diff --git a/lib/crypto/bn.js b/lib/crypto/bn.js
index 67881868b..885f81a64 100644
--- a/lib/crypto/bn.js
+++ b/lib/crypto/bn.js
@@ -1,6 +1,8 @@
 'use strict';
 
 var _BN = require('bn.js');
+var $ = require('../util/preconditions');
+var _ = require('lodash');
 
 var BN = function BN(n, base) {
   if (!(this instanceof BN)) {
@@ -14,25 +16,23 @@ BN.prototype = _BN.prototype;
 var reversebuf = function(buf) {
   var buf2 = new Buffer(buf.length);
   for (var i = 0; i < buf.length; i++) {
-    buf2[i] = buf[buf.length-1-i];
+    buf2[i] = buf[buf.length - 1 - i];
   }
   return buf2;
 };
 
-BN.prototype.fromNumber = function(n) {
-  var bn = BN(n);
-  bn.copy(this);
-  return this;
+BN.fromNumber = function(n) {
+  $.checkArgument(_.isNumber(n));
+  return BN(n);
 };
 
 BN.prototype.toNumber = function() {
-  return parseInt(this['toString'](10), 10);
+  return parseInt(this.toString(10), 10);
 };
 
-BN.prototype.fromString = function(str) {
-  var bn = BN(str);
-  bn.copy(this);
-  return this;
+BN.fromString = function(str) {
+  $.checkArgument(_.isString(str));
+  return BN(str);
 };
 
 BN.fromBuffer = function(buf, opts) {
@@ -44,38 +44,37 @@ BN.fromBuffer = function(buf, opts) {
   return bn;
 };
 
-BN.prototype.fromBuffer = function(buf, opts) {
-  var bn = BN.fromBuffer(buf, opts);
-  bn.copy(this);
+BN.trim = function(buf, natlen) {
+  return buf.slice(natlen - buf.length, buf.length);
+};
 
-  return this;
+BN.pad = function(buf, natlen, size) {
+  var rbuf = new Buffer(size);
+  for (var i = 0; i < buf.length; i++) {
+    rbuf[rbuf.length - 1 - i] = buf[buf.length - 1 - i];
+  }
+  for (i = 0; i < size - natlen; i++) {
+    rbuf[i] = 0;
+  }
+  return rbuf;
 };
 
 BN.prototype.toBuffer = function(opts) {
-  var buf;
+  var buf, hex;
   if (opts && opts.size) {
-    var hex = this.toString(16, 2);
-    var natlen = hex.length/2;
+    hex = this.toString(16, 2);
+    var natlen = hex.length / 2;
     buf = new Buffer(hex, 'hex');
 
-    if (natlen == opts.size)
+    if (natlen === opts.size) {
       buf = buf;
-
-    else if (natlen > opts.size) {
-      buf = buf.slice(natlen - buf.length, buf.length);
+    } else if (natlen > opts.size) {
+      buf = BN.trim(buf, natlen);
+    } else if (natlen < opts.size) {
+      buf = BN.pad(buf, natlen, opts.size);
     }
-
-    else if (natlen < opts.size) {
-      var rbuf = new Buffer(opts.size);
-      for (var i = 0; i < buf.length; i++)
-        rbuf[rbuf.length-1-i] = buf[buf.length-1-i];
-      for (var i = 0; i < opts.size - natlen; i++)
-        rbuf[i] = 0;
-      buf = rbuf;
-    }
-  }
-  else {
-    var hex = this.toString(16, 2);
+  } else {
+    hex = this.toString(16, 2);
     buf = new Buffer(hex, 'hex');
   }
 
@@ -88,51 +87,58 @@ BN.prototype.toBuffer = function(opts) {
 
 // signed magnitude buffer
 // most significant bit represents sign (0 = positive, -1 = negative)
-BN.prototype.fromSM = function(buf, opts) {
-  if (buf.length === 0)
-    this.fromBuffer(new Buffer([0]));
+BN.fromSM = function(buf, opts) {
+  var ret;
+  if (buf.length === 0) {
+    return BN.fromBuffer(new Buffer([0]));
+  }
 
   var endian = 'big';
-  if (opts)
+  if (opts) {
     endian = opts.endian;
-
-  if (endian == 'little')
+  }
+  if (endian === 'little') {
     buf = reversebuf(buf);
+  }
 
   if (buf[0] & 0x80) {
     buf[0] = buf[0] & 0x7f;
-    this.fromBuffer(buf);
-    this.neg().copy(this);
+    ret = BN.fromBuffer(buf);
+    ret.neg().copy(ret);
   } else {
-    this.fromBuffer(buf);
+    ret = BN.fromBuffer(buf);
   }
-  return this;
+  return ret;
 };
 
-BN.prototype.toSM = function(opts) {
-  var endian = 'big';
-  if (opts)
-    endian = opts.endian;
-
+BN.prototype.toSMBigEndian = function() {
   var buf;
-  if (this.cmp(0) == -1) {
+  if (this.cmp(0) === -1) {
     buf = this.neg().toBuffer();
-    if (buf[0] & 0x80)
+    if (buf[0] & 0x80) {
       buf = Buffer.concat([new Buffer([0x80]), buf]);
-    else
+    } else {
       buf[0] = buf[0] | 0x80;
+    }
   } else {
     buf = this.toBuffer();
-    if (buf[0] & 0x80)
+    if (buf[0] & 0x80) {
       buf = Buffer.concat([new Buffer([0x00]), buf]);
+    }
   }
 
-  if (buf.length === 1 & buf[0] === 0)
+  if (buf.length === 1 & buf[0] === 0) {
     buf = new Buffer([]);
+  }
+  return buf;
+};
+BN.prototype.toSM = function(opts) {
+  var endian = opts ? opts.endian : 'big';
+  var buf = this.toSMBigEndian();
 
-  if (endian == 'little')
+  if (endian === 'little') {
     buf = reversebuf(buf);
-
+  }
   return buf;
 };
 
@@ -140,10 +146,9 @@ BN.prototype.toSM = function(opts) {
 // bitcoind's script interpreter use CScriptNum, which is not really a proper
 // bignum. Instead, an error is thrown if trying to input a number bigger than
 // 4 bytes. We copy that behavior here.
-BN.prototype.fromScriptNumBuffer = function(buf, fRequireMinimal) {
+BN.fromScriptNumBuffer = function(buf, fRequireMinimal) {
   var nMaxNumSize = 4;
-  if (buf.length > nMaxNumSize)
-    throw new Error('script number overflow');
+  $.checkArgument(buf.length <= nMaxNumSize, new Error('script number overflow'));
   if (fRequireMinimal && buf.length > 0) {
     // Check that the number is encoded with the minimum possible
     // number of bytes.
@@ -158,28 +163,33 @@ BN.prototype.fromScriptNumBuffer = function(buf, fRequireMinimal) {
       // is +-255, which encode to 0xff00 and 0xff80 respectively.
       // (big-endian).
       if (buf.length <= 1 || (buf[buf.length - 2] & 0x80) === 0) {
-        throw new Error("non-minimally encoded script number");
+        throw new Error('non-minimally encoded script number');
       }
     }
   }
-  return this.fromSM(buf, {endian: 'little'});
+  return BN.fromSM(buf, {
+    endian: 'little'
+  });
 };
 
 // The corollary to the above, with the notable exception that we do not throw
 // an error if the output is larger than four bytes. (Which can happen if
 // performing a numerical operation that results in an overflow to more than 4
 // bytes).
-BN.prototype.toScriptNumBuffer = function(buf) {
-  return this.toSM({endian: 'little'});
+BN.prototype.toScriptNumBuffer = function() {
+  return this.toSM({
+    endian: 'little'
+  });
 };
 
-function decorate(name) {
+var decorate = function decorate(name) {
   BN.prototype['_' + name] = BN.prototype[name];
   var f = function(b) {
-    if (typeof b === 'string')
+    if (typeof b === 'string') {
       b = new BN(b);
-    else if (typeof b === 'number')
+    } else if (typeof b === 'number') {
       b = new BN(b.toString());
+    }
     return this['_' + name](b);
   };
   BN.prototype[name] = f;
diff --git a/lib/crypto/ecdsa.js b/lib/crypto/ecdsa.js
index 2b1081e8b..6e5c09146 100644
--- a/lib/crypto/ecdsa.js
+++ b/lib/crypto/ecdsa.js
@@ -4,9 +4,11 @@ var BN = require('./bn');
 var Point = require('./point');
 var Signature = require('./signature');
 var PublicKey = require('../publickey');
-var PrivateKey = require('../privatekey');
 var Random = require('./random');
 var Hash = require('./hash');
+var BufferUtil = require('../util/buffer');
+var _ = require('lodash');
+var $ = require('../util/preconditions');
 
 var ECDSA = function ECDSA(obj) {
   if (!(this instanceof ECDSA)) {
@@ -17,6 +19,7 @@ var ECDSA = function ECDSA(obj) {
   }
 };
 
