index.js

(function() {
  // 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;
  }
  var inBrowser = typeof navigator !== 'undefined';
  if (inBrowser && j_lm && navigator.appName == 'Microsoft Internet Explorer') {
    BigInteger.prototype.am = am2;
    dbits = 30;
  } else if (inBrowser && 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 + this.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) {
    // Auto-detect string notations
    if (!b && s.length >= 2 && s[0] === '0') {
      var isDetected = true;
      switch (s[1]) {
        case 'x': // Hexadecimal notation
          b = 16;
          break;
        case 'b': // Binary notation
          b = 2;
          break;
        case 'o': // Octal notation
          b = 8;
          break;
        default:
          isDetected = false;
      }

      // Remove the notation string if any has been detected
      if (isDetected) {
        s = s.substr(2);
      }
    }

    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 this.s < 0 ? -r : 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);

  // Copyright (c) 2005-2009  Tom Wu
  // All Rights Reserved.
  // See "LICENSE" for details.

  // Extended JavaScript BN functions, required for RSA private ops.

  // Version 1.1: new BigInteger("0", 10) returns "proper" zero
  // Version 1.2: square() API, isProbablePrime fix

  // (public)
  function bnClone() {
    var r = nbi();
    this.copyTo(r);
    return r;
  }

  // (public) return value as integer
  function bnIntValue() {
    if (this.s < 0) {
      if (this.t == 1) return this[0] - this.DV;
      else if (this.t == 0) return -1;
    } else if (this.t == 1) return this[0];
    else if (this.t == 0) return 0;
    // assumes 16 < DB < 32
    return ((this[1] & ((1 << (32 - this.DB)) - 1)) << this.DB) | this[0];
  }

  // (public) return value as byte
  function bnByteValue() {
    return this.t == 0 ? this.s : (this[0] << 24) >> 24;
  }

  // (public) return value as short (assumes DB>=16)
  function bnShortValue() {
    return this.t == 0 ? this.s : (this[0] << 16) >> 16;
  }

  // (protected) return x s.t. r^x < DV
  function bnpChunkSize(r) {
    return Math.floor((Math.LN2 * this.DB) / Math.log(r));
  }

  // (public) 0 if this == 0, 1 if this > 0
  function bnSigNum() {
    if (this.s < 0) return -1;
    else if (this.t <= 0 || (this.t == 1 && this[0] <= 0)) return 0;
    else return 1;
  }

  // (protected) convert to radix string
  function bnpToRadix(b) {
    if (b == null) b = 10;
    if (this.signum() == 0 || b < 2 || b > 36) return '0';
    var cs = this.chunkSize(b);
    var a = Math.pow(b, cs);
    var d = nbv(a),
      y = nbi(),
      z = nbi(),
      r = '';
    this.divRemTo(d, y, z);
    while (y.signum() > 0) {
      r = (a + z.intValue()).toString(b).substr(1) + r;
      y.divRemTo(d, y, z);
    }
    return z.intValue().toString(b) + r;
  }

  // (protected) convert from radix string
  function bnpFromRadix(s, b) {
    this.fromInt(0);
    if (b == null) b = 10;
    var cs = this.chunkSize(b);
    var d = Math.pow(b, cs),
      mi = false,
      j = 0,
      w = 0;
    for (var i = 0; i < s.length; ++i) {
      var x = intAt(s, i);
      if (x < 0) {
        if (s.charAt(i) == '-' && this.signum() == 0) mi = true;
        continue;
      }
      w = b * w + x;
      if (++j >= cs) {
        this.dMultiply(d);
        this.dAddOffset(w, 0);
        j = 0;
        w = 0;
      }
    }
    if (j > 0) {
      this.dMultiply(Math.pow(b, j));
      this.dAddOffset(w, 0);
    }
    if (mi) BigInteger.ZERO.subTo(this, this);
  }

