7af);
c = R1(c, d, a, b, X[i+10], 17, 0xffff5bb1);
b = R1(b, c, d, a, X[i+11], 22, 0x895cd7be);
a = R1(a, b, c, d, X[i+12], 7 , 0x6b901122);
d = R1(d, a, b, c, X[i+13], 12, 0xfd987193);
c = R1(c, d, a, b, X[i+14], 17, 0xa679438e);
b = R1(b, c, d, a, X[i+15], 22, 0x49b40821);
a = R2(a, b, c, d, X[i+ 1], 5 , 0xf61e2562);
d = R2(d, a, b, c, X[i+ 6], 9 , 0xc040b340);
c = R2(c, d, a, b, X[i+11], 14, 0x265e5a51);
b = R2(b, c, d, a, X[i+ 0], 20, 0xe9b6c7aa);
a = R2(a, b, c, d, X[i+ 5], 5 , 0xd62f105d);
d = R2(d, a, b, c, X[i+10], 9 , 0x2441453);
c = R2(c, d, a, b, X[i+15], 14, 0xd8a1e681);
b = R2(b, c, d, a, X[i+ 4], 20, 0xe7d3fbc8);
a = R2(a, b, c, d, X[i+ 9], 5 , 0x21e1cde6);
d = R2(d, a, b, c, X[i+14], 9 , 0xc33707d6);
c = R2(c, d, a, b, X[i+ 3], 14, 0xf4d50d87);
b = R2(b, c, d, a, X[i+ 8], 20, 0x455a14ed);
a = R2(a, b, c, d, X[i+13], 5 , 0xa9e3e905);
d = R2(d, a, b, c, X[i+ 2], 9 , 0xfcefa3f8);
c = R2(c, d, a, b, X[i+ 7], 14, 0x676f02d9);
b = R2(b, c, d, a, X[i+12], 20, 0x8d2a4c8a);
a = R3(a, b, c, d, X[i+ 5], 4 , 0xfffa3942);
d = R3(d, a, b, c, X[i+ 8], 11, 0x8771f681);
c = R3(c, d, a, b, X[i+11], 16, 0x6d9d6122);
b = R3(b, c, d, a, X[i+14], 23, 0xfde5380c);
a = R3(a, b, c, d, X[i+ 1], 4 , 0xa4beea44);
d = R3(d, a, b, c, X[i+ 4], 11, 0x4bdecfa9);
c = R3(c, d, a, b, X[i+ 7], 16, 0xf6bb4b60);
b = R3(b, c, d, a, X[i+10], 23, 0xbebfbc70);
a = R3(a, b, c, d, X[i+13], 4 , 0x289b7ec6);
d = R3(d, a, b, c, X[i+ 0], 11, 0xeaa127fa);
c = R3(c, d, a, b, X[i+ 3], 16, 0xd4ef3085);
b = R3(b, c, d, a, X[i+ 6], 23, 0x4881d05);
a = R3(a, b, c, d, X[i+ 9], 4 , 0xd9d4d039);
d = R3(d, a, b, c, X[i+12], 11, 0xe6db99e5);
c = R3(c, d, a, b, X[i+15], 16, 0x1fa27cf8);
b = R3(b, c, d, a, X[i+ 2], 23, 0xc4ac5665);
a = R4(a, b, c, d, X[i+ 0], 6 , 0xf4292244);
d = R4(d, a, b, c, X[i+ 7], 10, 0x432aff97);
c = R4(c, d, a, b, X[i+14], 15, 0xab9423a7);
b = R4(b, c, d, a, X[i+ 5], 21, 0xfc93a039);
a = R4(a, b, c, d, X[i+12], 6 , 0x655b59c3);
d = R4(d, a, b, c, X[i+ 3], 10, 0x8f0ccc92);
c = R4(c, d, a, b, X[i+10], 15, 0xffeff47d);
b = R4(b, c, d, a, X[i+ 1], 21, 0x85845dd1);
a = R4(a, b, c, d, X[i+ 8], 6 , 0x6fa87e4f);
d = R4(d, a, b, c, X[i+15], 10, 0xfe2ce6e0);
c = R4(c, d, a, b, X[i+ 6], 15, 0xa3014314);
b = R4(b, c, d, a, X[i+13], 21, 0x4e0811a1);
a = R4(a, b, c, d, X[i+ 4], 6 , 0xf7537e82);
d = R4(d, a, b, c, X[i+11], 10, 0xbd3af235);
c = R4(c, d, a, b, X[i+ 2], 15, 0x2ad7d2bb);
b = R4(b, c, d, a, X[i+ 9], 21, 0xeb86d391);
a = add(a, aO);
b = add(b, bO);
c = add(c, cO);
d = add(d, dO);
}
return hex(a) + hex(b) + hex(c) + hex(d);
}
</SCRIPT>
--
※ 来源:．月光软件站 http://www.moon-soft.com．[FROM: 61.140.226.23]
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