+/* jshint maxcomplexity: 9 */
 ECDSA.prototype.set = function(obj) {
   this.hashbuf = obj.hashbuf || this.hashbuf;
   this.endian = obj.endian || this.endian; //the endianness of hashbuf
@@ -37,7 +40,7 @@ ECDSA.prototype.calci = function() {
     this.sig.i = i;
     var Qprime;
     try {
-      Qprime = this.sig2pubkey();
+      Qprime = this.toPublicKey();
     } catch (e) {
       console.error(e);
       continue;
@@ -53,61 +56,48 @@ ECDSA.prototype.calci = function() {
   throw new Error('Unable to find valid recovery factor');
 };
 
-ECDSA.prototype.fromString = function(str) {
+ECDSA.fromString = function(str) {
   var obj = JSON.parse(str);
-  if (obj.hashbuf) {
-    this.hashbuf = new Buffer(obj.hashbuf, 'hex');
-  }
-  if (obj.pubkey) {
-    this.pubkey = PublicKey.fromString(obj.pubkey);
-  }
-  if (obj.privkey) {
-    this.privkey = PrivateKey.fromString(obj.privkey);
-  }
-  if (obj.sig) {
-    this.sig = Signature.fromString(obj.sig);
-  }
-  if (obj.k) {
-    this.k = BN(obj.k, 10);
-  }
-  return this;
+  return new ECDSA(obj);
 };
 
 ECDSA.prototype.randomK = function() {
   var N = Point.getN();
   var k;
   do {
-    k = BN().fromBuffer(Random.getRandomBuffer(32));
+    k = BN.fromBuffer(Random.getRandomBuffer(32));
   } while (!(k.lt(N) && k.gt(0)));
   this.k = k;
   return this;
 };
 
+
 // https://tools.ietf.org/html/rfc6979#section-3.2
 ECDSA.prototype.deterministicK = function(badrs) {
+  /* jshint maxstatements: 25 */
+  if (_.isUndefined(badrs)) {
+    badrs = 0;
+  }
   var v = new Buffer(32);
   v.fill(0x01);
   var k = new Buffer(32);
   k.fill(0x00);
-  var x = this.privkey.bn.toBuffer({size: 32});
+  var x = this.privkey.bn.toBuffer({
+    size: 32
+  });
   k = Hash.sha256hmac(Buffer.concat([v, new Buffer([0x00]), x, this.hashbuf]), k);
   v = Hash.sha256hmac(v, k);
   k = Hash.sha256hmac(Buffer.concat([v, new Buffer([0x01]), x, this.hashbuf]), k);
   v = Hash.sha256hmac(v, k);
   v = Hash.sha256hmac(v, k);
-  var T = BN().fromBuffer(v);
+  var T = BN.fromBuffer(v);
   var N = Point.getN();
 
-  // if r or s were invalid when this function was used in signing,
-  // we do not want to actually compute r, s here for efficiency, so,
-  // we can increment badrs. explained at end of RFC 6979 section 3.2
-  if (typeof badrs === 'undefined')
-    badrs = 0;
   // also explained in 3.2, we must ensure T is in the proper range (0, N)
   for (var i = 0; i < badrs || !(T.lt(N) && T.gt(0)); i++) {
     k = Hash.sha256hmac(Buffer.concat([v, new Buffer([0x00])]), k);
     v = Hash.sha256hmac(v, k);
-    T = BN().fromBuffer(v);
+    T = BN.fromBuffer(v);
   }
 
   this.k = T;
@@ -117,12 +107,12 @@ ECDSA.prototype.deterministicK = function(badrs) {
 // Information about public key recovery:
 // https://bitcointalk.org/index.php?topic=6430.0
 // http://stackoverflow.com/questions/19665491/how-do-i-get-an-ecdsa-public-key-from-just-a-bitcoin-signature-sec1-4-1-6-k
-ECDSA.prototype.sig2pubkey = function() {
+ECDSA.prototype.toPublicKey = function() {
+  /* jshint maxstatements: 25 */
   var i = this.sig.i;
-  if (!(i === 0 || i === 1 || i === 2 || i === 3))
-    throw new Error('i must be equal to 0, 1, 2, or 3');
+  $.checkArgument(i === 0 || i === 1 || i === 2 || i === 3, new Error('i must be equal to 0, 1, 2, or 3'));
 
-  var e = BN().fromBuffer(this.hashbuf);
+  var e = BN.fromBuffer(this.hashbuf);
   var r = this.sig.r;
   var s = this.sig.s;
 
@@ -143,8 +133,9 @@ ECDSA.prototype.sig2pubkey = function() {
   // 1.4 Check that nR is at infinity
   var nR = R.mul(n);
 
-  if (!nR.isInfinity())
+  if (!nR.isInfinity()) {
     throw new Error('nR is not a valid curve point');
+  }
 
   // Compute -e from e
   var eNeg = e.neg().mod(n);
@@ -162,67 +153,87 @@ ECDSA.prototype.sig2pubkey = function() {
 };
 
 ECDSA.prototype.sigError = function() {
-  if (!Buffer.isBuffer(this.hashbuf) || this.hashbuf.length !== 32) {
+  /* jshint maxstatements: 25 */
+  if (!BufferUtil.isBuffer(this.hashbuf) || this.hashbuf.length !== 32) {
     return 'hashbuf must be a 32 byte buffer';
   }
 
   var r = this.sig.r;
   var s = this.sig.s;
-  if (!(r.gt(0) && r.lt(Point.getN()))
-   || !(s.gt(0) && s.lt(Point.getN())))
+  if (!(r.gt(0) && r.lt(Point.getN())) || !(s.gt(0) && s.lt(Point.getN()))) {
     return 'r and s not in range';
+  }
 
-  var e = BN().fromBuffer(this.hashbuf, this.endian ? {endian: this.endian} : undefined);
+  var e = BN.fromBuffer(this.hashbuf, this.endian ? {
+    endian: this.endian
+  } : undefined);
   var n = Point.getN();
   var sinv = s.invm(n);
   var u1 = sinv.mul(e).mod(n);
   var u2 = sinv.mul(r).mod(n);
 
   var p = Point.getG().mulAdd(u1, this.pubkey.point, u2);
-  if (p.isInfinity())
+  if (p.isInfinity()) {
     return 'p is infinity';
+  }
 
-  if (!(p.getX().mod(n).cmp(r) === 0))
+  if (p.getX().mod(n).cmp(r) !== 0) {
     return 'Invalid signature';
-  else
+  } else {
     return false;
+  }
+};
+
+ECDSA.toLowS = function(s) {
+  //enforce low s
+  //see BIP 62, "low S values in signatures"
+  if (s.gt(BN.fromBuffer(new Buffer('7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0', 'hex')))) {
+    s = Point.getN().sub(s);
+  }
+  return s;
+};
+
+ECDSA.prototype._findSignature = function(d, e) {
+  var N = Point.getN();
+  var G = Point.getG();
+  // try different values of k until r, s are valid
+  var badrs = 0;
+  var k, Q, r, s;
+  do {
+    if (!this.k || badrs > 0) {
+      this.deterministicK(badrs);
+    }
+    badrs++;
+    k = this.k;
+    Q = G.mul(k);
+    r = Q.x.mod(N);
+    s = k.invm(N).mul(e.add(d.mul(r))).mod(N);
+  } while (r.cmp(0) <= 0 || s.cmp(0) <= 0);
+
+  s = ECDSA.toLowS(s);
+  return {
+    s: s,
+    r: r
+  };
+
 };
 
 ECDSA.prototype.sign = function() {
   var hashbuf = this.hashbuf;
   var privkey = this.privkey;
-
   var d = privkey.bn;
 
-  if (!hashbuf || !privkey || !d)
-    throw new Error('invalid parameters');
+  $.checkState(hashbuf && privkey && d, new Error('invalid parameters'));
+  $.checkState(BufferUtil.isBuffer(hashbuf) && hashbuf.length === 32, new Error('hashbuf must be a 32 byte buffer'));
 
