diff --git a/README.md b/README.md
index ae980034..f4d25a69 100644
--- a/README.md
+++ b/README.md
@@ -521,13 +521,13 @@ Scripts are array-like objects with some helper functions.
 ``` js
 var bcoin = require('bcoin');
 var assert = require('assert');
-var bn = bcoin.bn;
+var BN = bcoin.bn;
 var opcodes = bcoin.script.opcodes;
 
 var output = new bcoin.script();
 output.push(opcodes.OP_DROP);
 output.push(opcodes.OP_ADD);
-output.push(new bn(7));
+output.push(new BN(7));
 output.push(opcodes.OP_NUMEQUAL);
 // Compile the script to its binary representation
 // (you must do this if you change something!).
@@ -536,8 +536,8 @@ assert(output.getSmall(2) === 7); // compiled as OP_7
 
 var input = new bcoin.script();
 input.set(0, 'hello world'); // add some metadata
-input.push(new bn(2));
-input.push(new bn(5));
+input.push(new BN(2));
+input.push(new BN(5));
 input.push(input.shift());
 assert(input.getString(2) === 'hello world');
 input.compile();
@@ -558,8 +558,8 @@ Stack object (an array-like object containing Buffers).
 
 ``` js
 var witness = new bcoin.witness();
-witness.push(new bn(2));
-witness.push(new bn(5));
+witness.push(new BN(2));
+witness.push(new BN(5));
 witness.push('hello world');
 
 var stack = witness.toStack();
diff --git a/bench/coin.js b/bench/coin.js
index f2305104..dcd128be 100644
--- a/bench/coin.js
+++ b/bench/coin.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var constants = require('../lib/protocol/constants');
 var utils = require('../lib/utils/utils');
 var assert = require('assert');
diff --git a/bench/mnemonic.js b/bench/mnemonic.js
index 6d0ee898..35b6a4cc 100644
--- a/bench/mnemonic.js
+++ b/bench/mnemonic.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var constants = bcoin.constants;
 var utils = bcoin.utils;
diff --git a/bench/tx.js b/bench/tx.js
index d2333af4..cd2f3720 100644
--- a/bench/tx.js
+++ b/bench/tx.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var constants = bcoin.constants;
 var utils = bcoin.utils;
diff --git a/bench/walletdb.js b/bench/walletdb.js
index 07b3ed28..a067fe85 100644
--- a/bench/walletdb.js
+++ b/bench/walletdb.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var constants = bcoin.constants;
 var utils = bcoin.utils;
@@ -74,7 +74,7 @@ var runBench = co(function* runBench() {
 
   // TX
   jobs = [];
-  nonce = new bn(0);
+  nonce = new BN(0);
   for (i = 0; i < 10000; i++) {
     tx = bcoin.mtx()
       .addOutput(addrs[(i + 0) % addrs.length], 50460)
diff --git a/lib/bip70/pk.js b/lib/bip70/pk.js
index 0890f955..241e0359 100644
--- a/lib/bip70/pk.js
+++ b/lib/bip70/pk.js
@@ -6,7 +6,7 @@
 
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var asn1 = require('./asn1');
 var elliptic = require('elliptic');
 var crypto = require('../crypto/crypto');
@@ -43,8 +43,8 @@ rsa.verify = function verify(hashAlg, msg, sig, key) {
   var prefix = rsa.prefixes[hashAlg];
   var len = prefix.length + hash.length;
   var pub = asn1.parseRSAPublic(key);
-  var N = new bn(pub.modulus);
-  var e = new bn(pub.publicExponent);
+  var N = new BN(pub.modulus);
+  var e = new BN(pub.publicExponent);
   var k = Math.ceil(N.bitLength() / 8);
   var m, em, ok, i;
 
@@ -71,8 +71,8 @@ rsa.sign = function sign(hashAlg, msg, key) {
   var prefix = rsa.prefixes[hashAlg];
   var len = prefix.length + hash.length;
   var priv = asn1.parseRSAPrivate(key);
-  var N = new bn(priv.modulus);
-  var D = new bn(priv.privateExponent);
+  var N = new BN(priv.modulus);
+  var D = new BN(priv.privateExponent);
   var k = Math.ceil(N.bitLength() / 8);
   var i, em;
 
