xref: /plugin/securelogin/rsalib.js

// Copyright (c) 2005  Tom Wu
// All Rights Reserved.
// See "LICENSE" for details.

// Basic JavaScript BN library - subset useful for RSA encryption.

// Bits per digit
var dbits;

// JavaScript engine analysis
var canary = 0xdeadbeefcafe;
var j_lm = ((canary & 0xffffff) == 0xefcafe);

// (public) Constructor
function BigInteger(a, b, c) {
	if (a != null)
		if ("number" == typeof a)
			this.fromNumber(a, b, c);
		else if (b == null && "string" != typeof a)
			this.fromString(a, 256);
		else
			this.fromString(a, b);
}

// return new, unset BigInteger
function nbi() {
	return new BigInteger(null);
}

// am: Compute w_j += (x*this_i), propagate carries,
// c is initial carry, returns final carry.
// c < 3*dvalue, x < 2*dvalue, this_i < dvalue
// We need to select the fastest one that works in this environment.

// am1: use a single mult and divide to get the high bits,
// max digit bits should be 26 because
// max internal value = 2*dvalue^2-2*dvalue (< 2^53)
function am1(i, x, w, j, c, n) {
	while (--n >= 0) {
		var v = x * this[i++] + w[j] + c;
		c = Math.floor(v / 0x4000000);
		w[j++] = v & 0x3ffffff;
	}
	return c;
}
// am2 avoids a big mult-and-extract completely.
// Max digit bits should be <= 30 because we do bitwise ops
// on values up to 2*hdvalue^2-hdvalue-1 (< 2^31)
function am2(i, x, w, j, c, n) {
	var xl = x & 0x7fff, xh = x >> 15;
	while (--n >= 0) {
		var l = this[i] & 0x7fff;
		var h = this[i++] >> 15;
		var m = xh * l + h * xl;
		l = xl * l + ((m & 0x7fff) << 15) + w[j] + (c & 0x3fffffff);
		c = (l >>> 30) + (m >>> 15) + xh * h + (c >>> 30);
		w[j++] = l & 0x3fffffff;
	}
	return c;
}
// Alternately, set max digit bits to 28 since some
// browsers slow down when dealing with 32-bit numbers.
function am3(i, x, w, j, c, n) {
	var xl = x & 0x3fff, xh = x >> 14;
	while (--n >= 0) {
		var l = this[i] & 0x3fff;
		var h = this[i++] >> 14;
		var m = xh * l + h * xl;
		l = xl * l + ((m & 0x3fff) << 14) + w[j] + c;
		c = (l >> 28) + (m >> 14) + xh * h;
		w[j++] = l & 0xfffffff;
	}
	return c;
}
if (j_lm && (navigator.appName == "Microsoft Internet Explorer")) {
	BigInteger.prototype.am = am2;
	dbits = 30;
} else if (j_lm && (navigator.appName != "Netscape")) {
	BigInteger.prototype.am = am1;
	dbits = 26;
} else { // Mozilla/Netscape seems to prefer am3
	BigInteger.prototype.am = am3;
	dbits = 28;
}

BigInteger.prototype.DB = dbits;
BigInteger.prototype.DM = ((1 << dbits) - 1);
BigInteger.prototype.DV = (1 << dbits);

var BI_FP = 52;
BigInteger.prototype.FV = Math.pow(2, BI_FP);
BigInteger.prototype.F1 = BI_FP - dbits;
BigInteger.prototype.F2 = 2 * dbits - BI_FP;

// Digit conversions
var BI_RM = "0123456789abcdefghijklmnopqrstuvwxyz";
var BI_RC = new Array();
var rr, vv;
rr = "0".charCodeAt(0);
for (vv = 0; vv <= 9; ++vv)
	BI_RC[rr++] = vv;
rr = "a".charCodeAt(0);
for (vv = 10; vv < 36; ++vv)
	BI_RC[rr++] = vv;
rr = "A".charCodeAt(0);
for (vv = 10; vv < 36; ++vv)
	BI_RC[rr++] = vv;

function int2char(n) {
	return BI_RM.charAt(n);
}
function intAt(s, i) {
	var c = BI_RC[s.charCodeAt(i)];
	return (c == null) ? -1 : c;
}