-  if (!Buffer.isBuffer(hashbuf) || hashbuf.length !== 32)
-    throw new Error('hashbuf must be a 32 byte buffer');
+  var e = BN.fromBuffer(hashbuf, this.endian ? {
+    endian: this.endian
+  } : undefined);
 
-  var N = Point.getN();
-  var G = Point.getG();
-  var e = BN().fromBuffer(hashbuf, this.endian ? {endian: this.endian} : undefined);
+  var obj = this._findSignature(d, e);
+  obj.compressed = this.pubkey.compressed;
 
-  // try different values of k until r, s are valid
-  var badrs = 0;
-  do {
-    if (!this.k || badrs > 0)
-      this.deterministicK(badrs);
-    badrs++;
-    var k = this.k;
-    var Q = G.mul(k);
-    var r = Q.x.mod(N);
-    var s = k.invm(N).mul(e.add(d.mul(r))).mod(N);
-  } while (r.cmp(0) <= 0 || s.cmp(0) <= 0);
-
-  //enforce low s
-  //see BIP 62, "low S values in signatures"
-  if (s.gt(BN().fromBuffer(new Buffer('7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0', 'hex')))) {
-    s = Point.getN().sub(s);
-  }
-
-  this.sig = new Signature({r: r, s: s, compressed: this.pubkey.compressed});
+  this.sig = new Signature(obj);
   return this;
 };
 
@@ -252,10 +263,11 @@ ECDSA.prototype.toString = function() {
 };
 
 ECDSA.prototype.verify = function() {
-  if (!this.sigError())
+  if (!this.sigError()) {
     this.verified = true;
-  else
+  } else {
     this.verified = false;
+  }
   return this;
 };
 
diff --git a/lib/crypto/signature.js b/lib/crypto/signature.js
index f2b48935f..2ca0b3340 100644
--- a/lib/crypto/signature.js
+++ b/lib/crypto/signature.js
@@ -1,10 +1,14 @@
 'use strict';
 
 var BN = require('./bn');
+var _ = require('lodash');
+var $ = require('../util/preconditions');
+var BufferUtil = require('../util/buffer');
 
 var Signature = function Signature(r, s) {
-  if (!(this instanceof Signature))
+  if (!(this instanceof Signature)) {
     return new Signature(r, s);
+  }
   if (r instanceof BN) {
     this.set({
       r: r,
@@ -16,37 +20,32 @@ var Signature = function Signature(r, s) {
   }
 };
 
+/* jshint maxcomplexity: 7 */
 Signature.prototype.set = function(obj) {
   this.r = obj.r || this.r || undefined;
   this.s = obj.s || this.s || undefined;
   this.i = typeof obj.i !== 'undefined' ? obj.i : this.i; //public key recovery parameter in range [0, 3]
-  this.compressed = typeof obj.compressed !== 'undefined' ? obj.compressed : this.compressed; //whether the recovered pubkey is compressed
+  this.compressed = typeof obj.compressed !== 'undefined' ?
+    obj.compressed : this.compressed; //whether the recovered pubkey is compressed
   return this;
 };
 
 Signature.fromCompact = function(buf) {
   var sig = new Signature();
+  //TODO: handle uncompressed pubkeys
   var compressed = true;
   var i = buf.slice(0, 1)[0] - 27 - 4;
-  //TODO: handle uncompressed pubkeys
-
   var b2 = buf.slice(1, 33);
   var b3 = buf.slice(33, 65);
 
-  if (!(i === 0 || i === 1 || i === 2 || i === 3)) {
-    throw new Error('i must be 0, 1, 2, or 3');
-  }
-  if (b2.length !== 32) {
-    throw new Error('r must be 32 bytes');
-  }
-  if (b3.length !== 32) {
-    throw new Error('s must be 32 bytes');
-  }
+  $.checkArgument(i === 0 || i === 1 || i === 2 || i === 3, new Error('i must be 0, 1, 2, or 3'));
+  $.checkArgument(b2.length === 32, new Error('r must be 32 bytes'));
+  $.checkArgument(b3.length === 32, new Error('s must be 32 bytes'));
 
   sig.compressed = compressed;
   sig.i = i;
-  sig.r = BN().fromBuffer(b2);
-  sig.s = BN().fromBuffer(b3);
+  sig.r = BN.fromBuffer(b2);
+  sig.s = BN.fromBuffer(b3);
 
   return sig;
 };
@@ -80,58 +79,40 @@ Signature.fromString = function(str) {
  * In order to mimic the non-strict DER encoding of OpenSSL, set strict = false.
  */
 Signature.parseDER = function(buf, strict) {
-  if (typeof strict === 'undefined') {
+  $.checkArgument(BufferUtil.isBuffer(buf), new Error('DER formatted signature should be a buffer'));
+  if (_.isUndefined(strict)) {
     strict = true;
   }
 
-  if (!Buffer.isBuffer(buf)) {
-    throw new Error('DER formatted signature should be a buffer');
-  }
-
   var header = buf[0];
-
-  if (header !== 0x30) {
-    throw new Error('Header byte should be 0x30');
-  }
+  $.checkArgument(header === 0x30, new Error('Header byte should be 0x30'));
 
   var length = buf[1];
   var buflength = buf.slice(2).length;
-  if (strict && length !== buflength) {
-    throw new Error('Length byte should length of what follows');
-  } else {
-    length = length < buflength ? length : buflength;
-  }
+  $.checkArgument(!strict || length === buflength, new Error('Length byte should length of what follows'));
+
+  length = length < buflength ? length : buflength;
 
   var rheader = buf[2 + 0];
-  if (rheader !== 0x02) {
-    throw new Error('Integer byte for r should be 0x02');
-  }
+  $.checkArgument(rheader === 0x02, new Error('Integer byte for r should be 0x02'));
 
   var rlength = buf[2 + 1];
   var rbuf = buf.slice(2 + 2, 2 + 2 + rlength);
-  var r = BN().fromBuffer(rbuf);
+  var r = BN.fromBuffer(rbuf);
   var rneg = buf[2 + 1 + 1] === 0x00 ? true : false;
-  if (rlength !== rbuf.length) {
-    throw new Error('Length of r incorrect');
-  }
+  $.checkArgument(rlength === rbuf.length, new Error('Length of r incorrect'));
 
   var sheader = buf[2 + 2 + rlength + 0];
-  if (sheader !== 0x02) {
-    throw new Error('Integer byte for s should be 0x02');
-  }
+  $.checkArgument(sheader === 0x02, new Error('Integer byte for s should be 0x02'));
 
   var slength = buf[2 + 2 + rlength + 1];
   var sbuf = buf.slice(2 + 2 + rlength + 2, 2 + 2 + rlength + 2 + slength);
-  var s = BN().fromBuffer(sbuf);
+  var s = BN.fromBuffer(sbuf);
   var sneg = buf[2 + 2 + rlength + 2 + 2] === 0x00 ? true : false;
-  if (slength !== sbuf.length) {
-    throw new Error('Length of s incorrect');
-  }
+  $.checkArgument(slength === sbuf.length, new Error('Length of s incorrect'));
 
   var sumlength = 2 + 2 + rlength + 2 + slength;
-  if (length !== sumlength - 2) {
-    throw new Error('Length of signature incorrect');
-  }
+  $.checkArgument(length === sumlength - 2, new Error('Length of signature incorrect'));
 
   var obj = {
     header: header,
diff --git a/lib/encoding/bufferreader.js b/lib/encoding/bufferreader.js
index 6ed609a50..89f46452d 100644
--- a/lib/encoding/bufferreader.js
+++ b/lib/encoding/bufferreader.js
@@ -73,7 +73,7 @@ BufferReader.prototype.readUInt32LE = function() {
 
 BufferReader.prototype.readUInt64BEBN = function() {
   var buf = this.buf.slice(this.pos, this.pos + 8);
-  var bn = BN().fromBuffer(buf);
+  var bn = BN.fromBuffer(buf);
   this.pos = this.pos + 8;
   return bn;
 };
@@ -81,7 +81,7 @@ BufferReader.prototype.readUInt64BEBN = function() {
 BufferReader.prototype.readUInt64LEBN = function() {
   var buf = this.buf.slice(this.pos, this.pos + 8);
   var reversebuf = BufferReader({buf: buf}).readReverse();
-  var bn = BN().fromBuffer(reversebuf);
+  var bn = BN.fromBuffer(reversebuf);
   this.pos = this.pos + 8;
   return bn;
 };
diff --git a/lib/hdprivatekey.js b/lib/hdprivatekey.js
index 877f8803c..9d88f85fc 100644
--- a/lib/hdprivatekey.js
+++ b/lib/hdprivatekey.js
@@ -117,7 +117,7 @@ HDPrivateKey.prototype._deriveWithNumber = function(index, hardened) {
     data = BufferUtil.concat([this.publicKey.toBuffer(), indexBuffer]);
   }
   var hash = Hash.sha512hmac(data, this._buffers.chainCode);
-  var leftPart = BN().fromBuffer(hash.slice(0, 32), {size: 32});
+  var leftPart = BN.fromBuffer(hash.slice(0, 32), {size: 32});
   var chainCode = hash.slice(32, 64);
 
   var privateKey = leftPart.add(this.privateKey.toBigNumber()).mod(Point.getN()).toBuffer({size: 32});
@@ -334,7 +334,7 @@ HDPrivateKey.prototype._buildFromBuffers = function(arg) {
     xprivkey = arg.xprivkey;
   }
 
