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Generate a Hash from string in Javascript/jQuery
Can anyone suggest a simple (i.e. tens of lines of code, not hundreds of lines) hash function written in (browser-compatible) JavaScript? Ideally I'd like something that, when passed a string as input, produces something similar to the 32 character hexadecimal string that's the typical output of MD5, SHA1, etc. It doesn't have to be cryptographically secure, just reasonably resistant to collisions. (My initial use case is URLs, but I'll probably want to use it on other strings in the future.)
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javascript
hash
md5
sha1
Check out this MD5 implementation for JavaScript. Its BSD Licensed and really easy to use. Example:
md5 = hex_md5("message to digest")
// Simple but unreliable function to create string hash by Sergey.Shuchkin [t] gmail.com
// alert( strhash('http://www.w3schools.com/js/default.asp') ); // 6mn6tf7st333r2q4o134o58888888888
function strhash( str ) {
if (str.length % 32 > 0) str += Array(33 - str.length % 32).join("z");
var hash = '', bytes = [], i = j = k = a = 0, dict = ['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','1','2','3','4','5','6','7','8','9'];
for (i = 0; i < str.length; i++ ) {
ch = str.charCodeAt(i);
bytes[j++] = (ch < 127) ? ch & 0xFF : 127;
}
var chunk_len = Math.ceil(bytes.length / 32);
for (i=0; i<bytes.length; i++) {
j += bytes[i];
k++;
if ((k == chunk_len) || (i == bytes.length-1)) {
a = Math.floor( j / k );
if (a < 32)
hash += '0';
else if (a > 126)
hash += 'z';
else
hash += dict[ Math.floor( (a-32) / 2.76) ];
j = k = 0;
}
}
return hash;
}
Check out these implementations
There are many realizations of hash functions written in JS. For example:
If you don't need security, you can also use base64 which is not hash-function, has not fixed output and could be simply decoded by user, but looks more lightweight and could be used for hide values: http://www.webtoolkit.info/javascript-base64.html
Simple object hasher:
(function () {
Number.prototype.toHex = function () {
var ret = ((this<0?0x8:0)+((this >> 28) & 0x7)).toString(16) + (this & 0xfffffff).toString(16);
while (ret.length < 8) ret = '0'+ret;
return ret;
};
Object.hashCode = function hashCode(o, l) {
l = l || 2;
var i, c, r = [];
for (i=0; i<l; i++)
r.push(i*268803292);
function stringify(o) {
var i,r;
if (o === null) return 'n';
if (o === true) return 't';
if (o === false) return 'f';
if (o instanceof Date) return 'd:'+(0+o);
i=typeof o;
if (i === 'string') return 's:'+o.replace(/([\\\\;])/g,'\\$1');
if (i === 'number') return 'n:'+o;
if (o instanceof Function) return 'm:'+o.toString().replace(/([\\\\;])/g,'\\$1');
if (o instanceof Array) {
r=[];
for (i=0; i<o.length; i++)
r.push(stringify(o[i]));
return 'a:'+r.join(';');
}
r=[];
for (i in o) {
r.push(i+':'+stringify(o[i]))
}
return 'o:'+r.join(';');
}
o = stringify(o);
for (i=0; i<o.length; i++) {
for (c=0; c<r.length; c++) {
r[c] = (r[c] << 13)-(r[c] >> 19);
r[c] += o.charCodeAt(i) << (r[c] % 24);
r[c] = r[c] & r[c];
}
}
for (i=0; i<r.length; i++) {
r[i] = r[i].toHex();
}
return r.join('');
}
}());
The meat here is the stringifier, which simply converts any object into a unique string. hashCode then runs over the object, hashing together the characters of the stringified object.
For extra points, export the stringifier and create a parser.
Source: Stackoverflow.com