// (protected) copy this to r
function bnpCopyTo(r) {
	for ( var i = this.t - 1; i >= 0; --i)
		r[i] = this[i];
	r.t = this.t;
	r.s = this.s;
}

// (protected) set from integer value x, -DV <= x < DV
function bnpFromInt(x) {
	this.t = 1;
	this.s = (x < 0) ? -1 : 0;
	if (x > 0)
		this[0] = x;
	else if (x < -1)
		this[0] = x + DV;
	else
		this.t = 0;
}

// return bigint initialized to value
function nbv(i) {
	var r = nbi();
	r.fromInt(i);
	return r;
}

// (protected) set from string and radix
function bnpFromString(s, b) {
	var k;
	if (b == 16)
		k = 4;
	else if (b == 8)
		k = 3;
	else if (b == 256)
		k = 8; // byte array
	else if (b == 2)
		k = 1;
	else if (b == 32)
		k = 5;
	else if (b == 4)
		k = 2;
	else {
		this.fromRadix(s, b);
		return;
	}
	this.t = 0;
	this.s = 0;
	var i = s.length, mi = false, sh = 0;
	while (--i >= 0) {
		var x = (k == 8) ? s[i] & 0xff : intAt(s, i);
		if (x < 0) {
			if (s.charAt(i) == "-")
				mi = true;
			continue;
		}
		mi = false;
		if (sh == 0)
			this[this.t++] = x;
		else if (sh + k > this.DB) {
			this[this.t - 1] |= (x & ((1 << (this.DB - sh)) - 1)) << sh;
			this[this.t++] = (x >> (this.DB - sh));
		} else
			this[this.t - 1] |= x << sh;
		sh += k;
		if (sh >= this.DB)
			sh -= this.DB;
	}
	if (k == 8 && (s[0] & 0x80) != 0) {
		this.s = -1;
		if (sh > 0)
			this[this.t - 1] |= ((1 << (this.DB - sh)) - 1) << sh;
	}
	this.clamp();
	if (mi)
		BigInteger.ZERO.subTo(this, this);
}

// (protected) clamp off excess high words
function bnpClamp() {
	var c = this.s & this.DM;
	while (this.t > 0 && this[this.t - 1] == c)
		--this.t;
}

// (public) return string representation in given radix
function bnToString(b) {
	if (this.s < 0)
		return "-" + this.negate().toString(b);
	var k;
	if (b == 16)
		k = 4;
	else if (b == 8)
		k = 3;
	else if (b == 2)
		k = 1;
	else if (b == 32)
		k = 5;
	else if (b == 4)
		k = 2;
	else
		return this.toRadix(b);
	var km = (1 << k) - 1, d, m = false, r = "", i = this.t;
	var p = this.DB - (i * this.DB) % k;
	if (i-- > 0) {
		if (p < this.DB && (d = this[i] >> p) > 0) {
			m = true;
			r = int2char(d);
		}
		while (i >= 0) {
			if (p < k) {
				d = (this[i] & ((1 << p) - 1)) << (k - p);
				d |= this[--i] >> (p += this.DB - k);
			} else {
				d = (this[i] >> (p -= k)) & km;
				if (p <= 0) {
					p += this.DB;
					--i;
				}
			}
			if (d > 0)
				m = true;
			if (m)
				r += int2char(d);
		}
	}
	return m ? r : "0";
}

// (public) -this
function bnNegate() {
	var r = nbi();
	BigInteger.ZERO.subTo(this, r);
	return r;
}

// (public) |this|
function bnAbs() {
	return (this.s < 0) ? this.negate() : this;
}