-  var privateKey = new PrivateKey(BN().fromBuffer(arg.privateKey));
+  var privateKey = new PrivateKey(BN.fromBuffer(arg.privateKey));
   var publicKey = privateKey.toPublicKey();
   var size = HDPrivateKey.ParentFingerPrintSize;
   var fingerPrint = Hash.sha256ripemd160(publicKey.toBuffer()).slice(0, size);
diff --git a/lib/hdpublickey.js b/lib/hdpublickey.js
index 0dc3f50ed..63439ca46 100644
--- a/lib/hdpublickey.js
+++ b/lib/hdpublickey.js
@@ -110,7 +110,7 @@ HDPublicKey.prototype._deriveWithNumber = function (index, hardened) {
   var indexBuffer = BufferUtil.integerAsBuffer(index);
   var data = BufferUtil.concat([this.publicKey.toBuffer(), indexBuffer]);
   var hash = Hash.sha512hmac(data, this._buffers.chainCode);
-  var leftPart = BN().fromBuffer(hash.slice(0, 32), {size: 32});
+  var leftPart = BN.fromBuffer(hash.slice(0, 32), {size: 32});
   var chainCode = hash.slice(32, 64);
 
   var publicKey = PublicKey.fromPoint(Point.getG().mul(leftPart).add(this.publicKey.point));
@@ -219,7 +219,7 @@ HDPublicKey.prototype._buildFromJSON = function (arg) {
 
 HDPublicKey.prototype._buildFromPrivate = function (arg) {
   var args = _.clone(arg._buffers);
-  var point = Point.getG().mul(BN().fromBuffer(args.privateKey));
+  var point = Point.getG().mul(BN.fromBuffer(args.privateKey));
   args.publicKey = Point.pointToCompressed(point);
   args.version = BufferUtil.integerAsBuffer(Network.get(BufferUtil.integerFromBuffer(args.version)).xpubkey);
   args.privateKey = undefined;
diff --git a/lib/privatekey.js b/lib/privatekey.js
index 344f5ac8d..c0569fe54 100644
--- a/lib/privatekey.js
+++ b/lib/privatekey.js
@@ -128,7 +128,7 @@ PrivateKey._getRandomBN = function(){
   var bn;
   do {
     var privbuf = Random.getRandomBuffer(32);
-    bn = BN().fromBuffer(privbuf);
+    bn = BN.fromBuffer(privbuf);
     condition = bn.lt(Point.getN());
   } while (!condition);
   return bn;
diff --git a/lib/script/interpreter.js b/lib/script/interpreter.js
index 977da0f7a..a548db9e2 100644
--- a/lib/script/interpreter.js
+++ b/lib/script/interpreter.js
@@ -682,7 +682,7 @@ Interpreter.prototype.step = function() {
             return false;
           }
           buf = this.stack[this.stack.length - 1];
-          bn = BN().fromScriptNumBuffer(buf, fRequireMinimal);
+          bn = BN.fromScriptNumBuffer(buf, fRequireMinimal);
           n = bn.toNumber();
           this.stack.pop();
           if (n < 0 || n >= this.stack.length) {
@@ -769,11 +769,6 @@ Interpreter.prototype.step = function() {
           buf1 = this.stack[this.stack.length - 2];
           buf2 = this.stack[this.stack.length - 1];
           var fEqual = buf1.toString('hex') === buf2.toString('hex');
-          // Opcode.OP_NOTEQUAL is disabled because it would be too easy to say
-          // something like n != 1 and have some wiseguy pass in 1 with extra
-          // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)
-          //if (opcode == Opcode.OP_NOTEQUAL)
-          //  fEqual = !fEqual;
           this.stack.pop();
           this.stack.pop();
           this.stack.push(fEqual ? Interpreter.true : Interpreter.false);
@@ -805,7 +800,7 @@ Interpreter.prototype.step = function() {
             return false;
           }
           buf = this.stack[this.stack.length - 1];
-          bn = BN().fromScriptNumBuffer(buf, fRequireMinimal);
+          bn = BN.fromScriptNumBuffer(buf, fRequireMinimal);
           switch (opcodenum) {
             case Opcode.OP_1ADD:
               bn = bn.add(1);
@@ -853,8 +848,8 @@ Interpreter.prototype.step = function() {
             this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
             return false;
           }
-          bn1 = BN().fromScriptNumBuffer(this.stack[this.stack.length - 2], fRequireMinimal);
-          bn2 = BN().fromScriptNumBuffer(this.stack[this.stack.length - 1], fRequireMinimal);
+          bn1 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 2], fRequireMinimal);
+          bn2 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 1], fRequireMinimal);
           bn = BN(0);
 
           switch (opcodenum) {
@@ -933,9 +928,9 @@ Interpreter.prototype.step = function() {
             this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
             return false;
           }
-          bn1 = BN().fromScriptNumBuffer(this.stack[this.stack.length - 3], fRequireMinimal);
-          bn2 = BN().fromScriptNumBuffer(this.stack[this.stack.length - 2], fRequireMinimal);
-          var bn3 = BN().fromScriptNumBuffer(this.stack[this.stack.length - 1], fRequireMinimal);
+          bn1 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 3], fRequireMinimal);
+          bn2 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 2], fRequireMinimal);
+          var bn3 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 1], fRequireMinimal);
           //bool fValue = (bn2 <= bn1 && bn1 < bn3);
           fValue = (bn2.cmp(bn1) <= 0) && (bn1.cmp(bn3) < 0);
           this.stack.pop();
@@ -1048,7 +1043,7 @@ Interpreter.prototype.step = function() {
             return false;
           }
 
-          var nKeysCount = BN().fromScriptNumBuffer(this.stack[this.stack.length - i], fRequireMinimal).toNumber();
+          var nKeysCount = BN.fromScriptNumBuffer(this.stack[this.stack.length - i], fRequireMinimal).toNumber();
           if (nKeysCount < 0 || nKeysCount > 20) {
             this.errstr = 'SCRIPT_ERR_PUBKEY_COUNT';
             return false;
@@ -1066,7 +1061,7 @@ Interpreter.prototype.step = function() {
             return false;
           }
 
-          var nSigsCount = BN().fromScriptNumBuffer(this.stack[this.stack.length - i], fRequireMinimal).toNumber();
+          var nSigsCount = BN.fromScriptNumBuffer(this.stack[this.stack.length - i], fRequireMinimal).toNumber();
           if (nSigsCount < 0 || nSigsCount > nKeysCount) {
             this.errstr = 'SCRIPT_ERR_SIG_COUNT';
             return false;
diff --git a/lib/transaction/output.js b/lib/transaction/output.js
index e1a89c323..896f8335f 100644
--- a/lib/transaction/output.js
+++ b/lib/transaction/output.js
@@ -38,7 +38,7 @@ Object.defineProperty(Output.prototype, 'satoshis', {
     if (num instanceof BN) {
       this._satoshis = num;
     } else {
-      this._satoshis = BN().fromNumber(num);
+      this._satoshis = BN.fromNumber(num);
     }
   }
 });
diff --git a/lib/transaction/sighash.js b/lib/transaction/sighash.js
index 30ebf6f06..03c2485aa 100644
--- a/lib/transaction/sighash.js
+++ b/lib/transaction/sighash.js
@@ -73,7 +73,7 @@ var sighash = function sighash(transaction, sighashType, inputNumber, subscript)
 
     for (i = 0; i < inputNumber; i++) {
       txcopy.outputs[i] = new Output({
-        satoshis: BN().fromBuffer(new buffer.Buffer(BITS_64_ON, 'hex')),
+        satoshis: BN.fromBuffer(new buffer.Buffer(BITS_64_ON, 'hex')),
         script: Script.empty()
       });
     }
@@ -83,7 +83,7 @@ var sighash = function sighash(transaction, sighashType, inputNumber, subscript)
     txcopy.inputs = [txcopy.inputs[inputNumber]];
   }
 