@@ -93,7 +93,7 @@ rsa.sign = function sign(hashAlg, msg, key) {
 };
 
 rsa.decrypt = function decrypt(N, D, m) {
-  var c = new bn(m);
+  var c = new BN(m);
 
   if (c.cmp(N) > 0)
     throw new Error('Cannot decrypt.');
@@ -106,7 +106,7 @@ rsa.decrypt = function decrypt(N, D, m) {
 };
 
 rsa.encrypt = function encrypt(N, e, m) {
-  return new bn(m)
+  return new BN(m)
     .toRed(bn.red(N))
     .redPow(e)
     .fromRed()
diff --git a/lib/chain/chainentry.js b/lib/chain/chainentry.js
index 455955a2..bc76349d 100644
--- a/lib/chain/chainentry.js
+++ b/lib/chain/chainentry.js
@@ -7,7 +7,7 @@
 
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var Network = require('../protocol/network');
 var constants = require('../protocol/constants');
 var utils = require('../utils/utils');
@@ -81,7 +81,7 @@ ChainEntry.prototype.fromOptions = function fromOptions(options, prev) {
   assert(utils.isNumber(options.ts));
   assert(utils.isNumber(options.bits));
   assert(utils.isNumber(options.nonce));
-  assert(!options.chainwork || bn.isBN(options.chainwork));
+  assert(!options.chainwork || BN.isBN(options.chainwork));
 
   this.hash = options.hash;
   this.version = options.version;
@@ -116,7 +116,7 @@ ChainEntry.fromOptions = function fromOptions(chain, options, prev) {
  * @const {BN}
  */
 
-ChainEntry.MAX_CHAINWORK = new bn(1).ushln(256);
+ChainEntry.MAX_CHAINWORK = new BN(1).ushln(256);
 
 /**
  * Calculate the proof: (1 << 256) / (target + 1)
@@ -126,7 +126,7 @@ ChainEntry.MAX_CHAINWORK = new bn(1).ushln(256);
 ChainEntry.prototype.getProof = function getProof() {
   var target = utils.fromCompact(this.bits);
   if (target.isNeg() || target.cmpn(0) === 0)
-    return new bn(0);
+    return new BN(0);
   return ChainEntry.MAX_CHAINWORK.div(target.iaddn(1));
 };
 
@@ -526,7 +526,7 @@ ChainEntry.prototype.fromRaw = function fromRaw(data) {
   this.bits = p.readU32();
   this.nonce = p.readU32();
   this.height = p.readU32();
-  this.chainwork = new bn(p.readBytes(32), 'le');
+  this.chainwork = new BN(p.readBytes(32), 'le');
 
   return this;
 };
@@ -587,7 +587,7 @@ ChainEntry.prototype.fromJSON = function fromJSON(json) {
   this.bits = json.bits;
   this.nonce = json.nonce;
   this.height = json.height;
-  this.chainwork = new bn(json.chainwork, 10);
+  this.chainwork = new BN(json.chainwork, 10);
 
   return this;
 };
diff --git a/lib/crypto/ec.js b/lib/crypto/ec.js
index 2727b303..98f4c32d 100644
--- a/lib/crypto/ec.js
+++ b/lib/crypto/ec.js
@@ -8,7 +8,7 @@
 'use strict';
 
 var elliptic = require('elliptic');
-var bn = require('bn.js');
+var BN = require('bn.js');
 var utils = require('../utils/utils');
 var crypto = require('./crypto');
 var assert = require('assert');
@@ -139,8 +139,8 @@ ec.privateKeyTweakAdd = function privateKeyTweakAdd(privateKey, tweak) {
   if (secp256k1)
     return secp256k1.privateKeyTweakAdd(privateKey, tweak);
 
-  key = new bn(tweak)
-    .add(new bn(privateKey))
+  key = new BN(tweak)
+    .add(new BN(privateKey))
     .mod(ec.curve.n)
     .toArrayLike(Buffer, 'be', 32);
 