// (public) return + if this > a, - if this < a, 0 if equal
function bnCompareTo(a) {
	var r = this.s - a.s;
	if (r != 0)
		return r;
	var i = this.t;
	r = i - a.t;
	if (r != 0)
		return r;
	while (--i >= 0)
		if ((r = this[i] - a[i]) != 0)
			return r;
	return 0;
}

// returns bit length of the integer x
function nbits(x) {
	var r = 1, t;
	if ((t = x >>> 16) != 0) {
		x = t;
		r += 16;
	}
	if ((t = x >> 8) != 0) {
		x = t;
		r += 8;
	}
	if ((t = x >> 4) != 0) {
		x = t;
		r += 4;
	}
	if ((t = x >> 2) != 0) {
		x = t;
		r += 2;
	}
	if ((t = x >> 1) != 0) {
		x = t;
		r += 1;
	}
	return r;
}

// (public) return the number of bits in "this"
function bnBitLength() {
	if (this.t <= 0)
		return 0;
	return this.DB * (this.t - 1)
			+ nbits(this[this.t - 1] ^ (this.s & this.DM));
}

// (protected) r = this << n*DB
function bnpDLShiftTo(n, r) {
	var i;
	for (i = this.t - 1; i >= 0; --i)
		r[i + n] = this[i];
	for (i = n - 1; i >= 0; --i)
		r[i] = 0;
	r.t = this.t + n;
	r.s = this.s;
}

// (protected) r = this >> n*DB
function bnpDRShiftTo(n, r) {
	for ( var i = n; i < this.t; ++i)
		r[i - n] = this[i];
	r.t = Math.max(this.t - n, 0);
	r.s = this.s;
}

// (protected) r = this << n
function bnpLShiftTo(n, r) {
	var bs = n % this.DB;
	var cbs = this.DB - bs;
	var bm = (1 << cbs) - 1;
	var ds = Math.floor(n / this.DB), c = (this.s << bs) & this.DM, i;
	for (i = this.t - 1; i >= 0; --i) {
		r[i + ds + 1] = (this[i] >> cbs) | c;
		c = (this[i] & bm) << bs;
	}
	for (i = ds - 1; i >= 0; --i)
		r[i] = 0;
	r[ds] = c;
	r.t = this.t + ds + 1;
	r.s = this.s;
	r.clamp();
}

// (protected) r = this >> n
function bnpRShiftTo(n, r) {
	r.s = this.s;
	var ds = Math.floor(n / this.DB);
	if (ds >= this.t) {
		r.t = 0;
		return;
	}
	var bs = n % this.DB;
	var cbs = this.DB - bs;
	var bm = (1 << bs) - 1;
	r[0] = this[ds] >> bs;
	for ( var i = ds + 1; i < this.t; ++i) {
		r[i - ds - 1] |= (this[i] & bm) << cbs;
		r[i - ds] = this[i] >> bs;
	}
	if (bs > 0)
		r[this.t - ds - 1] |= (this.s & bm) << cbs;
	r.t = this.t - ds;
	r.clamp();
}

// (protected) r = this - a
function bnpSubTo(a, r) {
	var i = 0, c = 0, m = Math.min(a.t, this.t);
	while (i < m) {
		c += this[i] - a[i];
		r[i++] = c & this.DM;
		c >>= this.DB;
	}
	if (a.t < this.t) {
		c -= a.s;
		while (i < this.t) {
			c += this[i];
			r[i++] = c & this.DM;
			c >>= this.DB;
		}
		c += this.s;
	} else {
		c += this.s;
		while (i < a.t) {
			c -= a[i];
			r[i++] = c & this.DM;
			c >>= this.DB;
		}
		c -= a.s;
	}
	r.s = (c < 0) ? -1 : 0;
	if (c < -1)
		r[i++] = this.DV + c;
	else if (c > 0)
		r[i++] = c;
	r.t = i;
	r.clamp();
}