  // (protected) alternate constructor
  function bnpFromNumber(a, b, c) {
    if ('number' == typeof b) {
      // new BigInteger(int,int,RNG)
      if (a < 2) this.fromInt(1);
      else {
        this.fromNumber(a, c);
        if (!this.testBit(a - 1))
          // force MSB set
          this.bitwiseTo(BigInteger.ONE.shiftLeft(a - 1), op_or, this);
        if (this.isEven()) this.dAddOffset(1, 0); // force odd
        while (!this.isProbablePrime(b)) {
          this.dAddOffset(2, 0);
          if (this.bitLength() > a)
            this.subTo(BigInteger.ONE.shiftLeft(a - 1), this);
        }
      }
    } else {
      // new BigInteger(int,RNG)
      var x = new Array(),
        t = a & 7;
      x.length = (a >> 3) + 1;
      b.nextBytes(x);
      if (t > 0) x[0] &= (1 << t) - 1;
      else x[0] = 0;
      this.fromString(x, 256);
    }
  }

  // (public) convert to bigendian byte array
  function bnToByteArray() {
    var i = this.t,
      r = new Array();
    r[0] = this.s;
    var p = this.DB - ((i * this.DB) % 8),
      d,
      k = 0;
    if (i-- > 0) {
      if (p < this.DB && (d = this[i] >> p) != (this.s & this.DM) >> p)
        r[k++] = d | (this.s << (this.DB - p));
      while (i >= 0) {
        if (p < 8) {
          d = (this[i] & ((1 << p) - 1)) << (8 - p);
          d |= this[--i] >> (p += this.DB - 8);
        } else {
          d = (this[i] >> (p -= 8)) & 0xff;
          if (p <= 0) {
            p += this.DB;
            --i;
          }
        }
        if ((d & 0x80) != 0) d |= -256;
        if (k == 0 && (this.s & 0x80) != (d & 0x80)) ++k;
        if (k > 0 || d != this.s) r[k++] = d;
      }
    }
    return r;
  }

  function bnEquals(a) {
    return this.compareTo(a) == 0;
  }
  function bnMin(a) {
    return this.compareTo(a) < 0 ? this : a;
  }
  function bnMax(a) {
    return this.compareTo(a) > 0 ? this : a;
  }

  // (protected) r = this op a (bitwise)
  function bnpBitwiseTo(a, op, r) {
    var i,
      f,
      m = Math.min(a.t, this.t);
    for (i = 0; i < m; ++i) r[i] = op(this[i], a[i]);
    if (a.t < this.t) {
      f = a.s & this.DM;
      for (i = m; i < this.t; ++i) r[i] = op(this[i], f);
      r.t = this.t;
    } else {
      f = this.s & this.DM;
      for (i = m; i < a.t; ++i) r[i] = op(f, a[i]);
      r.t = a.t;
    }
    r.s = op(this.s, a.s);
    r.clamp();
  }

  // (public) this & a
  function op_and(x, y) {
    return x & y;
  }
  function bnAnd(a) {
    var r = nbi();
    this.bitwiseTo(a, op_and, r);
    return r;
  }

  // (public) this | a
  function op_or(x, y) {
    return x | y;
  }
  function bnOr(a) {
    var r = nbi();
    this.bitwiseTo(a, op_or, r);
    return r;
  }

  // (public) this ^ a
  function op_xor(x, y) {
    return x ^ y;
  }
  function bnXor(a) {
    var r = nbi();
    this.bitwiseTo(a, op_xor, r);
    return r;
  }

  // (public) this & ~a
  function op_andnot(x, y) {
    return x & ~y;
  }
  function bnAndNot(a) {
    var r = nbi();
    this.bitwiseTo(a, op_andnot, r);
    return r;
  }

  // (public) ~this
  function bnNot() {
    var r = nbi();
    for (var i = 0; i < this.t; ++i) r[i] = this.DM & ~this[i];
    r.t = this.t;
    r.s = ~this.s;
    return r;
  }

  // (public) this << n
  function bnShiftLeft(n) {
    var r = nbi();
    if (n < 0) this.rShiftTo(-n, r);
    else this.lShiftTo(n, r);
    return r;
  }

  // (public) this >> n
  function bnShiftRight(n) {
    var r = nbi();
    if (n < 0) this.lShiftTo(-n, r);
    else this.rShiftTo(n, r);
    return r;
  }