-  var buf = BufferWriter()
+  var buf = new BufferWriter()
     .write(txcopy.toBuffer())
     .writeInt32LE(sighashType)
     .toBuffer();
diff --git a/test/crypto/bn.js b/test/crypto/bn.js
index a771ae0f9..c0af52191 100644
--- a/test/crypto/bn.js
+++ b/test/crypto/bn.js
@@ -22,7 +22,7 @@ describe('BN', function() {
     bn = new BN(Math.pow(2, 26));
     bn.toString().should.equal((Math.pow(2, 26)).toString());
   });
-  
+
   describe('#add', function() {
 
     it('should add two small numbers together', function() {
@@ -67,70 +67,81 @@ describe('BN', function() {
 
   });
 
-  describe('#fromString', function() {
-    
-    it('should make BN from a string', function() {
-      BN().fromString('5').toString().should.equal('5');
+  describe('to/from ScriptNumBuffer', function() {
+    [0, 1, 10, 256, 1000, 65536, 65537, -1, -1000, -65536, -65537].forEach(function(n) {
+      it('rountrips correctly for ' + n, function() {
+        BN.fromScriptNumBuffer(BN(n).toScriptNumBuffer()).toNumber().should.equal(n);
+      });
     });
+  });
 
+  describe('#fromString', function() {
+    it('should make BN from a string', function() {
+      BN.fromString('5').toString().should.equal('5');
+    });
   });
 
   describe('#toString', function() {
-    
     it('should make a string', function() {
       BN(5).toString().should.equal('5');
     });
-
   });
 
   describe('@fromBuffer', function() {
-    
+
     it('should work with big endian', function() {
-      var bn = BN.fromBuffer(new Buffer('0001', 'hex'), {endian: 'big'});
+      var bn = BN.fromBuffer(new Buffer('0001', 'hex'), {
+        endian: 'big'
+      });
       bn.toString().should.equal('1');
     });
 
     it('should work with big endian 256', function() {
-      var bn = BN.fromBuffer(new Buffer('0100', 'hex'), {endian: 'big'});
+      var bn = BN.fromBuffer(new Buffer('0100', 'hex'), {
+        endian: 'big'
+      });
       bn.toString().should.equal('256');
     });
 
     it('should work with little endian if we specify the size', function() {
-      var bn = BN.fromBuffer(new Buffer('0100', 'hex'), {size: 2, endian: 'little'});
+      var bn = BN.fromBuffer(new Buffer('0100', 'hex'), {
+        size: 2,
+        endian: 'little'
+      });
       bn.toString().should.equal('1');
     });
 
   });
 
-  describe('#fromBuffer', function() {
-
-    it('should work as a prototype method', function() {
-      var bn = BN().fromBuffer(new Buffer('0100', 'hex'), {size: 2, endian: 'little'});
-      bn.toString().should.equal('1');
-    });
-  
-  });
-
   describe('#toBuffer', function() {
-    
+
     it('should create a 4 byte buffer', function() {
       var bn = new BN(1);
-      bn.toBuffer({size: 4}).toString('hex').should.equal('00000001');
+      bn.toBuffer({
+        size: 4
+      }).toString('hex').should.equal('00000001');
     });
 
     it('should create a 4 byte buffer in little endian', function() {
       var bn = new BN(1);
-      bn.toBuffer({size: 4, endian: 'little'}).toString('hex').should.equal('01000000');
+      bn.toBuffer({
+        size: 4,
+        endian: 'little'
+      }).toString('hex').should.equal('01000000');
     });
 
     it('should create a 2 byte buffer even if you ask for a 1 byte', function() {
       var bn = new BN('ff00', 16);
-      bn.toBuffer({size: 1}).toString('hex').should.equal('ff00');
+      bn.toBuffer({
+        size: 1
+      }).toString('hex').should.equal('ff00');
     });
 
     it('should create a 4 byte buffer even if you ask for a 1 byte', function() {
       var bn = new BN('ffffff00', 16);
-      bn.toBuffer({size: 4}).toString('hex').should.equal('ffffff00');
+      bn.toBuffer({
+        size: 4
+      }).toString('hex').should.equal('ffffff00');
     });
 
   });
diff --git a/test/crypto/ecdsa.js b/test/crypto/ecdsa.js
index 9a918c021..79cd53bb4 100644
--- a/test/crypto/ecdsa.js
+++ b/test/crypto/ecdsa.js
@@ -10,42 +10,42 @@ var point = require('../../lib/crypto/point');
 var should = require('chai').should();
 var vectors = require('../data/ecdsa');
 
-describe("ECDSA", function() {
+describe('ECDSA', function() {
 
-  it('should create a blank ecdsa', function() {
+  it('instantiation', function() {
     var ecdsa = new ECDSA();
+    should.exist(ecdsa);
   });
 
   var ecdsa = new ECDSA();
   ecdsa.hashbuf = Hash.sha256(new Buffer('test data'));
-  ecdsa.privkey = new Privkey(BN().fromBuffer(new Buffer('fee0a1f7afebf9d2a5a80c0c98a31c709681cce195cbcd06342b517970c0be1e', 'hex')));
+  ecdsa.privkey = new Privkey(BN.fromBuffer(
+    new Buffer('fee0a1f7afebf9d2a5a80c0c98a31c709681cce195cbcd06342b517970c0be1e', 'hex')
+  ));
   ecdsa.privkey2pubkey();
 
   describe('#set', function() {
-
-    it('should set hashbuf', function() {
+    it('sets hashbuf', function() {
       should.exist(ECDSA().set({
         hashbuf: ecdsa.hashbuf
       }).hashbuf);
     });
-
   });
 
   describe('#calci', function() {
-
-    it('should calculate i', function() {
+    it('calculates i correctly', function() {
       ecdsa.randomK();
       ecdsa.sign();
       ecdsa.calci();
       should.exist(ecdsa.sig.i);
     });
 
-    it('should calulate this known i', function() {
+    it('calulates this known i', function() {
       var hashbuf = Hash.sha256(new Buffer('some data'));
       var r = BN('71706645040721865894779025947914615666559616020894583599959600180037551395766', 10);
       var s = BN('109412465507152403114191008482955798903072313614214706891149785278625167723646', 10);
       var ecdsa = new ECDSA({
-        privkey: Privkey(BN().fromBuffer(Hash.sha256(new Buffer('test')))),
+        privkey: new Privkey(BN.fromBuffer(Hash.sha256(new Buffer('test')))),
         hashbuf: hashbuf,
         sig: new Signature({
           r: r,
@@ -61,12 +61,11 @@ describe("ECDSA", function() {
 
   describe('#fromString', function() {
 
-    it('should to a round trip with to string', function() {
+    it('round trip with fromString', function() {
       var str = ecdsa.toString();
-      var ecdsa2 = new ECDSA();
-      ecdsa2.fromString(str);
-      should.exist(ecdsa.hashbuf);
-      should.exist(ecdsa.privkey);
+      var ecdsa2 = new ECDSA.fromString(str);
+      should.exist(ecdsa2.hashbuf);
+      should.exist(ecdsa2.privkey);
     });
 
