jsbn.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 (!(this instanceof BigInteger)) {
    return new 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);
  }
}

var proto = BigInteger.prototype;

// 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;
}

// wtf?
BigInteger.prototype.am = am1;
dbits = 26;

/*
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);
var DV = 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 self = this;

  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 { self.fromRadix(s,b); return; }
  self.t = 0;
  self.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)
      self[self.t++] = x;
    else if(sh+k > self.DB) {
      self[self.t-1] |= (x&((1<<(self.DB-sh))-1))<<sh;
      self[self.t++] = (x>>(self.DB-sh));
    }
    else
      self[self.t-1] |= x<<sh;
    sh += k;
    if(sh >= self.DB) sh -= self.DB;
  }
  if(k == 8 && (s[0]&0x80) != 0) {
    self.s = -1;
    if(sh > 0) self[self.t-1] |= ((1<<(self.DB-sh))-1)<<sh;
  }
  self.clamp();
  if(mi) BigInteger.ZERO.subTo(self,self);
}

// (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) {
  var self = this;
  if(self.s < 0) return "-"+self.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 self.toRadix(b);
  var km = (1<<k)-1, d, m = false, r = "", i = self.t;
  var p = self.DB-(i*self.DB)%k;
  if(i-- > 0) {
    if(p < self.DB && (d = self[i]>>p) > 0) { m = true; r = int2char(d); }
    while(i >= 0) {
      if(p < k) {
        d = (self[i]&((1<<p)-1))<<(k-p);
        d |= self[--i]>>(p+=self.DB-k);
      }
      else {
        d = (self[i]>>(p-=k))&km;
        if(p <= 0) { p += self.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 self = this;
  var bs = n%self.DB;
  var cbs = self.DB-bs;
  var bm = (1<<cbs)-1;
  var ds = Math.floor(n/self.DB), c = (self.s<<bs)&self.DM, i;
  for(i = self.t-1; i >= 0; --i) {
    r[i+ds+1] = (self[i]>>cbs)|c;
    c = (self[i]&bm)<<bs;
  }
  for(i = ds-1; i >= 0; --i) r[i] = 0;
  r[ds] = c;
  r.t = self.t+ds+1;
  r.s = self.s;
  r.clamp();
}

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

// (protected) r = this - a
function bnpSubTo(a,r) {
  var self = this;
  var i = 0, c = 0, m = Math.min(a.t,self.t);
  while(i < m) {
    c += self[i]-a[i];
    r[i++] = c&self.DM;
    c >>= self.DB;
  }
  if(a.t < self.t) {
    c -= a.s;
    while(i < self.t) {
      c += self[i];
      r[i++] = c&self.DM;
      c >>= self.DB;
    }
    c += self.s;
  }
  else {
    c += self.s;
    while(i < a.t) {
      c -= a[i];
      r[i++] = c&self.DM;
      c >>= self.DB;
    }
    c -= a.s;
  }
  r.s = (c<0)?-1:0;
  if(c < -1) r[i++] = self.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 self = this;
  var pm = m.abs();
  if(pm.t <= 0) return;
  var pt = self.abs();
  if(pt.t < pm.t) {
    if(q != null) q.fromInt(0);
    if(r != null) self.copyTo(r);
    return;
  }
  if(r == null) r = nbi();
  var y = nbi(), ts = self.s, ms = m.s;
  var nsh = self.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<<self.F1)+((ys>1)?y[ys-2]>>self.F2:0);
  var d1 = self.FV/yt, d2 = (1<<self.F1)/yt, e = 1<<self.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)?self.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
proto.copyTo = bnpCopyTo;
proto.fromInt = bnpFromInt;
proto.fromString = bnpFromString;
proto.clamp = bnpClamp;
proto.dlShiftTo = bnpDLShiftTo;
proto.drShiftTo = bnpDRShiftTo;
proto.lShiftTo = bnpLShiftTo;
proto.rShiftTo = bnpRShiftTo;
proto.subTo = bnpSubTo;
proto.multiplyTo = bnpMultiplyTo;
proto.squareTo = bnpSquareTo;
proto.divRemTo = bnpDivRemTo;
proto.invDigit = bnpInvDigit;
proto.isEven = bnpIsEven;
proto.exp = bnpExp;

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

//// jsbn2

function nbi() { return new BigInteger(null); }

// (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) {
  var self = this;
  self.fromInt(0);
  if(b == null) b = 10;
  var cs = self.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) == "-" && self.signum() == 0) mi = true;
      continue;
    }
    w = b*w+x;
    if(++j >= cs) {
      self.dMultiply(d);
      self.dAddOffset(w,0);
      j = 0;
      w = 0;
    }
  }
  if(j > 0) {
    self.dMultiply(Math.pow(b,j));
    self.dAddOffset(w,0);
  }
  if(mi) BigInteger.ZERO.subTo(self,self);
}