  // return index of lowest 1-bit in x, x < 2^31
  function lbit(x) {
    if (x == 0) return -1;
    var r = 0;
    if ((x & 0xffff) == 0) {
      x >>= 16;
      r += 16;
    }
    if ((x & 0xff) == 0) {
      x >>= 8;
      r += 8;
    }
    if ((x & 0xf) == 0) {
      x >>= 4;
      r += 4;
    }
    if ((x & 3) == 0) {
      x >>= 2;
      r += 2;
    }
    if ((x & 1) == 0) ++r;
    return r;
  }

  // (public) returns index of lowest 1-bit (or -1 if none)
  function bnGetLowestSetBit() {
    for (var i = 0; i < this.t; ++i)
      if (this[i] != 0) return i * this.DB + lbit(this[i]);
    if (this.s < 0) return this.t * this.DB;
    return -1;
  }

  // return number of 1 bits in x
  function cbit(x) {
    var r = 0;
    while (x != 0) {
      x &= x - 1;
      ++r;
    }
    return r;
  }

  // (public) return number of set bits
  function bnBitCount() {
    var r = 0,
      x = this.s & this.DM;
    for (var i = 0; i < this.t; ++i) r += cbit(this[i] ^ x);
    return r;
  }

  // (public) true iff nth bit is set
  function bnTestBit(n) {
    var j = Math.floor(n / this.DB);
    if (j >= this.t) return this.s != 0;
    return (this[j] & (1 << n % this.DB)) != 0;
  }

  // (protected) this op (1<<n)
  function bnpChangeBit(n, op) {
    var r = BigInteger.ONE.shiftLeft(n);
    this.bitwiseTo(r, op, r);
    return r;
  }

  // (public) this | (1<<n)
  function bnSetBit(n) {
    return this.changeBit(n, op_or);
  }

  // (public) this & ~(1<<n)
  function bnClearBit(n) {
    return this.changeBit(n, op_andnot);
  }

  // (public) this ^ (1<<n)
  function bnFlipBit(n) {
    return this.changeBit(n, op_xor);
  }

  // (protected) r = this + a
  function bnpAddTo(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 > 0) r[i++] = c;
    else if (c < -1) r[i++] = this.DV + c;
    r.t = i;
    r.clamp();
  }

  // (public) this + a
  function bnAdd(a) {
    var r = nbi();
    this.addTo(a, r);
    return r;
  }

  // (public) this - a
  function bnSubtract(a) {
    var r = nbi();
    this.subTo(a, r);
    return r;
  }

  // (public) this * a
  function bnMultiply(a) {
    var r = nbi();
    this.multiplyTo(a, r);
    return r;
  }

  // (public) this^2
  function bnSquare() {
    var r = nbi();
    this.squareTo(r);
    return r;
  }

  // (public) this / a
  function bnDivide(a) {
    var r = nbi();
    this.divRemTo(a, r, null);
    return r;
  }

  // (public) this % a
  function bnRemainder(a) {
    var r = nbi();
    this.divRemTo(a, null, r);
    return r;
  }

  // (public) [this/a,this%a]
  function bnDivideAndRemainder(a) {
    var q = nbi(),
      r = nbi();
    this.divRemTo(a, q, r);
    return new Array(q, r);
  }

  // (protected) this *= n, this >= 0, 1 < n < DV
  function bnpDMultiply(n) {
    this[this.t] = this.am(0, n - 1, this, 0, 0, this.t);
    ++this.t;
    this.clamp();
  }

  // (protected) this += n << w words, this >= 0
  function bnpDAddOffset(n, w) {
    if (n == 0) return;
    while (this.t <= w) this[this.t++] = 0;
    this[w] += n;
    while (this[w] >= this.DV) {
      this[w] -= this.DV;
      if (++w >= this.t) this[this.t++] = 0;
      ++this[w];
    }
  }

  // A "null" reducer
  function NullExp() {}
  function nNop(x) {
    return x;
  }
  function nMulTo(x, y, r) {
    x.multiplyTo(y, r);
  }
  function nSqrTo(x, r) {
    x.squareTo(r);
  }

