rsa && sha1 js code

jsbn.js

/*
 * Copyright (c) 2003-2005  Tom Wu
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
 *
 * IN NO EVENT SHALL TOM WU BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
 * INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER
 * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT ADVISED OF
 * THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * In addition, the following condition applies:
 *
 * All redistributions must retain an intact copy of this copyright notice
 * and disclaimer.
 */

// 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.charCodeAt(i)&0xff:intAt(s,i);   /** MODIFIED **/
    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 == 256) k = 8; // byte array      /** MODIFIED **/
  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 = (k==8)?String.fromCharCode(d):int2char(d); }   /** MODIFIED **/
    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 += (k==8)?String.fromCharCode(d):int2char(d);    /** MODIFIED **/
    }
  }
  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);

sha1.js

/**
 *
 *  Secure Hash Algorithm (SHA1)
 *  http://www.webtoolkit.info/
 *
 **/

function SHA1(msg) {

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

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

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

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

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


    function Utf8Encode(string) {
        string = string.replace(/
/g,"
");
        var utftext = "";

        for (var n = 0; n < string.length; n++) {

            var c = string.charCodeAt(n);

            if (c < 128) {
                utftext += String.fromCharCode(c);
            }
            else if((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);
            }
            else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }

        }

        return utftext;
    };

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

    msg = Utf8Encode(msg);

    var msg_len = msg.length;

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

    switch( msg_len % 4 ) {
        case 0:
            i = 0x080000000;
        break;
        case 1:
            i = msg.charCodeAt(msg_len-1)<<24 | 0x0800000;
        break;

        case 2:
            i = msg.charCodeAt(msg_len-2)<<24 | msg.charCodeAt(msg_len-1)<<16 | 0x08000;
        break;

        case 3:
            i = msg.charCodeAt(msg_len-3)<<24 | msg.charCodeAt(msg_len-2)<<16 | msg.charCodeAt(msg_len-1)<<8    | 0x80;
        break;
    }

    word_array.push( i );

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

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


    for ( blockstart=0; blockstart<word_array.length; blockstart+=16 ) {

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

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

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

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

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

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

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

    }

    var temp = cvt_hex(H0) + cvt_hex(H1) + cvt_hex(H2) + cvt_hex(H3) + cvt_hex(H4);

    return temp.toLowerCase();
}

rsa.js

/**
 * This is a specialized RSA library meant only to verify SHA1-based signatures.
 * It requires jsbn.js and sha1.js to work.
 */

(function(globalObj)
{
  // Define ASN.1 templates for the data structures used
  function seq()
  {
    return {type: 0x30, children: Array.prototype.slice.call(arguments)};
  }
  function obj(id)
  {
    return {type: 0x06, content: id};
  }
  function bitStr(contents)
  {
    return {type: 0x03, encapsulates: contents};
  }
  function intResult(id)
  {
    return {type: 0x02, out: id};
  }
  function octetResult(id)
  {
    return {type: 0x04, out: id};
  }

  // See http://www.cryptopp.com/wiki/Keys_and_Formats#RSA_PublicKey
  // 2A 86 48 86 F7 0D 01 01 01 means 1.2.840.113549.1.1.1
  var publicKeyTemplate = seq(seq(obj("x2Ax86x48x86xF7x0Dx01x01x01"), {}), bitStr(seq(intResult("n"), intResult("e"))));

  // See http://tools.ietf.org/html/rfc3447#section-9.2 step 2
  // 2B 0E 03 02 1A means 1.3.14.3.2.26
  var signatureTemplate = seq(seq(obj("x2Bx0Ex03x02x1A"), {}), octetResult("sha1"));

  /**
   * Reads ASN.1 data matching the template passed in. This will throw an
   * exception if the data format doesn't match the template. On success an
   * object containing result properties is returned.
   *
   * See http://luca.ntop.org/Teaching/Appunti/asn1.html for info on the format.
   */
  function readASN1(data, templ)
  {
    var pos = 0;
    function next()
    {
      return data.charCodeAt(pos++);
    }

    function readLength()
    {
      var len = next();
      if (len & 0x80)
      {
        var cnt = len & 0x7F;
        if (cnt > 2 || cnt == 0)
          throw "Unsupported length";

        len = 0;
        for (var i = 0; i < cnt; i++)
          len += next() << (cnt - 1 - i) * 8;
        return len;
      }
      else
        return len;
    }

    function readNode(curTempl)
    {
      var type = next();
      var len = readLength();
      if ("type" in curTempl && curTempl.type != type)
        throw "Unexpected type";
      if ("content" in curTempl && curTempl.content != data.substr(pos, len))
        throw "Unexpected content";
      if ("out" in curTempl)
        out[curTempl.out] = new BigInteger(data.substr(pos, len), 256);
      if ("children" in curTempl)
      {
        var i, end;
        for (i = 0, end = pos + len; pos < end; i++)
        {
          if (i >= curTempl.children.length)
            throw "Too many children";
          readNode(curTempl.children[i]);
        }
        if (i < curTempl.children.length)
          throw "Too few children";
        if (pos > end)
          throw "Children too large";
      }
      else if ("encapsulates" in curTempl)
      {
        if (next() != 0)
          throw "Encapsulation expected";
        readNode(curTempl.encapsulates);
      }
      else
        pos += len;
    }

    var out = {};
    readNode(templ);
    if (pos != data.length)
      throw "Too much data";
    return out;
  }

  /**
   * Reads a BER-encoded RSA public key. On success returns an object with the
   * properties n and e (the components of the key), otherwise null.
   */
  function readPublicKey(key)
  {
    try
    {
      return readASN1(atob(key), publicKeyTemplate);
    }
    catch (e)
    {
      console.log("Invalid RSA public key: " + e);
      return null;
    }
  }

  /**
   * Checks whether the signature is valid for the given public key and data.
   */
  function verifySignature(key, signature, data)
  {
    var keyData = readPublicKey(key);
    if (!keyData)
      return false;

    // We need the exponent as regular number
    keyData.e = parseInt(keyData.e.toString(16), 16);

    // Decrypt signature data using RSA algorithm
    var sigInt = new BigInteger(atob(signature), 256);
    var digest = sigInt.modPowInt(keyData.e, keyData.n).toString(256);

    try
    {
      var pos = 0;
      function next()
      {
        return digest.charCodeAt(pos++);
      }

      // Skip padding, see http://tools.ietf.org/html/rfc3447#section-9.2 step 5
      if (next() != 1)
        throw "Wrong padding in signature digest";
      while (next() == 255) {}
      if (digest.charCodeAt(pos - 1) != 0)
        throw "Wrong padding in signature digest";

      // Rest is an ASN.1 structure, get the SHA1 hash from it and compare to
      // the real one
      var sha1 = readASN1(digest.substr(pos), signatureTemplate).sha1;
      var expected = new BigInteger(SHA1(data), 16);
      return (sha1.compareTo(expected) == 0);
    }
    catch (e)
    {
      console.log("Invalid encrypted signature: " + e);
      return false;
    }
  }

  // Export verifySignature function, everything else is private.
  globalObj.verifySignature = verifySignature;
})(this);