@@ -165,7 +165,7 @@ ec.publicKeyTweakAdd = function publicKeyTweakAdd(publicKey, tweak, compressed)
     return secp256k1.publicKeyTweakAdd(publicKey, tweak, compressed);
 
   point = ec.curve.decodePoint(publicKey);
-  point = ec.curve.g.mul(new bn(tweak)).add(point);
+  point = ec.curve.g.mul(new BN(tweak)).add(point);
   key = new Buffer(point.encode('array', compressed !== false));
 
   if (!ec.publicKeyVerify(key))
@@ -335,7 +335,7 @@ ec.privateKeyVerify = function privateKeyVerify(key) {
   if (key.length !== 32)
     return false;
 
-  key = new bn(key);
+  key = new BN(key);
 
   return key.cmpn(0) !== 0 && key.cmp(ec.curve.n) < 0;
 };
@@ -411,8 +411,8 @@ ec.toDER = function toDER(sig) {
     return secp256k1.signatureExport(sig);
 
   out = new ec.signature({
-    r: new bn(sig.slice(0, 32), 'be'),
-    s: new bn(sig.slice(32, 64), 'be')
+    r: new BN(sig.slice(0, 32), 'be'),
+    s: new BN(sig.slice(32, 64), 'be')
   });
 
   return new Buffer(out.toDER());
diff --git a/lib/crypto/schnorr.js b/lib/crypto/schnorr.js
index a91cf120..8814cc0b 100644
--- a/lib/crypto/schnorr.js
+++ b/lib/crypto/schnorr.js
@@ -6,7 +6,7 @@
 
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var elliptic = require('elliptic');
 var Signature = require('elliptic/lib/elliptic/ec/signature');
 var hmacDRBG = require('elliptic/lib/elliptic/hmac-drbg');
@@ -40,7 +40,7 @@ schnorr.hash = function _hash(msg, r, hash) {
   msg.copy(B, 32);
   H = hash(B);
 
-  return new bn(H);
+  return new BN(H);
 };
 
 /**
@@ -99,7 +99,7 @@ schnorr._sign = function _sign(msg, prv, k, hash, pubnonce) {
  */
 
 schnorr.sign = function sign(msg, key, hash, pubnonce) {
-  var prv = new bn(key);
+  var prv = new BN(key);
   var k, sig;
 
   if (prv.cmpn(0) === 0)
@@ -109,7 +109,7 @@ schnorr.sign = function sign(msg, key, hash, pubnonce) {
     throw new Error('Bad private key.');
 
   while (!sig) {
-    k = new bn(crypto.randomBytes(32));
+    k = new BN(crypto.randomBytes(32));
     sig = schnorr._sign(msg, prv, k, hash, pubnonce);
   }
 
@@ -213,7 +213,7 @@ schnorr.recover = function recover(signature, msg, hash) {
  */
 
 schnorr.combineSigs = function combineSigs(sigs) {
-  var s = new bn(0);
+  var s = new BN(0);
   var i, r, sig, last;
 
   for (i = 0; i < sigs.length; i++) {
@@ -279,7 +279,7 @@ schnorr.combineKeys = function combineKeys(keys) {
  */
 
 schnorr.partialSign = function partialSign(msg, priv, privnonce, pubs, hash) {
-  var prv = new bn(priv);
+  var prv = new BN(priv);
   var sig;
 
   if (prv.cmpn(0) === 0)
@@ -288,7 +288,7 @@ schnorr.partialSign = function partialSign(msg, priv, privnonce, pubs, hash) {
   if (prv.cmp(curve.n) >= 0)
     throw new Error('Bad private key.');
 
-  sig = schnorr._sign(msg, prv, new bn(privnonce), hash, pubs);
+  sig = schnorr._sign(msg, prv, new BN(privnonce), hash, pubs);
 
   if (!sig)
     throw new Error('Bad K value.');
@@ -358,7 +358,7 @@ schnorr.nonce = function nonce(msg, priv, data, ncb) {
 
   pubnonce = ncb(msg, priv, data);
 
-  return new bn(pubnonce);
+  return new BN(pubnonce);
 };
 