  NullExp.prototype.convert = nNop;
  NullExp.prototype.revert = nNop;
  NullExp.prototype.mulTo = nMulTo;
  NullExp.prototype.sqrTo = nSqrTo;

  // (public) this^e
  function bnPow(e) {
    return this.exp(e, new NullExp());
  }

  // (protected) r = lower n words of "this * a", a.t <= n
  // "this" should be the larger one if appropriate.
  function bnpMultiplyLowerTo(a, n, r) {
    var i = Math.min(this.t + a.t, n);
    r.s = 0; // assumes a,this >= 0
    r.t = i;
    while (i > 0) r[--i] = 0;
    var j;
    for (j = r.t - this.t; i < j; ++i)
      r[i + this.t] = this.am(0, a[i], r, i, 0, this.t);
    for (j = Math.min(a.t, n); i < j; ++i) this.am(0, a[i], r, i, 0, n - i);
    r.clamp();
  }

  // (protected) r = "this * a" without lower n words, n > 0
  // "this" should be the larger one if appropriate.
  function bnpMultiplyUpperTo(a, n, r) {
    --n;
    var i = (r.t = this.t + a.t - n);
    r.s = 0; // assumes a,this >= 0
    while (--i >= 0) r[i] = 0;
    for (i = Math.max(n - this.t, 0); i < a.t; ++i)
      r[this.t + i - n] = this.am(n - i, a[i], r, 0, 0, this.t + i - n);
    r.clamp();
    r.drShiftTo(1, r);
  }

  // Barrett modular reduction
  function Barrett(m) {
    // setup Barrett
    this.r2 = nbi();
    this.q3 = nbi();
    BigInteger.ONE.dlShiftTo(2 * m.t, this.r2);
    this.mu = this.r2.divide(m);
    this.m = m;
  }

  function barrettConvert(x) {
    if (x.s < 0 || x.t > 2 * this.m.t) return x.mod(this.m);
    else if (x.compareTo(this.m) < 0) return x;
    else {
      var r = nbi();
      x.copyTo(r);
      this.reduce(r);
      return r;
    }
  }

  function barrettRevert(x) {
    return x;
  }

  // x = x mod m (HAC 14.42)
  function barrettReduce(x) {
    x.drShiftTo(this.m.t - 1, this.r2);
    if (x.t > this.m.t + 1) {
      x.t = this.m.t + 1;
      x.clamp();
    }
    this.mu.multiplyUpperTo(this.r2, this.m.t + 1, this.q3);
    this.m.multiplyLowerTo(this.q3, this.m.t + 1, this.r2);
    while (x.compareTo(this.r2) < 0) x.dAddOffset(1, this.m.t + 1);
    x.subTo(this.r2, x);
    while (x.compareTo(this.m) >= 0) x.subTo(this.m, x);
  }

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

  // r = x*y mod m; x,y != r
  function barrettMulTo(x, y, r) {
    x.multiplyTo(y, r);
    this.reduce(r);
  }

  Barrett.prototype.convert = barrettConvert;
  Barrett.prototype.revert = barrettRevert;
  Barrett.prototype.reduce = barrettReduce;
  Barrett.prototype.mulTo = barrettMulTo;
  Barrett.prototype.sqrTo = barrettSqrTo;

  // (public) this^e % m (HAC 14.85)
  function bnModPow(e, m) {
    var i = e.bitLength(),
      k,
      r = nbv(1),
      z;
    if (i <= 0) return r;
    else if (i < 18) k = 1;
    else if (i < 48) k = 3;
    else if (i < 144) k = 4;
    else if (i < 768) k = 5;
    else k = 6;
    if (i < 8) z = new Classic(m);
    else if (m.isEven()) z = new Barrett(m);
    else z = new Montgomery(m);