// (protected) r = this * a, r != this,a (HAC 14.12)
// "this" should be the larger one if appropriate.
function bnpMultiplyTo(a, r) {
	var x = this.abs(), y = a.abs();
	var i = x.t;
	r.t = i + y.t;
	while (--i >= 0)
		r[i] = 0;
	for (i = 0; i < y.t; ++i)
		r[i + x.t] = x.am(0, y[i], r, i, 0, x.t);
	r.s = 0;
	r.clamp();
	if (this.s != a.s)
		BigInteger.ZERO.subTo(r, r);
}

// (protected) r = this^2, r != this (HAC 14.16)
function bnpSquareTo(r) {
	var x = this.abs();
	var i = r.t = 2 * x.t;
	while (--i >= 0)
		r[i] = 0;
	for (i = 0; i < x.t - 1; ++i) {
		var c = x.am(i, x[i], r, 2 * i, 0, 1);
		if ((r[i + x.t] += x.am(i + 1, 2 * x[i], r, 2 * i + 1, c, x.t - i - 1)) >= x.DV) {
			r[i + x.t] -= x.DV;
			r[i + x.t + 1] = 1;
		}
	}
	if (r.t > 0)
		r[r.t - 1] += x.am(i, x[i], r, 2 * i, 0, 1);
	r.s = 0;
	r.clamp();
}

// (protected) divide this by m, quotient and remainder to q, r (HAC 14.20)
// r != q, this != m. q or r may be null.
function bnpDivRemTo(m, q, r) {
	var pm = m.abs();
	if (pm.t <= 0)
		return;
	var pt = this.abs();
	if (pt.t < pm.t) {
		if (q != null)
			q.fromInt(0);
		if (r != null)
			this.copyTo(r);
		return;
	}
	if (r == null)
		r = nbi();
	var y = nbi(), ts = this.s, ms = m.s;
	var nsh = this.DB - nbits(pm[pm.t - 1]); // normalize modulus
	if (nsh > 0) {
		pm.lShiftTo(nsh, y);
		pt.lShiftTo(nsh, r);
	} else {
		pm.copyTo(y);
		pt.copyTo(r);
	}
	var ys = y.t;
	var y0 = y[ys - 1];
	if (y0 == 0)
		return;
	var yt = y0 * (1 << this.F1) + ((ys > 1) ? y[ys - 2] >> this.F2 : 0);
	var d1 = this.FV / yt, d2 = (1 << this.F1) / yt, e = 1 << this.F2;
	var i = r.t, j = i - ys, t = (q == null) ? nbi() : q;
	y.dlShiftTo(j, t);
	if (r.compareTo(t) >= 0) {
		r[r.t++] = 1;
		r.subTo(t, r);
	}
	BigInteger.ONE.dlShiftTo(ys, t);
	t.subTo(y, y); // "negative" y so we can replace sub with am later
	while (y.t < ys)
		y[y.t++] = 0;
	while (--j >= 0) {
		// Estimate quotient digit
		var qd = (r[--i] == y0) ? this.DM : Math.floor(r[i] * d1
				+ (r[i - 1] + e) * d2);
		if ((r[i] += y.am(0, qd, r, j, 0, ys)) < qd) { // Try it out
			y.dlShiftTo(j, t);
			r.subTo(t, r);
			while (r[i] < --qd)
				r.subTo(t, r);
		}
	}
	if (q != null) {
		r.drShiftTo(ys, q);
		if (ts != ms)
			BigInteger.ZERO.subTo(q, q);
	}
	r.t = ys;
	r.clamp();
	if (nsh > 0)
		r.rShiftTo(nsh, r); // Denormalize remainder
	if (ts < 0)
		BigInteger.ZERO.subTo(r, r);
}

// (public) this mod a
function bnMod(a) {
	var r = nbi();
	this.abs().divRemTo(a, null, r);
	if (this.s < 0 && r.compareTo(BigInteger.ZERO) > 0)
		a.subTo(r, r);
	return r;
}