 /**
diff --git a/lib/miner/minerblock.js b/lib/miner/minerblock.js
index baf85ae8..8ff2e0db 100644
--- a/lib/miner/minerblock.js
+++ b/lib/miner/minerblock.js
@@ -13,7 +13,7 @@ var crypto = require('../crypto/crypto');
 var assert = require('assert');
 var constants = require('../protocol/constants');
 var Network = require('../protocol/network');
-var bn = require('bn.js');
+var BN = require('bn.js');
 var EventEmitter = require('events').EventEmitter;
 var TX = require('../primitives/tx');
 var Block = require('../primitives/block');
@@ -54,7 +54,7 @@ function MinerBlock(options) {
   this.bits = options.bits;
   this.target = utils.fromCompact(this.bits).toArrayLike(Buffer, 'le', 32);
   this.flags = options.flags;
-  this.extraNonce = new bn(0);
+  this.extraNonce = new BN(0);
   this.iterations = 0;
   this.coinbaseFlags = options.coinbaseFlags;
   this.witness = options.witness;
@@ -106,7 +106,7 @@ MinerBlock.prototype._init = function _init() {
   input = new Input();
 
   // Height (required in v2+ blocks)
-  input.script.set(0, new bn(this.height));
+  input.script.set(0, new BN(this.height));
 
   // extraNonce - incremented when
   // the nonce overflows.
diff --git a/lib/net/packets.js b/lib/net/packets.js
index 2bbd3c33..c2564e28 100644
--- a/lib/net/packets.js
+++ b/lib/net/packets.js
@@ -7,7 +7,7 @@
 
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var constants = require('../protocol/constants');
 var utils = require('../utils/utils');
 var assert = require('assert');
@@ -122,7 +122,7 @@ function VersionPacket(options) {
   this.ts = time.now();
   this.recv = new NetworkAddress();
   this.from = new NetworkAddress();
-  this.nonce = new bn(0);
+  this.nonce = new BN(0);
   this.agent = constants.USER_AGENT;
   this.height = 0;
   this.relay = true;
@@ -440,7 +440,7 @@ function PongPacket(nonce) {
 
   Packet.call(this);
 
-  this.nonce = nonce || new bn(0);
+  this.nonce = nonce || new BN(0);
 }
 
 utils.inherits(PongPacket, Packet);
diff --git a/lib/protocol/networks.js b/lib/protocol/networks.js
index 67660013..c3e8f713 100644
--- a/lib/protocol/networks.js
+++ b/lib/protocol/networks.js
@@ -7,7 +7,7 @@
 
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 
 /**
  * @module network
@@ -167,7 +167,7 @@ main.pow = {
    * @const {Buffer}
    */
 
-  limit: new bn(
+  limit: new BN(
     '00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
     'hex'
   ),
@@ -498,7 +498,7 @@ testnet.genesisBlock =
   + 'ac00000000';
 
 testnet.pow = {
-  limit: new bn(
+  limit: new BN(
     '00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
     'hex'
   ),
@@ -641,7 +641,7 @@ regtest.genesisBlock =
   + 'ac00000000';
 
 regtest.pow = {
-  limit: new bn(
+  limit: new BN(
     '7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
     'hex'
   ),
@@ -781,7 +781,7 @@ segnet3.genesisBlock =
   + 'ac00000000';
 
 segnet3.pow = {
-  limit: new bn(
+  limit: new BN(
     '00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
     'hex'
   ),
@@ -897,7 +897,7 @@ segnet4.genesisBlock =
 
 segnet4.pow = {
   // 512x lower min difficulty than mainnet
-  limit: new bn(
+  limit: new BN(
     '000001ffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
     'hex'
   ),
@@ -1034,7 +1034,7 @@ simnet.genesisBlock =
   + 'ac00000000';
 
 simnet.pow = {
-  limit: new bn(
+  limit: new BN(
     // High target of 0x207fffff (545259519)
     '7fffff0000000000000000000000000000000000000000000000000000000000',
     'hex'
diff --git a/lib/script/opcode.js b/lib/script/opcode.js
index 4db6c9a5..b3ce76e7 100644
--- a/lib/script/opcode.js
+++ b/lib/script/opcode.js
@@ -9,7 +9,7 @@
 
 module.exports = Opcode;
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var constants = require('../protocol/constants');
 var utils = require('../utils/utils');
 var Script = require('./script');
@@ -153,7 +153,7 @@ Opcode.from = function from(data) {
   if (typeof data === 'string')
     return Opcode.fromString(data, 'utf8');
 