   });
@@ -91,60 +90,64 @@ describe("ECDSA", function() {
   });
 
   describe('#deterministicK', function() {
-
     it('should generate the same deterministic k', function() {
       ecdsa.deterministicK();
-      ecdsa.k.toBuffer().toString('hex').should.equal('fcce1de7a9bcd6b2d3defade6afa1913fb9229e3b7ddf4749b55c4848b2a196e');
+      ecdsa.k.toBuffer().toString('hex')
+        .should.equal('fcce1de7a9bcd6b2d3defade6afa1913fb9229e3b7ddf4749b55c4848b2a196e');
     });
-
     it('should generate the same deterministic k if badrs is set', function() {
       ecdsa.deterministicK(0);
-      ecdsa.k.toBuffer().toString('hex').should.equal('fcce1de7a9bcd6b2d3defade6afa1913fb9229e3b7ddf4749b55c4848b2a196e');
+      ecdsa.k.toBuffer().toString('hex')
+        .should.equal('fcce1de7a9bcd6b2d3defade6afa1913fb9229e3b7ddf4749b55c4848b2a196e');
       ecdsa.deterministicK(1);
-      ecdsa.k.toBuffer().toString('hex').should.not.equal('fcce1de7a9bcd6b2d3defade6afa1913fb9229e3b7ddf4749b55c4848b2a196e');
-      ecdsa.k.toBuffer().toString('hex').should.equal('6f4dcca6fa7a137ae9d110311905013b3c053c732ad18611ec2752bb3dcef9d8');
+      ecdsa.k.toBuffer().toString('hex')
+        .should.not.equal('fcce1de7a9bcd6b2d3defade6afa1913fb9229e3b7ddf4749b55c4848b2a196e');
+      ecdsa.k.toBuffer().toString('hex')
+        .should.equal('6f4dcca6fa7a137ae9d110311905013b3c053c732ad18611ec2752bb3dcef9d8');
     });
-
     it('should compute this test vector correctly', function() {
       // test fixture from bitcoinjs
       // https://github.com/bitcoinjs/bitcoinjs-lib/blob/10630873ebaa42381c5871e20336fbfb46564ac8/test/fixtures/ecdsa.json#L6
       var ecdsa = new ECDSA();
       ecdsa.hashbuf = Hash.sha256(new Buffer('Everything should be made as simple as possible, but not simpler.'));
-      ecdsa.privkey = Privkey(BN(1));
+      ecdsa.privkey = new Privkey(BN(1));
       ecdsa.privkey2pubkey();
       ecdsa.deterministicK();
-      ecdsa.k.toBuffer().toString('hex').should.equal('ec633bd56a5774a0940cb97e27a9e4e51dc94af737596a0c5cbb3d30332d92a5');
+      ecdsa.k.toBuffer().toString('hex')
+        .should.equal('ec633bd56a5774a0940cb97e27a9e4e51dc94af737596a0c5cbb3d30332d92a5');
       ecdsa.sign();
-      ecdsa.sig.r.toString().should.equal('23362334225185207751494092901091441011938859014081160902781146257181456271561');
-      ecdsa.sig.s.toString().should.equal('50433721247292933944369538617440297985091596895097604618403996029256432099938');
+      ecdsa.sig.r.toString()
+        .should.equal('23362334225185207751494092901091441011938859014081160902781146257181456271561');
+      ecdsa.sig.s.toString()
+        .should.equal('50433721247292933944369538617440297985091596895097604618403996029256432099938');
     });
-
   });
 
-  describe('#sig2pubkey', function() {
-
+  describe('#toPublicKey', function() {
     it('should calculate the correct public key', function() {
       ecdsa.k = BN('114860389168127852803919605627759231199925249596762615988727970217268189974335', 10);
       ecdsa.sign();
       ecdsa.sig.i = 0;
-      var pubkey = ecdsa.sig2pubkey();
+      var pubkey = ecdsa.toPublicKey();
       pubkey.point.eq(ecdsa.pubkey.point).should.equal(true);
     });
 
     it('should calculate the correct public key for this signature with low s', function() {
       ecdsa.k = BN('114860389168127852803919605627759231199925249596762615988727970217268189974335', 10);
-      ecdsa.sig = Signature.fromString('3045022100ec3cfe0e335791ad278b4ec8eac93d0347a97877bb1d54d35d189e225c15f6650220278cf15b05ce47fb37d2233802899d94c774d5480bba9f0f2d996baa13370c43');
+      ecdsa.sig = Signature.fromString('3045022100ec3cfe0e335791ad278b4ec8eac93d0347' +
+        'a97877bb1d54d35d189e225c15f6650220278cf15b05ce47fb37d2233802899d94c774d5480bba9f0f2d996baa13370c43');
       ecdsa.sig.i = 0;
-      var pubkey = ecdsa.sig2pubkey();
+      var pubkey = ecdsa.toPublicKey();
       pubkey.point.eq(ecdsa.pubkey.point).should.equal(true);
     });
 
     it('should calculate the correct public key for this signature with high s', function() {
       ecdsa.k = BN('114860389168127852803919605627759231199925249596762615988727970217268189974335', 10);
       ecdsa.sign();
-      ecdsa.sig = Signature.fromString('3046022100ec3cfe0e335791ad278b4ec8eac93d0347a97877bb1d54d35d189e225c15f665022100d8730ea4fa31b804c82ddcc7fd766269f33a079ea38e012c9238f2e2bcff34fe');
+      ecdsa.sig = Signature.fromString('3046022100ec3cfe0e335791ad278b4ec8eac93d0347' +
+        'a97877bb1d54d35d189e225c15f665022100d8730ea4fa31b804c82ddcc7fd766269f33a079ea38e012c9238f2e2bcff34fe');
       ecdsa.sig.i = 1;
-      var pubkey = ecdsa.sig2pubkey();
+      var pubkey = ecdsa.toPublicKey();
       pubkey.point.eq(ecdsa.pubkey.point).should.equal(true);
     });
 
@@ -160,18 +163,20 @@ describe("ECDSA", function() {
     it('should return an error if r, s are invalid', function() {
       var ecdsa = new ECDSA();
       ecdsa.hashbuf = Hash.sha256(new Buffer('test'));
-      var pk = Pubkey.fromDER(new Buffer('041ff0fe0f7b15ffaa85ff9f4744d539139c252a49710fb053bb9f2b933173ff9a7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341', 'hex'));
+      var pk = Pubkey.fromDER(new Buffer('041ff0fe0f7b15ffaa85ff9f4744d539139c252a49' +
+        '710fb053bb9f2b933173ff9a7baad41d04514751e6851f5304fd243751703bed21b914f6be218c0fa354a341', 'hex'));
       ecdsa.pubkey = pk;
       ecdsa.sig = new Signature();
       ecdsa.sig.r = BN(0);
       ecdsa.sig.s = BN(0);
-      ecdsa.sigError().should.equal("r and s not in range");
+      ecdsa.sigError().should.equal('r and s not in range');
     });
 
     it('should return an error if the signature is incorrect', function() {
-      ecdsa.sig = new Signature.fromString('3046022100e9915e6236695f093a4128ac2a956c40ed971531de2f4f41ba05fac7e2bd019c02210094e6a4a769cc7f2a8ab3db696c7cd8d56bcdbfff860a8c81de4bc6a798b90827');
+      ecdsa.sig = Signature.fromString('3046022100e9915e6236695f093a4128ac2a956c40' +
+        'ed971531de2f4f41ba05fac7e2bd019c02210094e6a4a769cc7f2a8ab3db696c7cd8d56bcdbfff860a8c81de4bc6a798b90827');
       ecdsa.sig.r = ecdsa.sig.r.add(BN(1));
-      ecdsa.sigError().should.equal("Invalid signature");
+      ecdsa.sigError().should.equal('Invalid signature');
     });
 
   });
@@ -190,9 +195,7 @@ describe("ECDSA", function() {
         privkey: ecdsa.privkey
       });
       ecdsa2.randomK();
-      (function() {
-        ecdsa2.sign();
-      }).should.throw('hashbuf must be a 32 byte buffer');
+      ecdsa2.sign.bind(ecdsa2).should.throw('hashbuf must be a 32 byte buffer');
     });
 
     it('should default to deterministicK', function() {
@@ -210,106 +213,89 @@ describe("ECDSA", function() {
 
   });
 
-  describe('#signRandomK', function() {
-
-    it('should produce a signature, and be different when called twice', function() {
-      ecdsa.signRandomK();
-      should.exist(ecdsa.sig);
-      var ecdsa2 = ECDSA(ecdsa);
-      ecdsa2.signRandomK();
-      ecdsa.sig.toString().should.not.equal(ecdsa2.sig.toString());
-    });
-
-  });
-
   describe('#toString', function() {
-
     it('should convert this to a string', function() {
       var str = ecdsa.toString();
       (typeof str === 'string').should.equal(true);
     });
-
   });
 