// Modular reduction using "classic" algorithm
function Classic(m) {
	this.m = m;
}
function cConvert(x) {
	if (x.s < 0 || x.compareTo(this.m) >= 0)
		return x.mod(this.m);
	else
		return x;
}
function cRevert(x) {
	return x;
}
function cReduce(x) {
	x.divRemTo(this.m, null, x);
}
function cMulTo(x, y, r) {
	x.multiplyTo(y, r);
	this.reduce(r);
}
function cSqrTo(x, r) {
	x.squareTo(r);
	this.reduce(r);
}

Classic.prototype.convert = cConvert;
Classic.prototype.revert = cRevert;
Classic.prototype.reduce = cReduce;
Classic.prototype.mulTo = cMulTo;
Classic.prototype.sqrTo = cSqrTo;

// (protected) return "-1/this % 2^DB"; useful for Mont. reduction
// justification:
// xy == 1 (mod m)
// xy = 1+km
// xy(2-xy) = (1+km)(1-km)
// x[y(2-xy)] = 1-k^2m^2
// x[y(2-xy)] == 1 (mod m^2)
// if y is 1/x mod m, then y(2-xy) is 1/x mod m^2
// should reduce x and y(2-xy) by m^2 at each step to keep size bounded.
// JS multiply "overflows" differently from C/C++, so care is needed here.
function bnpInvDigit() {
	if (this.t < 1)
		return 0;
	var x = this[0];
	if ((x & 1) == 0)
		return 0;
	var y = x & 3; // y == 1/x mod 2^2
	y = (y * (2 - (x & 0xf) * y)) & 0xf; // y == 1/x mod 2^4
	y = (y * (2 - (x & 0xff) * y)) & 0xff; // y == 1/x mod 2^8
	y = (y * (2 - (((x & 0xffff) * y) & 0xffff))) & 0xffff; // y == 1/x mod 2^16
	// last step - calculate inverse mod DV directly;
	// assumes 16 < DB <= 32 and assumes ability to handle 48-bit ints
	y = (y * (2 - x * y % this.DV)) % this.DV; // y == 1/x mod 2^dbits
	// we really want the negative inverse, and -DV < y < DV
	return (y > 0) ? this.DV - y : -y;
}

// Montgomery reduction
function Montgomery(m) {
	this.m = m;
	this.mp = m.invDigit();
	this.mpl = this.mp & 0x7fff;
	this.mph = this.mp >> 15;
	this.um = (1 << (m.DB - 15)) - 1;
	this.mt2 = 2 * m.t;
}

// xR mod m
function montConvert(x) {
	var r = nbi();
	x.abs().dlShiftTo(this.m.t, r);
	r.divRemTo(this.m, null, r);
	if (x.s < 0 && r.compareTo(BigInteger.ZERO) > 0)
		this.m.subTo(r, r);
	return r;
}

// x/R mod m
function montRevert(x) {
	var r = nbi();
	x.copyTo(r);
	this.reduce(r);
	return r;
}

// x = x/R mod m (HAC 14.32)
function montReduce(x) {
	while (x.t <= this.mt2)
		// pad x so am has enough room later
		x[x.t++] = 0;
	for ( var i = 0; i < this.m.t; ++i) {
		// faster way of calculating u0 = x[i]*mp mod DV
		var j = x[i] & 0x7fff;
		var u0 = (j * this.mpl + (((j * this.mph + (x[i] >> 15) * this.mpl) & this.um) << 15))
				& x.DM;
		// use am to combine the multiply-shift-add into one call
		j = i + this.m.t;
		x[j] += this.m.am(0, u0, x, i, 0, this.m.t);
		// propagate carry
		while (x[j] >= x.DV) {
			x[j] -= x.DV;
			x[++j]++;
		}
	}
	x.clamp();
	x.drShiftTo(this.m.t, x);
	if (x.compareTo(this.m) >= 0)
		x.subTo(this.m, x);
}