    // precomputation
    var g = new Array(),
      n = 3,
      k1 = k - 1,
      km = (1 << k) - 1;
    g[1] = z.convert(this);
    if (k > 1) {
      var g2 = nbi();
      z.sqrTo(g[1], g2);
      while (n <= km) {
        g[n] = nbi();
        z.mulTo(g2, g[n - 2], g[n]);
        n += 2;
      }
    }

    var j = e.t - 1,
      w,
      is1 = true,
      r2 = nbi(),
      t;
    i = nbits(e[j]) - 1;
    while (j >= 0) {
      if (i >= k1) w = (e[j] >> (i - k1)) & km;
      else {
        w = (e[j] & ((1 << (i + 1)) - 1)) << (k1 - i);
        if (j > 0) w |= e[j - 1] >> (this.DB + i - k1);
      }

      n = k;
      while ((w & 1) == 0) {
        w >>= 1;
        --n;
      }
      if ((i -= n) < 0) {
        i += this.DB;
        --j;
      }
      if (is1) {
        // ret == 1, don't bother squaring or multiplying it
        g[w].copyTo(r);
        is1 = false;
      } else {
        while (n > 1) {
          z.sqrTo(r, r2);
          z.sqrTo(r2, r);
          n -= 2;
        }
        if (n > 0) z.sqrTo(r, r2);
        else {
          t = r;
          r = r2;
          r2 = t;
        }
        z.mulTo(r2, g[w], r);
      }

      while (j >= 0 && (e[j] & (1 << i)) == 0) {
        z.sqrTo(r, r2);
        t = r;
        r = r2;
        r2 = t;
        if (--i < 0) {
          i = this.DB - 1;
          --j;
        }
      }
    }
    return z.revert(r);
  }

  // (public) gcd(this,a) (HAC 14.54)
  function bnGCD(a) {
    var x = this.s < 0 ? this.negate() : this.clone();
    var y = a.s < 0 ? a.negate() : a.clone();
    if (x.compareTo(y) < 0) {
      var t = x;
      x = y;
      y = t;
    }
    var i = x.getLowestSetBit(),
      g = y.getLowestSetBit();
    if (g < 0) return x;
    if (i < g) g = i;
    if (g > 0) {
      x.rShiftTo(g, x);
      y.rShiftTo(g, y);
    }
    while (x.signum() > 0) {
      if ((i = x.getLowestSetBit()) > 0) x.rShiftTo(i, x);
      if ((i = y.getLowestSetBit()) > 0) y.rShiftTo(i, y);
      if (x.compareTo(y) >= 0) {
        x.subTo(y, x);
        x.rShiftTo(1, x);
      } else {
        y.subTo(x, y);
        y.rShiftTo(1, y);
      }
    }
    if (g > 0) y.lShiftTo(g, y);
    return y;
  }

  // (protected) this % n, n < 2^26
  function bnpModInt(n) {
    if (n <= 0) return 0;
    var d = this.DV % n,
      r = this.s < 0 ? n - 1 : 0;
    if (this.t > 0)
      if (d == 0) r = this[0] % n;
      else for (var i = this.t - 1; i >= 0; --i) r = (d * r + this[i]) % n;
    return r;
  }

  // (public) 1/this % m (HAC 14.61)
  function bnModInverse(m) {
    var ac = m.isEven();
    if ((this.isEven() && ac) || m.signum() == 0) return BigInteger.ZERO;
    var u = m.clone(),
      v = this.clone();
    var a = nbv(1),
      b = nbv(0),
      c = nbv(0),
      d = nbv(1);
    while (u.signum() != 0) {
      while (u.isEven()) {
        u.rShiftTo(1, u);
        if (ac) {
          if (!a.isEven() || !b.isEven()) {
            a.addTo(this, a);
            b.subTo(m, b);
          }
          a.rShiftTo(1, a);
        } else if (!b.isEven()) b.subTo(m, b);
        b.rShiftTo(1, b);
      }
      while (v.isEven()) {
        v.rShiftTo(1, v);
        if (ac) {
          if (!c.isEven() || !d.isEven()) {
            c.addTo(this, c);
            d.subTo(m, d);
          }
          c.rShiftTo(1, c);
        } else if (!d.isEven()) d.subTo(m, d);
        d.rShiftTo(1, d);
      }
      if (u.compareTo(v) >= 0) {
        u.subTo(v, u);
        if (ac) a.subTo(c, a);
        b.subTo(d, b);
      } else {
        v.subTo(u, v);
        if (ac) c.subTo(a, c);
        d.subTo(b, d);
      }
    }
    if (v.compareTo(BigInteger.ONE) != 0) return BigInteger.ZERO;
    if (d.compareTo(m) >= 0) return d.subtract(m);
    if (d.signum() < 0) d.addTo(m, d);
    else return d;
    if (d.signum() < 0) return d.add(m);
    else return d;
  }