-  describe('#verify', function() {
-
-    it('should verify a signature that was just signed', function() {
-      ecdsa.sig = new Signature.fromString('3046022100e9915e6236695f093a4128ac2a956c40ed971531de2f4f41ba05fac7e2bd019c02210094e6a4a769cc7f2a8ab3db696c7cd8d56bcdbfff860a8c81de4bc6a798b90827');
-      ecdsa.verify().verified.should.equal(true);
-    });
-
-    it('should verify this known good signature', function() {
-      ecdsa.signRandomK();
-      ecdsa.verify().verified.should.equal(true);
-    });
-
-  });
-
-  describe('@sign', function() {
-
-    it('should produce a signature', function() {
-      var sig = ECDSA.sign(ecdsa.hashbuf, ecdsa.privkey);
-      (sig instanceof Signature).should.equal(true);
-    });
-
-  });
-
-  describe('@verify', function() {
-
-    it('should verify a valid signature, and unverify an invalid signature', function() {
-      var sig = ECDSA.sign(ecdsa.hashbuf, ecdsa.privkey);
-      ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey).should.equal(true);
-      var fakesig = Signature(sig.r.add(1), sig.s);
-      ECDSA.verify(ecdsa.hashbuf, fakesig, ecdsa.pubkey).should.equal(false);
-    });
-
-    it('should work with big and little endian', function() {
-      var sig = ECDSA.sign(ecdsa.hashbuf, ecdsa.privkey, 'big');
-      ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey, 'big').should.equal(true);
-      ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey, 'little').should.equal(false);
-      sig = ECDSA.sign(ecdsa.hashbuf, ecdsa.privkey, 'little');
-      ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey, 'big').should.equal(false);
-      ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey, 'little').should.equal(true);
-    });
-
-  });
-
-  describe('vectors', function() {
-
-    vectors.valid.forEach(function(obj, i) {
-      it('should validate valid vector ' + i, function() {
-        var ecdsa = ECDSA().set({
-          privkey: Privkey(BN().fromBuffer(new Buffer(obj.d, 'hex'))),
-          k: BN().fromBuffer(new Buffer(obj.k, 'hex')),
-          hashbuf: Hash.sha256(new Buffer(obj.message)),
-          sig: Signature().set({
-            r: BN(obj.signature.r),
-            s: BN(obj.signature.s),
-            i: obj.i
-          })
-        });
+  describe('signing and verification', function() {
+    describe('@sign', function() {
+      it('should produce a signature', function() {
+        var sig = ECDSA.sign(ecdsa.hashbuf, ecdsa.privkey);
+        (sig instanceof Signature).should.equal(true);
+      });
+      it('should produce a signature, and be different when called twice', function() {
+        ecdsa.signRandomK();
+        should.exist(ecdsa.sig);
         var ecdsa2 = ECDSA(ecdsa);
-        ecdsa2.k = undefined;
-        ecdsa2.sign();
-        ecdsa2.calci();
-        ecdsa2.k.toString().should.equal(ecdsa.k.toString());
-        ecdsa2.sig.toString().should.equal(ecdsa.sig.toString());
-        ecdsa2.sig.i.should.equal(ecdsa.sig.i);
+        ecdsa2.signRandomK();
+        ecdsa.sig.toString().should.not.equal(ecdsa2.sig.toString());
+      });
+    });
+
+    describe('#verify', function() {
+      it('should verify a signature that was just signed', function() {
+        ecdsa.sig = Signature.fromString('3046022100e9915e6236695f093a4128ac2a956c' +
+          '40ed971531de2f4f41ba05fac7e2bd019c02210094e6a4a769cc7f2a8ab3db696c7cd8d56bcdbfff860a8c81de4bc6a798b90827');
         ecdsa.verify().verified.should.equal(true);
       });
-    });
-
-    vectors.invalid.sigError.forEach(function(obj, i) {
-      it('should validate invalid.sigError vector ' + i + ': ' + obj.description, function() {
-        var ecdsa = ECDSA().set({
-          pubkey: Pubkey.fromPoint(point.fromX(true, 1)),
-          sig: Signature(BN(obj.signature.r), BN(obj.signature.s)),
-          hashbuf: Hash.sha256(new Buffer(obj.message))
-        });
-        ecdsa.sigError().should.equal(obj.exception);
+      it('should verify this known good signature', function() {
+        ecdsa.signRandomK();
+        ecdsa.verify().verified.should.equal(true);
+      });
+      it('should verify a valid signature, and unverify an invalid signature', function() {
+        var sig = ECDSA.sign(ecdsa.hashbuf, ecdsa.privkey);
+        ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey).should.equal(true);
+        var fakesig = new Signature(sig.r.add(1), sig.s);
+        ECDSA.verify(ecdsa.hashbuf, fakesig, ecdsa.pubkey).should.equal(false);
+      });
+      it('should work with big and little endian', function() {
+        var sig = ECDSA.sign(ecdsa.hashbuf, ecdsa.privkey, 'big');
+        ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey, 'big').should.equal(true);
+        ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey, 'little').should.equal(false);
+        sig = ECDSA.sign(ecdsa.hashbuf, ecdsa.privkey, 'little');
+        ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey, 'big').should.equal(false);
+        ECDSA.verify(ecdsa.hashbuf, sig, ecdsa.pubkey, 'little').should.equal(true);
       });
     });
 
-  });
+    describe('vectors', function() {
 
+      vectors.valid.forEach(function(obj, i) {
+        it('should validate valid vector ' + i, function() {
+          var ecdsa = ECDSA().set({
+            privkey: new Privkey(BN.fromBuffer(new Buffer(obj.d, 'hex'))),
+            k: BN.fromBuffer(new Buffer(obj.k, 'hex')),
+            hashbuf: Hash.sha256(new Buffer(obj.message)),
+            sig: new Signature().set({
+              r: BN(obj.signature.r),
+              s: BN(obj.signature.s),
+              i: obj.i
+            })
+          });
+          var ecdsa2 = ECDSA(ecdsa);
+          ecdsa2.k = undefined;
+          ecdsa2.sign();
+          ecdsa2.calci();
+          ecdsa2.k.toString().should.equal(ecdsa.k.toString());
+          ecdsa2.sig.toString().should.equal(ecdsa.sig.toString());
+          ecdsa2.sig.i.should.equal(ecdsa.sig.i);
+          ecdsa.verify().verified.should.equal(true);
+        });
+      });
+
+      vectors.invalid.sigError.forEach(function(obj, i) {
+        it('should validate invalid.sigError vector ' + i + ': ' + obj.description, function() {
+          var ecdsa = ECDSA().set({
+            pubkey: Pubkey.fromPoint(point.fromX(true, 1)),
+            sig: new Signature(BN(obj.signature.r), BN(obj.signature.s)),
+            hashbuf: Hash.sha256(new Buffer(obj.message))
+          });
+          ecdsa.sigError().should.equal(obj.exception);
+        });
+      });
+    });
+  });
 });
diff --git a/test/crypto/hash.js b/test/crypto/hash.js
index 7509d924e..c079feee2 100644
--- a/test/crypto/hash.js
+++ b/test/crypto/hash.js
@@ -10,121 +10,125 @@ describe('Hash', function() {
 
   describe('@sha1', function() {
 
-    it('should calculate the hash of this buffer correctly', function() {
+    it('calculates the hash of this buffer correctly', function() {
       var hash = Hash.sha1(buf);
       hash.toString('hex').should.equal('de69b8a4a5604d0486e6420db81e39eb464a17b2');
       hash = Hash.sha1(new Buffer(0));
       hash.toString('hex').should.equal('da39a3ee5e6b4b0d3255bfef95601890afd80709');
     });
 
-    it('should throw an error when the input is not a buffer', function() {
-      (function() {
-        Hash.sha1(str);
-      }).should.throw('Invalid Argument');
+    it('throws an error when the input is not a buffer', function() {
+      Hash.sha1.bind(Hash, str).should.throw('Invalid Argument');
     });
 
   });
 
   describe('#sha256', function() {
 
-    it('should calculate the hash of this buffer correctly', function() {
+    it('calculates the hash of this buffer correctly', function() {
       var hash = Hash.sha256(buf);
       hash.toString('hex').should.equal('6f2c7b22fd1626998287b3636089087961091de80311b9279c4033ec678a83e8');
     });
 
-    it('should throw an error when the input is not a buffer', function() {
-      (function() {
-        Hash.sha256(str);
-      }).should.throw('Invalid Argument');
+    it('fails when the input is not a buffer', function() {
+      Hash.sha256.bind(Hash, str).should.throw('Invalid Argument');
     });
 
   });
 
   describe('#sha256hmac', function() {
 
-    it('should compute this known empty test vector correctly', function() {
-      var key = new Buffer('');
+    it('computes this known big key correctly', function() {
+      var key = new Buffer('b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad' +
+        'b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad' +
+        'b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad' +
+        'b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad');
       var data = new Buffer('');
-      Hash.sha256hmac(data, key).toString('hex').should.equal('b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad');
+      Hash.sha256hmac(data, key).toString('hex')
+        .should.equal('fb1f87218671f1c0c4593a88498e02b6dfe8afd814c1729e89a1f1f6600faa23');
     });
 
