Encrypting Data in JavaScript Using the SHA-1 Algorithm

Password Chameleon, the offline generator for site-specific passwords, uses the SHA-1 algorithm implemented in JavaScript to generate the hash (or the unique password).

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* A JavaScript implementation of the Secure Hash Algorithm, SHA-1,

* as defined in FIPS PUB 180-1

* Version 2.1 Copyright Paul Johnston 2000 - 2002.

* Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet

* Distributed under the BSD License

* See http://pajhome.org.uk/crypt/md5 for details.

var b64pad = "";

var chrsz = 8;

function generate(secretpassword, sitename) {

var pwd = "";

var error = "";

if (sitename.length == 0)

error = error + " sitename";

if (secretpassword.length == 0)

error = error + " secretpassword";

if (error.length == 0) {

var input = secretpassword + ':' + sitename.toLowerCase();

pwd = binb2b64(core_sha1(str2binb(input), input.length * chrsz));

pwd = pwd.substring(0, 10);

pwd = ensurenumberandletter(pwd);

}

return { password: pwd, error: error };

}

function core_sha1(x, len)

{

x[len >> 5] |= 0x80 << (24 - len % 32);

x[((len + 64 >> 9) << 4) + 15] = len;

var w = Array(80);

var a = 1732584193;

var b = -271733879;

var c = -1732584194;

var d = 271733878;

var e = -1009589776;

for(var i = 0; i < x.length; i += 16)

{

var olda = a;

var oldb = b;

var oldc = c;

var oldd = d;

var olde = e;

for(var j = 0; j < 80; j++)

{

if(j < 16) w[j] = x[i + j];

else w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);

var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),

safe_add(safe_add(e, w[j]), sha1_kt(j)));

e = d;

d = c;

c = rol(b, 30);

b = a;

a = t;

}

a = safe_add(a, olda);

b = safe_add(b, oldb);

c = safe_add(c, oldc);

d = safe_add(d, oldd);

e = safe_add(e, olde);

}

return Array(a, b, c, d, e);

}

function sha1_ft(t, b, c, d)

{

if(t < 20) return (b & c) | ((~b) & d);

if(t < 40) return b ^ c ^ d;

if(t < 60) return (b & c) | (b & d) | (c & d);

return b ^ c ^ d;

}

function sha1_kt(t)

{

return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 :

(t < 60) ? -1894007588 : -899497514;

}

function safe_add(x, y)

{

var lsw = (x & 0xFFFF) + (y & 0xFFFF);

var msw = (x >> 16) + (y >> 16) + (lsw >> 16);

return (msw << 16) | (lsw & 0xFFFF);

}

function rol(num, cnt)

{

return (num << cnt) | (num >>> (32 - cnt));

}

function str2binb(str)

{

var bin = Array();

var mask = (1 << chrsz) - 1;

for(var i = 0; i < str.length * chrsz; i += chrsz)

bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (24 - i%32);

return bin;

}

function binb2b64(binarray)

{

var tab = "ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz123456789?!#@&$";

var str = "";

for(var i = 0; i < binarray.length * 4; i += 3)

{

var triplet = (((binarray[i >> 2] >> 8 * (3 - i%4)) & 0xFF) << 16)

| (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )

| ((binarray[i+2 >> 2] >> 8 * (3 - (i+2)%4)) & 0xFF);

for(var j = 0; j < 4; j++)

{

if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;

else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);

}

return str;

}

function ensurenumberandletter(s) {

var numbers = "123456789";

var letters = "ABCDEFGHIJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";

var punct = "?!#@&$";

var hasnumber = 0;

var hasletter = 0;

var haspunct = 0;

for (var i = 0; i < s.length; i++) {

if (numbers.indexOf(s[i]) > -1)

hasnumber = 1;

if (letters.indexOf(s[i]) > -1)

hasletter = 1;

if (punct.indexOf(s[i]) > -1)

haspunct = 1;

}

if (hasnumber == 0)

s = "1" + s.substring(1);

if (hasletter == 0)

s = s.substring(0, 1) + "a" + s.substring(2);

if (haspunct == 0)

s = s.substring(0, 2) + "@" + s.substring(3);

return s;

}

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Encrypting Data in JavaScript Using the SHA-1 Algorithm