-  if (bn.isBN(data))
+  if (BN.isBN(data))
     return Opcode.fromNumber(data);
 
   assert(false, 'Bad data for opcode.');
diff --git a/lib/script/script.js b/lib/script/script.js
index 0fbb1505..54341c48 100644
--- a/lib/script/script.js
+++ b/lib/script/script.js
@@ -9,7 +9,7 @@
 
 module.exports = Script;
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var constants = require('../protocol/constants');
 var utils = require('../utils/utils');
 var crypto = require('../crypto/crypto');
@@ -777,11 +777,11 @@ Script.prototype.execute = function execute(stack, flags, tx, index, version) {
             break;
           case opcodes.OP_NOT:
             num = num.cmpn(0) === 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_0NOTEQUAL:
             num = num.cmpn(0) !== 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           default:
             assert(false, 'Fatal script error.');
@@ -847,39 +847,39 @@ Script.prototype.execute = function execute(stack, flags, tx, index, version) {
             break;
           case opcodes.OP_BOOLAND:
             num = n1.cmpn(0) !== 0 && n2.cmpn(0) !== 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_BOOLOR:
             num = n1.cmpn(0) !== 0 || n2.cmpn(0) !== 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_NUMEQUAL:
             num = n1.cmp(n2) === 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_NUMEQUALVERIFY:
             num = n1.cmp(n2) === 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_NUMNOTEQUAL:
             num = n1.cmp(n2) !== 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_LESSTHAN:
             num = n1.cmp(n2) < 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_GREATERTHAN:
             num = n1.cmp(n2) > 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_LESSTHANOREQUAL:
             num = n1.cmp(n2) <= 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_GREATERTHANOREQUAL:
             num = n1.cmp(n2) >= 0;
-            num = new bn(num ? 1 : 0);
+            num = new BN(num ? 1 : 0);
             break;
           case opcodes.OP_MIN:
             num = n1.cmp(n2) < 0 ? n1 : n2;
@@ -1364,9 +1364,9 @@ Script.num = function num(value, flags, size) {
   }
 
   if (value.length === 0)
-    return new bn(0);
+    return new BN(0);
 
-  result = new bn(value, 'le');
+  result = new BN(value, 'le');
 
   // If the input vector's most significant byte is
   // 0x80, remove it from the result's msb and return
@@ -1386,8 +1386,8 @@ Script.num = function num(value, flags, size) {
  * @example
  * assert.deepEqual(Script.array(0), new Buffer(0));
  * assert.deepEqual(Script.array(0xffee), new Buffer('eeff00', 'hex'));
- * assert.deepEqual(Script.array(new bn(0xffee)), new Buffer('eeff00', 'hex'));
- * assert.deepEqual(Script.array(new bn(0x1e).ineg()), new Buffer('9e', 'hex'));
+ * assert.deepEqual(Script.array(new BN(0xffee)), new Buffer('eeff00', 'hex'));
+ * assert.deepEqual(Script.array(new BN(0x1e).ineg()), new Buffer('9e', 'hex'));
  * @param {Number|BN} value
  * @returns {Buffer}
  */
@@ -1396,9 +1396,9 @@ Script.array = function(value) {
   var neg, result;
 
   if (utils.isNumber(value))
-    value = new bn(value);
+    value = new BN(value);
 