// (protected) alternate constructor
function bnpFromNumber(a,b,c) {
  var self = this;
  if("number" == typeof b) {
    // new BigInteger(int,int,RNG)
    if(a < 2) self.fromInt(1);
    else {
      self.fromNumber(a,c);
      if(!self.testBit(a-1))	// force MSB set
        self.bitwiseTo(BigInteger.ONE.shiftLeft(a-1),op_or,self);
      if(self.isEven()) self.dAddOffset(1,0); // force odd
      while(!self.isProbablePrime(b)) {
        self.dAddOffset(2,0);
        if(self.bitLength() > a) self.subTo(BigInteger.ONE.shiftLeft(a-1),self);
      }
    }
  }
  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;
    self.fromString(x,256);
  }
}

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

  var i = 0, c = 0, m = Math.min(a.t,self.t);
  while(i < m) {
    c += self[i]+a[i];
    r[i++] = c&self.DM;
    c >>= self.DB;
  }
  if(a.t < self.t) {
    c += a.s;
    while(i < self.t) {
      c += self[i];
      r[i++] = c&self.DM;
      c >>= self.DB;
    }
    c += self.s;
  }
  else {
    c += self.s;
    while(i < a.t) {
      c += a[i];
      r[i++] = c&self.DM;
      c >>= self.DB;
    }
    c += a.s;
  }
  r.s = (c<0)?-1:0;
  if(c > 0) r[i++] = c;
  else if(c < -1) r[i++] = self.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) {
  var self = this;
  x.drShiftTo(self.m.t-1,self.r2);
  if(x.t > self.m.t+1) { x.t = self.m.t+1; x.clamp(); }
  self.mu.multiplyUpperTo(self.r2,self.m.t+1,self.q3);
  self.m.multiplyLowerTo(self.q3,self.m.t+1,self.r2);
  while(x.compareTo(self.r2) < 0) x.dAddOffset(1,self.m.t+1);
  x.subTo(self.r2,x);
  while(x.compareTo(self.m) >= 0) x.subTo(self.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;
}

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

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

// JSBN-specific extension
proto.square = bnSquare;

// BigInteger interfaces not implemented in jsbn:

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

// "constants"
BigInteger.ZERO = nbv(0);
BigInteger.ONE = nbv(1);
BigInteger.valueOf = nbv;


/// bitcoinjs addons

/**
 * Turns a byte array into a big integer.
 *
 * This function will interpret a byte array as a big integer in big
 * endian notation and ignore leading zeros.
 */
BigInteger.fromByteArrayUnsigned = function(ba) {
  if (!ba.length) {
    return new BigInteger.valueOf(0);
  } else if (ba[0] & 0x80) {
    // Prepend a zero so the BigInteger class doesn't mistake this
    // for a negative integer.
    return new BigInteger([0].concat(ba));
  } else {
    return new BigInteger(ba);
  }
};

/**
 * Parse a signed big integer byte representation.
 *
 * For details on the format please see BigInteger.toByteArraySigned.
 */
BigInteger.fromByteArraySigned = function(ba) {
  // Check for negative value
  if (ba[0] & 0x80) {
    // Remove sign bit
    ba[0] &= 0x7f;

    return BigInteger.fromByteArrayUnsigned(ba).negate();
  } else {
    return BigInteger.fromByteArrayUnsigned(ba);
  }
};

/**
 * Returns a byte array representation of the big integer.
 *
 * This returns the absolute of the contained value in big endian
 * form. A value of zero results in an empty array.
 */
BigInteger.prototype.toByteArrayUnsigned = function() {
    var ba = this.abs().toByteArray();

    // Empty array, nothing to do
    if (!ba.length) {
        return ba;
    }

    // remove leading 0
    if (ba[0] === 0) {
        ba = ba.slice(1);
    }

    // all values must be positive
    for (var i=0 ; i<ba.length ; ++i) {
      ba[i] = (ba[i] < 0) ? ba[i] + 256 : ba[i];
    }

    return ba;
};

/*
 * Converts big integer to signed byte representation.
 *
 * The format for this value uses the most significant bit as a sign
 * bit. If the most significant bit is already occupied by the
 * absolute value, an extra byte is prepended and the sign bit is set
 * there.
 *
 * Examples:
 *
 *      0 =>     0x00
 *      1 =>     0x01
 *     -1 =>     0x81
 *    127 =>     0x7f
 *   -127 =>     0xff
 *    128 =>   0x0080
 *   -128 =>   0x8080
 *    255 =>   0x00ff
 *   -255 =>   0x80ff
 *  16300 =>   0x3fac
 * -16300 =>   0xbfac
 *  62300 => 0x00f35c
 * -62300 => 0x80f35c
*/
BigInteger.prototype.toByteArraySigned = function() {
  var val = this.toByteArrayUnsigned();
  var neg = this.s < 0;

  // if the first bit is set, we always unshift
  // either unshift 0x80 or 0x00
  if (val[0] & 0x80) {
    val.unshift((neg) ? 0x80 : 0x00);
  }
  // if the first bit isn't set, set it if negative
  else if (neg) {
    val[0] |= 0x80;
  }

  return val;
};

module.exports = BigInteger;