// r = "x^2/R mod m"; x != r
function montSqrTo(x, r) {
	x.squareTo(r);
	this.reduce(r);
}

// r = "xy/R mod m"; x,y != r
function montMulTo(x, y, r) {
	x.multiplyTo(y, r);
	this.reduce(r);
}

Montgomery.prototype.convert = montConvert;
Montgomery.prototype.revert = montRevert;
Montgomery.prototype.reduce = montReduce;
Montgomery.prototype.mulTo = montMulTo;
Montgomery.prototype.sqrTo = montSqrTo;

// (protected) true iff this is even
function bnpIsEven() {
	return ((this.t > 0) ? (this[0] & 1) : this.s) == 0;
}

// (protected) this^e, e < 2^32, doing sqr and mul with "r" (HAC 14.79)
function bnpExp(e, z) {
	if (e > 0xffffffff || e < 1)
		return BigInteger.ONE;
	var r = nbi(), r2 = nbi(), g = z.convert(this), i = nbits(e) - 1;
	g.copyTo(r);
	while (--i >= 0) {
		z.sqrTo(r, r2);
		if ((e & (1 << i)) > 0)
			z.mulTo(r2, g, r);
		else {
			var t = r;
			r = r2;
			r2 = t;
		}
	}
	return z.revert(r);
}

// (public) this^e % m, 0 <= e < 2^32
function bnModPowInt(e, m) {
	var z;
	if (e < 256 || m.isEven())
		z = new Classic(m);
	else
		z = new Montgomery(m);
	return this.exp(e, z);
}

// protected
BigInteger.prototype.copyTo = bnpCopyTo;
BigInteger.prototype.fromInt = bnpFromInt;
BigInteger.prototype.fromString = bnpFromString;
BigInteger.prototype.clamp = bnpClamp;
BigInteger.prototype.dlShiftTo = bnpDLShiftTo;
BigInteger.prototype.drShiftTo = bnpDRShiftTo;
BigInteger.prototype.lShiftTo = bnpLShiftTo;
BigInteger.prototype.rShiftTo = bnpRShiftTo;
BigInteger.prototype.subTo = bnpSubTo;
BigInteger.prototype.multiplyTo = bnpMultiplyTo;
BigInteger.prototype.squareTo = bnpSquareTo;
BigInteger.prototype.divRemTo = bnpDivRemTo;
BigInteger.prototype.invDigit = bnpInvDigit;
BigInteger.prototype.isEven = bnpIsEven;
BigInteger.prototype.exp = bnpExp;

// public
BigInteger.prototype.toString = bnToString;
BigInteger.prototype.negate = bnNegate;
BigInteger.prototype.abs = bnAbs;
BigInteger.prototype.compareTo = bnCompareTo;
BigInteger.prototype.bitLength = bnBitLength;
BigInteger.prototype.mod = bnMod;
BigInteger.prototype.modPowInt = bnModPowInt;

// "constants"
BigInteger.ZERO = nbv(0);
BigInteger.ONE = nbv(1);
// prng4.js - uses Arcfour as a PRNG

function Arcfour() {
	this.i = 0;
	this.j = 0;
	this.S = new Array();
}

// Initialize arcfour context from key, an array of ints, each from [0..255]
function ARC4init(key) {
	var i, j, t;
	for (i = 0; i < 256; ++i)
		this.S[i] = i;
	j = 0;
	for (i = 0; i < 256; ++i) {
		j = (j + this.S[i] + key[i % key.length]) & 255;
		t = this.S[i];
		this.S[i] = this.S[j];
		this.S[j] = t;
	}
	this.i = 0;
	this.j = 0;
}

function ARC4next() {
	var t;
	this.i = (this.i + 1) & 255;
	this.j = (this.j + this.S[this.i]) & 255;
	t = this.S[this.i];
	this.S[this.i] = this.S[this.j];
	this.S[this.j] = t;
	return this.S[(t + this.S[this.i]) & 255];
}