  var lowprimes = [
    2,
    3,
    5,
    7,
    11,
    13,
    17,
    19,
    23,
    29,
    31,
    37,
    41,
    43,
    47,
    53,
    59,
    61,
    67,
    71,
    73,
    79,
    83,
    89,
    97,
    101,
    103,
    107,
    109,
    113,
    127,
    131,
    137,
    139,
    149,
    151,
    157,
    163,
    167,
    173,
    179,
    181,
    191,
    193,
    197,
    199,
    211,
    223,
    227,
    229,
    233,
    239,
    241,
    251,
    257,
    263,
    269,
    271,
    277,
    281,
    283,
    293,
    307,
    311,
    313,
    317,
    331,
    337,
    347,
    349,
    353,
    359,
    367,
    373,
    379,
    383,
    389,
    397,
    401,
    409,
    419,
    421,
    431,
    433,
    439,
    443,
    449,
    457,
    461,
    463,
    467,
    479,
    487,
    491,
    499,
    503,
    509,
    521,
    523,
    541,
    547,
    557,
    563,
    569,
    571,
    577,
    587,
    593,
    599,
    601,
    607,
    613,
    617,
    619,
    631,
    641,
    643,
    647,
    653,
    659,
    661,
    673,
    677,
    683,
    691,
    701,
    709,
    719,
    727,
    733,
    739,
    743,
    751,
    757,
    761,
    769,
    773,
    787,
    797,
    809,
    811,
    821,
    823,
    827,
    829,
    839,
    853,
    857,
    859,
    863,
    877,
    881,
    883,
    887,
    907,
    911,
    919,
    929,
    937,
    941,
    947,
    953,
    967,
    971,
    977,
    983,
    991,
    997,
  ];
  var lplim = (1 << 26) / lowprimes[lowprimes.length - 1];

  // (public) test primality with certainty >= 1-.5^t
  function bnIsProbablePrime(t) {
    var i,
      x = this.abs();
    if (x.t == 1 && x[0] <= lowprimes[lowprimes.length - 1]) {
      for (i = 0; i < lowprimes.length; ++i)
        if (x[0] == lowprimes[i]) return true;
      return false;
    }
    if (x.isEven()) return false;
    i = 1;
    while (i < lowprimes.length) {
      var m = lowprimes[i],
        j = i + 1;
      while (j < lowprimes.length && m < lplim) m *= lowprimes[j++];
      m = x.modInt(m);
      while (i < j) if (m % lowprimes[i++] == 0) return false;
    }
    return x.millerRabin(t);
  }

  // (protected) true if probably prime (HAC 4.24, Miller-Rabin)
  function bnpMillerRabin(t) {
    var n1 = this.subtract(BigInteger.ONE);
    var k = n1.getLowestSetBit();
    if (k <= 0) return false;
    var r = n1.shiftRight(k);
    t = (t + 1) >> 1;
    if (t > lowprimes.length) t = lowprimes.length;
    var a = nbi();
    for (var i = 0; i < t; ++i) {
      //Pick bases at random, instead of starting at 2
      a.fromInt(lowprimes[Math.floor(Math.random() * lowprimes.length)]);
      var y = a.modPow(r, this);
      if (y.compareTo(BigInteger.ONE) != 0 && y.compareTo(n1) != 0) {
        var j = 1;
        while (j++ < k && y.compareTo(n1) != 0) {
          y = y.modPowInt(2, this);
          if (y.compareTo(BigInteger.ONE) == 0) return false;
        }
        if (y.compareTo(n1) != 0) return false;
      }
    }
    return true;
  }

