Hash a string with the SHA-1 algorithm (using MooTools)

String.SHA1.js

/*
---
script: String.SHA1.js

description: Hash a string with the SHA-1 algorithm

license: MIT-style license.

authors: Yannick Croissant

inspiration:
  - [SHA-1 pseudocode](http://en.wikipedia.org/wiki/SHA-1#SHA-1_pseudocode)

requires:
 core/1.3: '*'
 more/1.3.1: [String.Extras]

provides: [String.SHA1]

...
*/

String.implement({
	
	SHA1:function(){
		// Initialize variables
		var	h0 = 1732584193,
			h1 = 4023233417,
			h2 = 2562383102,
			h3 = 271733878,
			h4 = 3285377520,
			p = '',
			s = this.length,
			// A little function to convert a number into hexadecimal
			hex = function(num){
				for(var a = 7, b=''; a >= 0; a--) b += ((num >>> (a * 4)) & 15).toString(16);
				return b;
			};
		
		// Convert the string into binary
		for (var i = 0; i < s ; i++) p += ('0000000' + this.charCodeAt(i).toString(2)).substr(-8);

		p += 1; // Append the bit '1' to the message
		
		// Append 0 <= k < 512 bits '0', so that the resulting message length (in bits) is congruent to 448 = -64 (mod 512)
		var k = (p.length - 448) % 512;
		p += '0'.repeat(k < 0 ? -1 * k : 512 - k);
		// Append length of message (before pre-processing), in bits, as 64-bit big-endian integer
		p += ('0'.repeat(63) + parseInt(s * 8, 10).toString(2)).substr(-64);
		
		var	v = [],
			m,
			t = p.length / 512;
		
		 // Break message into 512-bit chunks
		for (i = k = 0; m = p.substr(i, 512); i = i + 512) v[k++] = m;
		
		for (var o = 0; o < t; o++){
			var w = [],
				j;
			
			// Break chunk into sixteen 32-bit big-endian words w[i], 0 = i = 15
			for (i = k = 0; j = v[o].substr(k, 32); k += 32) w[i++] = parseInt(parseInt(j, 2), 10);
			
			// Extend the sixteen 32-bit words into eighty 32-bit words
			for (i = 16; i < 80; i++){
				w[i] = w[i - 3]^w[i - 8]^w[i - 14]^w[i - 16];
				w[i] = (w[i] << 1) | (w[i] >>> (32 - 1))
			}
			
			// Initialize hash value for this chunk
			var	a = h0,
				b = h1,
				c = h2,
				d = h3,
				e = h4,
				f,
				k,
				temp;
			
			// Main loop
			for (i = 0; i < 80; i++){
				if (i >= 0 && i <= 19){
					f = (b & c) | (~b & d);
					k = 1518500249;
				} else if (i >= 20 && i <= 39){
					f = b^c^d;
					k = 1859775393;
				} else if (i>= 40 && i <= 59){
					f = (b & c) | (b & d) | (c & d);
					k = 2400959708;
				} else if (i >= 60 && i <= 79){
					f = b^c^d;
					k = 3395469782;
				}
				temp = ((a << 5) | (a >>> (32 - 5))) + f + e + k + w[i];
				e = d;
				d = c;
				c = (b << 30) | (b >>> (32 - 30));
				b = a;
				a = temp;
			}
			// Add this chunk's hash to result so far
			h0 = h0 + a;
			h1 = h1 + b;
			h2 = h2 + c;
			h3 = h3 + d;
			h4 = h4 + e;
		}
		
		// Produce the final hash value (big-endian)
		return hex(h0) + hex(h1) + hex(h2) + hex(h3) + hex(h4);
	}
});

Yep, mine is just an old code I wrote one year ago that I updated/cleaned/commented recently for the latest Mootools version.

But, yeah, his code does exactly the same job as mine ;)