Arcfour.prototype.init = ARC4init;
Arcfour.prototype.next = ARC4next;

// Plug in your RNG constructor here
function prng_newstate() {
	return new Arcfour();
}

// Pool size must be a multiple of 4 and greater than 32.
// An array of bytes the size of the pool will be passed to init()
var rng_psize = 256;
// Random number generator - requires a PRNG backend, e.g. prng4.js

// For best results, put code like
// <body onClick='rng_seed_time();' onKeyPress='rng_seed_time();'>
// in your main HTML document.

var rng_state;
var rng_pool;
var rng_pptr;

// Mix in a 32-bit integer into the pool
function rng_seed_int(x) {
	rng_pool[rng_pptr++] ^= x & 255;
	rng_pool[rng_pptr++] ^= (x >> 8) & 255;
	rng_pool[rng_pptr++] ^= (x >> 16) & 255;
	rng_pool[rng_pptr++] ^= (x >> 24) & 255;
	if (rng_pptr >= rng_psize)
		rng_pptr -= rng_psize;
}

// Mix in the current time (w/milliseconds) into the pool
function rng_seed_time() {
	rng_seed_int(new Date().getTime());
}

// Initialize the pool with junk if needed.
if (rng_pool == null) {
	rng_pool = new Array();
	rng_pptr = 0;
	var t;
	if (navigator.appName == "Netscape" && navigator.appVersion < "5"
			&& window.crypto) {
		// Extract entropy (256 bits) from NS4 RNG if available
		var z = window.crypto.random(32);
		for (t = 0; t < z.length; ++t)
			rng_pool[rng_pptr++] = z.charCodeAt(t) & 255;
	}
	while (rng_pptr < rng_psize) { // extract some randomness from Math.random()
		t = Math.floor(65536 * Math.random());
		rng_pool[rng_pptr++] = t >>> 8;
		rng_pool[rng_pptr++] = t & 255;
	}
	rng_pptr = 0;
	rng_seed_time();
	// rng_seed_int(window.screenX);
	// rng_seed_int(window.screenY);
}

function rng_get_byte() {
	if (rng_state == null) {
		rng_seed_time();
		rng_state = prng_newstate();
		rng_state.init(rng_pool);
		for (rng_pptr = 0; rng_pptr < rng_pool.length; ++rng_pptr)
			rng_pool[rng_pptr] = 0;
		rng_pptr = 0;
		// rng_pool = null;
	}
	// TODO: allow reseeding after first request
	return rng_state.next();
}

function rng_get_bytes(ba) {
	var i;
	for (i = 0; i < ba.length; ++i)
		ba[i] = rng_get_byte();
}

function SecureRandom() {
}

SecureRandom.prototype.nextBytes = rng_get_bytes;
// Depends on jsbn.js and rng.js

// convert a (hex) string to a bignum object
function parseBigInt(str, r) {
	return new BigInteger(str, r);
}

function linebrk(s, n) {
	var ret = "";
	var i = 0;
	while (i + n < s.length) {
		ret += s.substring(i, i + n) + "\n";
		i += n;
	}
	return ret + s.substring(i, s.length);
}

function byte2Hex(b) {
	if (b < 0x10)
		return "0" + b.toString(16);
	else
		return b.toString(16);
}

// PKCS#1 (type 2, random) pad input string s to n bytes, and return a bigint
function pkcs1pad2(s, n) {
	if (n < s.length + 11) {
		alert("Message too long for RSA");
		return null;
	}
	var ba = new Array();
	var i = s.length - 1;
	while (i >= 0 && n > 0)
		ba[--n] = s.charCodeAt(i--);
	ba[--n] = 0;
	var rng = new SecureRandom();
	var x = new Array();
	while (n > 2) { // random non-zero pad
		x[0] = 0;
		while (x[0] == 0)
			rng.nextBytes(x);
		ba[--n] = x[0];
	}
	ba[--n] = 2;
	ba[--n] = 0;
	return new BigInteger(ba);
}