-  assert(bn.isBN(value));
+  assert(BN.isBN(value));
 
   if (value.cmpn(0) === 0)
     return STACK_FALSE;
@@ -2623,7 +2623,7 @@ Script.prototype.getNumber = function getNumber(i) {
   var op = this.code[i];
 
   if (small !== -1)
-    return new bn(small);
+    return new BN(small);
 
   if (!op || !op.data || op.data.length > 5)
     return;
@@ -3234,7 +3234,7 @@ Script.prototype.fromString = function fromString(code) {
         continue;
       }
       if (/^-?\d+$/.test(op)) {
-        op = new bn(op, 10);
+        op = new BN(op, 10);
         op = Opcode.fromNumber(op);
         p.writeBytes(op.toRaw());
         continue;
diff --git a/lib/script/witness.js b/lib/script/witness.js
index 8b096ef8..2ca39de0 100644
--- a/lib/script/witness.js
+++ b/lib/script/witness.js
@@ -9,7 +9,7 @@
 
 module.exports = Witness;
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var constants = require('../protocol/constants');
 var utils = require('../utils/utils');
 var assert = require('assert');
@@ -504,7 +504,7 @@ Witness.encodeItem = function encodeItem(data) {
     throw new Error('Non-push opcode in witness.');
   }
 
-  if (bn.isBN(data))
+  if (BN.isBN(data))
     return Script.array(data);
 
   if (typeof data === 'string')
diff --git a/lib/utils/utils.js b/lib/utils/utils.js
index b27ba3ac..dd335fb8 100644
--- a/lib/utils/utils.js
+++ b/lib/utils/utils.js
@@ -17,7 +17,7 @@ var utils = exports;
 
 var assert = require('assert');
 var base58 = require('./base58');
-var bn = require('bn.js');
+var BN = require('bn.js');
 var util = require('util');
 var Number, Math, Date;
 var fs, lazy;
@@ -641,15 +641,15 @@ utils.fromCompact = function fromCompact(compact) {
   var num;
 
   if (compact === 0)
-    return new bn(0);
+    return new BN(0);
 
   // Logic ported from btcd since
   // the bitcoind code is a nightmare.
   if (exponent <= 3) {
     mantissa >>>= 8 * (3 - exponent);
-    num = new bn(mantissa);
+    num = new BN(mantissa);
   } else {
-    num = new bn(mantissa);
+    num = new BN(mantissa);
     num.iushln(8 * (exponent - 3));
   }
 
@@ -715,7 +715,7 @@ utils.testTarget = function testTarget(hash, target) {
   if (target.isNeg() || target.cmpn(0) === 0)
     return false;
 
-  hash = new bn(hash, 'le');
+  hash = new BN(hash, 'le');
 
   if (hash.cmp(target) > 0)
     return false;
@@ -774,14 +774,14 @@ utils.time = function time(date) {
  * @const {BN}
  */
 
-utils.U32 = new bn(0xffffffff);
+utils.U32 = new BN(0xffffffff);
 
 /**
  * UINT64_MAX
  * @const {BN}
  */
 
-utils.U64 = new bn('ffffffffffffffff', 'hex');
+utils.U64 = new BN('ffffffffffffffff', 'hex');
 
 /**
  * Create a 64 bit nonce.
@@ -797,7 +797,7 @@ utils.nonce = function _nonce(buffer) {
   if (buffer)
     return nonce;
 
-  return new bn(nonce);
+  return new BN(nonce);
 };
 
 /**
@@ -811,7 +811,7 @@ utils.readU64 = function readU64(data, off) {
   var num;
   off = off >>> 0;
   num = data.slice(off, off + 8);
-  return new bn(num, 'le');
+  return new BN(num, 'le');
 };
 
 /**
@@ -825,7 +825,7 @@ utils.readU64BE = function readU64BE(data, off) {
   var num;
   off = off >>> 0;
   num = data.slice(off, off + 8);
-  return new bn(num, 'be');
+  return new BN(num, 'be');
 };
 
 /**
@@ -843,9 +843,9 @@ utils.read64 = function read64(data, off) {
   num = data.slice(off, off + 8);
 
   if (num[num.length - 1] & 0x80)
-    return new bn(num, 'le').notn(64).addn(1).neg();
+    return new BN(num, 'le').notn(64).addn(1).neg();
 
-  return new bn(num, 'le');
+  return new BN(num, 'le');
 };
 
 /**
@@ -863,9 +863,9 @@ utils.read64BE = function read64BE(data, off) {
   num = data.slice(off, off + 8);
 
   if (num[0] & 0x80)
-    return new bn(num, 'be').notn(64).addn(1).neg();
+    return new BN(num, 'be').notn(64).addn(1).neg();
 
