var charBit = 8;

function sha2(str) {
	var k = new Array(
		0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
		0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
		0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
		0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
		0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
		0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
		0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
		0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
	);
	var w = Array(64);
	var a = 0x6A09E667;
	var b = 0xBB67AE85;
	var c = 0x3C6EF372;
	var d = 0xA54FF53A;
	var e = 0x510E527F;
	var f = 0x9B05688C;
	var g = 0x1F83D9AB;
	var h = 0x5BE0CD19;
	var x = strToBigEndianArray(str);
	var strBit = str.length * charBit;
	x[strBit >> 5] |= 0x80 << (24 - (strBit & 0x1f));
	x[((strBit + 64 >> 9) << 4) + 15] = strBit;
	var len = x.length;
	for (var i=0; i<len; i+=16)
	{
		var aa = a, bb = b, cc = c, dd = d;
		var ee = e, ff = f, gg = g, hh = h;
		var j = 0;
		for (; j<16; j++)
		{
			w[j] = x[i + j];

			var s0 = rotateRight(a, 2) ^ rotateRight(a, 13) ^ rotateRight(a, 22);
			var t0 = safeAdd(s0, (a & b) | (b & c) | (c & a));
			var s1 = rotateRight(e, 6) ^ rotateRight(e, 11) ^ rotateRight(e, 25);
			var t1 = safeAdd(safeAdd(safeAdd(safeAdd(h, s1), (e & f) | ((~e) & g)), k[j]), w[j]);
			h = g;
			g = f;
			f = e;
			e = safeAdd(d, t1);
			d = c;
			c = b;
			b = a;
			a = safeAdd(t0, t1);
		}
		for (; j<64; j++)
		{
			w[j] = safeAdd(safeAdd(safeAdd(w[j-16],
				rotateRight(w[j-15], 7) ^ rotateRight(w[j-15], 18) ^ (w[j-15] >>> 3)),
				w[j-7]),
				rotateRight(w[j-2], 17) ^ rotateRight(w[j-2], 19) ^ (w[j-2] >>> 10));
			var s0 = rotateRight(a, 2) ^ rotateRight(a, 13) ^ rotateRight(a, 22);
			var t0 = safeAdd(s0, (a & b) | (b & c) | (c & a));
			var s1 = rotateRight(e, 6) ^ rotateRight(e, 11) ^ rotateRight(e, 25);
			var t1 = safeAdd(safeAdd(safeAdd(safeAdd(h, s1), (e & f) | ((~e) & g)), k[j]), w[j]);
			h = g;
			g = f;
			f = e;
			e = safeAdd(d, t1);
			d = c;
			c = b;
			b = a;
			a = safeAdd(t0, t1);
		}
		a = safeAdd(a,aa);
		b = safeAdd(b,bb);
		c = safeAdd(c,cc);
		d = safeAdd(d,dd);
		e = safeAdd(e,ee);
		f = safeAdd(f,ff);
		g = safeAdd(g,gg);
		h = safeAdd(h,hh);
	}
	return bigEndianArrayToHex(Array(a, b, c, d, e, f, g, h));
}

function strToBigEndianArray(str) {
	var x = Array();
	var mask = (1 << charBit) - 1;
	var len = str.length;
	for (var i=0, j=0; j < len; i+=charBit) {
		x[i>>5] |= (str.charCodeAt(j++) & mask) << (32 - charBit - (i & 0x1f));
	}
	return x;
}

function bigEndianArrayToHex(ar) {
	var charHex = new Array('0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f');
	var str = "";
	var len = ar.length;
	for(var i = 0, tmp = len << 2; i < tmp; i++) {
		str += charHex[((ar[i>>2] >> (((3 - (i & 3)) << 3) + 4)) & 0xF)] +
		charHex[((ar[i>>2] >> ((3 - (i & 3)) << 3)) & 0xF)];
	}
	return str;
}

function rotateRight(val, n) {
	return ( val >>> n ) | (val << (32 - n));
}

function safeAdd(a, b) {
	var t = (a & 0xffff) + (b & 0xffff);
	return ((a >> 16) + (b >> 16) + (t >> 16) << 16) | (t & 0xffff);
}