// "empty" RSA key constructor
function RSAKey() {
	this.n = null;
	this.e = 0;
	this.d = null;
	this.p = null;
	this.q = null;
	this.dmp1 = null;
	this.dmq1 = null;
	this.coeff = null;
}

// Set the public key fields N and e from hex strings
function RSASetPublic(N, E) {
	if (N != null && E != null && N.length > 0 && E.length > 0) {
		this.n = parseBigInt(N, 16);
		this.e = parseInt(E, 16);
	} else
		alert("Invalid RSA public key");
}

// Perform raw public operation on "x": return x^e (mod n)
function RSADoPublic(x) {
	return x.modPowInt(this.e, this.n);
}

// Return the PKCS#1 RSA encryption of "text" as an even-length hex string
function RSAEncrypt(text) {
	var m = pkcs1pad2(text, (this.n.bitLength() + 7) >> 3);
	if (m == null)
		return null;
	var c = this.doPublic(m);
	if (c == null)
		return null;
	var h = c.toString(16);
	if ((h.length & 1) == 0)
		return h;
	else
		return "0" + h;
}

// Return the PKCS#1 RSA encryption of "text" as a Base64-encoded string
// function RSAEncryptB64(text) {
// var h = this.encrypt(text);
// if(h) return hex2b64(h); else return null;
// }

// protected
RSAKey.prototype.doPublic = RSADoPublic;

// public
RSAKey.prototype.setPublic = RSASetPublic;
RSAKey.prototype.encrypt = RSAEncrypt;
// RSAKey.prototype.encrypt_b64 = RSAEncryptB64;
var b64map = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var b64pad = "=";

function hex2b64(h) {
	var i;
	var c;
	var ret = "";
	for (i = 0; i + 3 <= h.length; i += 3) {
		c = parseInt(h.substring(i, i + 3), 16);
		ret += b64map.charAt(c >> 6) + b64map.charAt(c & 63);
	}
	if (i + 1 == h.length) {
		c = parseInt(h.substring(i, i + 1), 16);
		ret += b64map.charAt(c << 2);
	} else if (i + 2 == h.length) {
		c = parseInt(h.substring(i, i + 2), 16);
		ret += b64map.charAt(c >> 2) + b64map.charAt((c & 3) << 4);
	}
	while ((ret.length & 3) > 0)
		ret += b64pad;
	return ret;
}

// convert a base64 string to hex
function b64tohex(s) {
	var ret = ""
	var i;
	var k = 0; // b64 state, 0-3
	var slop;
	for (i = 0; i < s.length; ++i) {
		if (s.charAt(i) == b64pad)
			break;
		v = b64map.indexOf(s.charAt(i));
		if (v < 0)
			continue;
		if (k == 0) {
			ret += int2char(v >> 2);
			slop = v & 3;
			k = 1;
		} else if (k == 1) {
			ret += int2char((slop << 2) | (v >> 4));
			slop = v & 0xf;
			k = 2;
		} else if (k == 2) {
			ret += int2char(slop);
			ret += int2char(v >> 2);
			slop = v & 3;
			k = 3;
		} else {
			ret += int2char((slop << 2) | (v >> 4));
			ret += int2char(v & 0xf);
			k = 0;
		}
	}
	if (k == 1)
		ret += int2char(slop << 2);
	return ret;
}

// convert a base64 string to a byte/number array
function b64toBA(s) {
	//piggyback on b64tohex for now, optimize later
	var h = b64tohex(s);
	var i;
	var a = new Array();
	for (i = 0; 2 * i < h.length; ++i) {
		a[i] = parseInt(h.substring(2 * i, 2 * i + 2), 16);
	}
	return a;
}