function sha1 ( str ) {	// Calculate the sha1 hash of a string
	// 
	// +   original by: Webtoolkit.info (http://www.webtoolkit.info/)
	// + namespaced by: Michael White (http://crestidg.com)

	var rotate_left = function(n,s) {
			var t4 = ( n<<s ) | (n>>>(32-s));
			return t4;
		};

	var lsb_hex = function(val) {
			var str="";
			var i;
			var vh;
			var vl;

			for( i=0; i<=6; i+=2 ) {
				vh = (val>>>(i*4+4))&0x0f;
				vl = (val>>>(i*4))&0x0f;
				str += vh.toString(16) + vl.toString(16);
			}
			return str;
		};

	var cvt_hex = function(val) {
			var str="";
			var i;
			var v;

			for( i=7; i>=0; i-- ) {
				v = (val>>>(i*4))&0x0f;
				str += v.toString(16);
			}
			return str;
		};

	var blockstart;
	var i, j;
	var W = new Array(80);
	var H0 = 0x67452301;
	var H1 = 0xEFCDAB89;
	var H2 = 0x98BADCFE;
	var H3 = 0x10325476;
	var H4 = 0xC3D2E1F0;
	var A, B, C, D, E;
	var temp;

	str = this.utf8_encode(str);
	var str_len = str.length;

	var word_array = new Array();
	for( i=0; i<str_len-3; i+=4 ) {
		j = str.charCodeAt(i)<<24 | str.charCodeAt(i+1)<<16 |
		str.charCodeAt(i+2)<<8 | str.charCodeAt(i+3);
		word_array.push( j );
	}

	switch( str_len % 4 ) {
		case 0:
			i = 0x080000000;
		break;
		case 1:
			i = str.charCodeAt(str_len-1)<<24 | 0x0800000;
		break;
		case 2:
			i = str.charCodeAt(str_len-2)<<24 | str.charCodeAt(str_len-1)<<16 | 0x08000;
		break;
		case 3:
			i = str.charCodeAt(str_len-3)<<24 | str.charCodeAt(str_len-2)<<16 | str.charCodeAt(str_len-1)<<8	| 0x80;
		break;
	}

	word_array.push( i );

	while( (word_array.length % 16) != 14 ) word_array.push( 0 );

	word_array.push( str_len>>>29 );
	word_array.push( (str_len<<3)&0x0ffffffff );

	for ( blockstart=0; blockstart<word_array.length; blockstart+=16 ) {
		for( i=0; i<16; i++ ) W[i] = word_array[blockstart+i];
		for( i=16; i<=79; i++ ) W[i] = rotate_left(W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16], 1);

		A = H0;
		B = H1;
		C = H2;
		D = H3;
		E = H4;

		for( i= 0; i<=19; i++ ) {
			temp = (rotate_left(A,5) + ((B&C) | (~B&D)) + E + W[i] + 0x5A827999) & 0x0ffffffff;
			E = D;
			D = C;
			C = rotate_left(B,30);
			B = A;
			A = temp;
		}

		for( i=20; i<=39; i++ ) {
			temp = (rotate_left(A,5) + (B ^ C ^ D) + E + W[i] + 0x6ED9EBA1) & 0x0ffffffff;
			E = D;
			D = C;
			C = rotate_left(B,30);
			B = A;
			A = temp;
		}

		for( i=40; i<=59; i++ ) {
			temp = (rotate_left(A,5) + ((B&C) | (B&D) | (C&D)) + E + W[i] + 0x8F1BBCDC) & 0x0ffffffff;
			E = D;
			D = C;
			C = rotate_left(B,30);
			B = A;
			A = temp;
		}

		for( i=60; i<=79; i++ ) {
			temp = (rotate_left(A,5) + (B ^ C ^ D) + E + W[i] + 0xCA62C1D6) & 0x0ffffffff;
			E = D;
			D = C;
			C = rotate_left(B,30);
			B = A;
			A = temp;
		}

		H0 = (H0 + A) & 0x0ffffffff;
		H1 = (H1 + B) & 0x0ffffffff;
		H2 = (H2 + C) & 0x0ffffffff;
		H3 = (H3 + D) & 0x0ffffffff;
		H4 = (H4 + E) & 0x0ffffffff;
	}

	var temp = cvt_hex(H0) + cvt_hex(H1) + cvt_hex(H2) + cvt_hex(H3) + cvt_hex(H4);
	return temp.toLowerCase();
}