  // protected
  BigInteger.prototype.chunkSize = bnpChunkSize;
  BigInteger.prototype.toRadix = bnpToRadix;
  BigInteger.prototype.fromRadix = bnpFromRadix;
  BigInteger.prototype.fromNumber = bnpFromNumber;
  BigInteger.prototype.bitwiseTo = bnpBitwiseTo;
  BigInteger.prototype.changeBit = bnpChangeBit;
  BigInteger.prototype.addTo = bnpAddTo;
  BigInteger.prototype.dMultiply = bnpDMultiply;
  BigInteger.prototype.dAddOffset = bnpDAddOffset;
  BigInteger.prototype.multiplyLowerTo = bnpMultiplyLowerTo;
  BigInteger.prototype.multiplyUpperTo = bnpMultiplyUpperTo;
  BigInteger.prototype.modInt = bnpModInt;
  BigInteger.prototype.millerRabin = bnpMillerRabin;

  // public
  BigInteger.prototype.clone = bnClone;
  BigInteger.prototype.intValue = bnIntValue;
  BigInteger.prototype.byteValue = bnByteValue;
  BigInteger.prototype.shortValue = bnShortValue;
  BigInteger.prototype.signum = bnSigNum;
  BigInteger.prototype.toByteArray = bnToByteArray;
  BigInteger.prototype.equals = bnEquals;
  BigInteger.prototype.min = bnMin;
  BigInteger.prototype.max = bnMax;
  BigInteger.prototype.and = bnAnd;
  BigInteger.prototype.or = bnOr;
  BigInteger.prototype.xor = bnXor;
  BigInteger.prototype.andNot = bnAndNot;
  BigInteger.prototype.not = bnNot;
  BigInteger.prototype.shiftLeft = bnShiftLeft;
  BigInteger.prototype.shiftRight = bnShiftRight;
  BigInteger.prototype.getLowestSetBit = bnGetLowestSetBit;
  BigInteger.prototype.bitCount = bnBitCount;
  BigInteger.prototype.testBit = bnTestBit;
  BigInteger.prototype.setBit = bnSetBit;
  BigInteger.prototype.clearBit = bnClearBit;
  BigInteger.prototype.flipBit = bnFlipBit;
  BigInteger.prototype.add = bnAdd;
  BigInteger.prototype.subtract = bnSubtract;
  BigInteger.prototype.multiply = bnMultiply;
  BigInteger.prototype.divide = bnDivide;
  BigInteger.prototype.remainder = bnRemainder;
  BigInteger.prototype.divideAndRemainder = bnDivideAndRemainder;
  BigInteger.prototype.modPow = bnModPow;
  BigInteger.prototype.modInverse = bnModInverse;
  BigInteger.prototype.pow = bnPow;
  BigInteger.prototype.gcd = bnGCD;
  BigInteger.prototype.isProbablePrime = bnIsProbablePrime;

  // JSBN-specific extension
  BigInteger.prototype.square = bnSquare;

  // Expose the Barrett function
  BigInteger.prototype.Barrett = Barrett;

  // BigInteger interfaces not implemented in jsbn:

  // BigInteger(int signum, byte[] magnitude)
  // double doubleValue()
  // float floatValue()
  // int hashCode()
  // long longValue()
  // static BigInteger valueOf(long val)

  // 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 (typeof window !== 'undefined' && window.crypto) {
      if (window.crypto.getRandomValues) {
        // Use webcrypto if available
        var ua = new Uint8Array(32);
        window.crypto.getRandomValues(ua);
        for (t = 0; t < 32; ++t) rng_pool[rng_pptr++] = ua[t];
      } else if (
        navigator.appName == 'Netscape' &&
        navigator.appVersion < '5'
      ) {
        // 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;

  // 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;

  if (typeof exports !== 'undefined') {
    exports = module.exports = {
      default: BigInteger,
      BigInteger: BigInteger,
      SecureRandom: SecureRandom,
    };
  } else {
    this.jsbn = {
      BigInteger: BigInteger,
      SecureRandom: SecureRandom,
    };
  }
}.call(this));