-    it('should compute this known non-empty test vector correctly', function() {
+    it('computes this known empty test vector correctly', function() {
+      var key = new Buffer('');
+      var data = new Buffer('');
+      Hash.sha256hmac(data, key).toString('hex')
+        .should.equal('b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad');
+    });
+
+    it('computes this known non-empty test vector correctly', function() {
       var key = new Buffer('key');
       var data = new Buffer('The quick brown fox jumps over the lazy dog');
-      Hash.sha256hmac(data, key).toString('hex').should.equal('f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8');
+      Hash.sha256hmac(data, key).toString('hex')
+        .should.equal('f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8');
     });
 
   });
 
   describe('#sha256sha256', function() {
 
-    it('should calculate the hash of this buffer correctly', function() {
+    it('calculates the hash of this buffer correctly', function() {
       var hash = Hash.sha256sha256(buf);
       hash.toString('hex').should.equal('be586c8b20dee549bdd66018c7a79e2b67bb88b7c7d428fa4c970976d2bec5ba');
     });
 
-    it('should throw an error when the input is not a buffer', function() {
-      (function() {
-        Hash.sha256sha256(str);
-      }).should.throw('Invalid Argument');
+    it('fails when the input is not a buffer', function() {
+      Hash.sha256sha256.bind(Hash, str).should.throw('Invalid Argument');
     });
 
   });
 
   describe('#sha256ripemd160', function() {
 
-    it('should calculate the hash of this buffer correctly', function() {
+    it('calculates the hash of this buffer correctly', function() {
       var hash = Hash.sha256ripemd160(buf);
       hash.toString('hex').should.equal('7322e2bd8535e476c092934e16a6169ca9b707ec');
     });
 
-    it('should throw an error when the input is not a buffer', function() {
-      (function() {
-        Hash.sha256ripemd160(str);
-      }).should.throw('Invalid Argument');
+    it('fails when the input is not a buffer', function() {
+      Hash.sha256ripemd160.bind(Hash, str).should.throw('Invalid Argument');
     });
 
   });
 
   describe('#ripemd160', function() {
 
-    it('should calculate the hash of this buffer correctly', function() {
+    it('calculates the hash of this buffer correctly', function() {
       var hash = Hash.ripemd160(buf);
       hash.toString('hex').should.equal('fa0f4565ff776fee0034c713cbf48b5ec06b7f5c');
     });
 
-    it('should throw an error when the input is not a buffer', function() {
-      (function() {
-        Hash.ripemd160(str);
-      }).should.throw('Invalid Argument');
+    it('fails when the input is not a buffer', function() {
+      Hash.ripemd160.bind(Hash, str).should.throw('Invalid Argument');
     });
 
   });
 
   describe('#sha512', function() {
 
-    it('should calculate the hash of this buffer correctly', function() {
+    it('calculates the hash of this buffer correctly', function() {
       var hash = Hash.sha512(buf);
-      hash.toString('hex').should.equal('c0530aa32048f4904ae162bc14b9eb535eab6c465e960130005feddb71613e7d62aea75f7d3333ba06e805fc8e45681454524e3f8050969fe5a5f7f2392e31d0');
+      hash.toString('hex')
+        .should.equal('c0530aa32048f4904ae162bc14b9eb535eab6c465e960130005fedd' +
+          'b71613e7d62aea75f7d3333ba06e805fc8e45681454524e3f8050969fe5a5f7f2392e31d0');
     });
 
-    it('should throw an error when the input is not a buffer', function() {
-      (function() {
-        Hash.sha512(str);
-      }).should.throw('Invalid Argument');
+    it('fails when the input is not a buffer', function() {
+      Hash.sha512.bind(Hash, str).should.throw('Invalid Argument');
     });
 
   });
 
   describe('#sha512hmac', function() {
 
-    it('should calculate this known empty test vector correctly', function() {
-      var hex = 'b936cee86c9f87aa5d3c6f2e84cb5a4239a5fe50480a6ec66b70ab5b1f4ac6730c6c515421b327ec1d69402e53dfb49ad7381eb067b338fd7b0cb22247225d47';
+    it('calculates this known empty test vector correctly', function() {
+      var hex = 'b936cee86c9f87aa5d3c6f2e84cb5a4239a5fe50480a6ec66b70ab5b1f4a' +
+        'c6730c6c515421b327ec1d69402e53dfb49ad7381eb067b338fd7b0cb22247225d47';
       Hash.sha512hmac(new Buffer([]), new Buffer([])).toString('hex').should.equal(hex);
     });
 
-    it('should calculate this known non-empty test vector correctly', function() {
-      var hex = 'c40bd7c15aa493b309c940e08a73ffbd28b2e4cb729eb94480d727e4df577b13cc403a78e6150d83595f3b17c4cc331f12ca5952691de3735a63c1d4c69a2bac';
+    it('calculates this known non-empty test vector correctly', function() {
+      var hex = 'c40bd7c15aa493b309c940e08a73ffbd28b2e4cb729eb94480d727e4df577' +
+        'b13cc403a78e6150d83595f3b17c4cc331f12ca5952691de3735a63c1d4c69a2bac';
       var data = new Buffer('test1');
       var key = new Buffer('test2');
       Hash.sha512hmac(data, key).toString('hex').should.equal(hex);
diff --git a/test/crypto/random.js b/test/crypto/random.js
index 4a7c03939..cf08bc222 100644
--- a/test/crypto/random.js
+++ b/test/crypto/random.js
@@ -21,11 +21,14 @@ describe('Random', function() {
 
     it('should generate 100 8 byte buffers in a row that are not equal', function() {
       var hexs = [];
-      for (var i = 0; i < 100; i++)
+      for (var i = 0; i < 100; i++) {
         hexs[i] = Random.getRandomBuffer(8).toString('hex');
-      for (i = 0; i < 100; i++)
-        for (var j = i + 1; j < 100; j++)
+      }
+      for (i = 0; i < 100; i++) {
+        for (var j = i + 1; j < 100; j++) {
           hexs[i].should.not.equal(hexs[j]);
+        }
+      }
     });
 
   });
diff --git a/test/script/interpreter.js b/test/script/interpreter.js
index 7be035e3a..46bda124c 100644
--- a/test/script/interpreter.js
+++ b/test/script/interpreter.js
@@ -89,7 +89,7 @@ describe('Interpreter', function() {
       })).should.equal(true);
 
       var buf = new Buffer('00', 'hex');
-      var bool = BN().fromSM(buf, {
+      var bool = BN.fromSM(buf, {
         endian: 'little'
       }).cmp(0) !== 0;
       Interpreter.castToBool(buf).should.equal(bool);
@@ -201,7 +201,7 @@ describe('Interpreter', function() {
 
     var hashbuf = new Buffer(32);
     hashbuf.fill(0);
-    var credtx = Transaction();
+    var credtx = new Transaction();
     credtx.uncheckedAddInput(new Transaction.Input({
       prevTxId: '0000000000000000000000000000000000000000000000000000000000000000',
       outputIndex: 0xffffffff,
@@ -214,7 +214,7 @@ describe('Interpreter', function() {
     }));
     var idbuf = credtx.id;
 
-    var spendtx = Transaction();
+    var spendtx = new Transaction();
     spendtx.uncheckedAddInput(new Transaction.Input({
       prevTxId: idbuf.toString('hex'),
       outputIndex: 0,
@@ -222,11 +222,11 @@ describe('Interpreter', function() {
       script: scriptSig
     }));
     spendtx.addOutput(new Transaction.Output({
-      script: Script(),
+      script: new Script(),
       satoshis: 0
     }));
 
-    var interp = Interpreter();
+    var interp = new Interpreter();
     var verified = interp.verify(scriptSig, scriptPubkey, spendtx, 0, flags);
     verified.should.equal(expected);
   };
@@ -275,7 +275,7 @@ describe('Interpreter', function() {
             map[txid + ':' + txoutnum] = Script.fromBitcoindString(scriptPubKeyStr);
           });
 
-          var tx = Transaction(txhex);
+          var tx = new Transaction(txhex);
           var allInputsVerified = true;
           tx.inputs.forEach(function(txin, j) {
             var scriptSig = txin.script;
@@ -284,7 +284,7 @@ describe('Interpreter', function() {
             var scriptPubkey = map[txidhex + ':' + txoutnum];
             should.exist(scriptPubkey);
             should.exist(scriptSig);
-            var interp = Interpreter();
+            var interp = new Interpreter();
             var verified = interp.verify(scriptSig, scriptPubkey, tx, j, flags);
             if (!verified) {
               allInputsVerified = false;