-  return new bn(num, 'be');
+  return new BN(num, 'be');
 };
 
 /**
@@ -1177,7 +1177,7 @@ utils.readVarint = function readVarint(data, off, big) {
       value = data.readUInt32LE(off + 1, true);
       assert(value > 0xffff);
       if (big)
-        value = new bn(value);
+        value = new BN(value);
       break;
     case 0xfd:
       size = 3;
@@ -1185,13 +1185,13 @@ utils.readVarint = function readVarint(data, off, big) {
       value = data[off + 1] | (data[off + 2] << 8);
       assert(value >= 0xfd);
       if (big)
-        value = new bn(value);
+        value = new BN(value);
       break;
     default:
       size = 1;
       value = data[off];
       if (big)
-        value = new bn(value);
+        value = new BN(value);
       break;
   }
 
@@ -1209,7 +1209,7 @@ utils.readVarint = function readVarint(data, off, big) {
 utils.writeVarint = function writeVarint(dst, num, off) {
   off = off >>> 0;
 
-  if (bn.isBN(num)) {
+  if (BN.isBN(num)) {
     if (num.bitLength() > 32) {
       dst[off] = 0xff;
       utils.writeU64(dst, num, off + 1);
@@ -1254,7 +1254,7 @@ utils.writeVarint = function writeVarint(dst, num, off) {
  */
 
 utils.sizeVarint = function sizeVarint(num) {
-  if (bn.isBN(num)) {
+  if (BN.isBN(num)) {
     if (num.bitLength() > 32)
       return 9;
     num = num.toNumber();
@@ -1295,7 +1295,7 @@ utils.readVarint2 = function readVarint2(data, off, big) {
 
     if (num >= 0x3fffffffffff) {
       assert(big, 'Number exceeds 2^53-1.');
-      bnum = new bn(num);
+      bnum = new BN(num);
       num = 0;
     }
 
@@ -1318,7 +1318,7 @@ utils.readVarint2 = function readVarint2(data, off, big) {
     return { size: size, value: bnum };
 
   if (big)
-    num = new bn(num);
+    num = new BN(num);
 
   return { size: size, value: num };
 };
@@ -1335,7 +1335,7 @@ utils.writeVarint2 = function writeVarint2(dst, num, off) {
   var tmp = [];
   var len = 0;
 
-  if (bn.isBN(num)) {
+  if (BN.isBN(num)) {
     if (num.bitLength() > 53) {
       for (;;) {
         tmp[len] = (num.words[0] & 0x7f) | (len ? 0x80 : 0x00);
@@ -1386,7 +1386,7 @@ utils.writeVarint2 = function writeVarint2(dst, num, off) {
 utils.sizeVarint2 = function sizeVarint2(num) {
   var size = 0;
 
-  if (bn.isBN(num)) {
+  if (BN.isBN(num)) {
     if (num.bitLength() > 53) {
       num = num.clone();
 
diff --git a/lib/workers/framer.js b/lib/workers/framer.js
index 1e5f18d3..e58b8eb8 100644
--- a/lib/workers/framer.js
+++ b/lib/workers/framer.js
@@ -8,7 +8,7 @@
 'use strict';
 
 var EventEmitter = require('events').EventEmitter;
-var bn = require('bn.js');
+var BN = require('bn.js');
 var utils = require('../utils/utils');
 var assert = require('assert');
 var BufferWriter = require('../utils/writer');
@@ -97,7 +97,7 @@ Framer.item = function _item(item, writer) {
       } else if (item instanceof KeyRing) {
         p.writeU8(44);
         item.toRaw(p);
-      } else if (bn.isBN(item)) {
+      } else if (BN.isBN(item)) {
         p.writeU8(10);
         p.writeVarBytes(item.toArrayLike(Buffer));
       } else if (Buffer.isBuffer(item)) {
diff --git a/lib/workers/parser.js b/lib/workers/parser.js
index 9f449e1d..d67f17fd 100644
--- a/lib/workers/parser.js
+++ b/lib/workers/parser.js
@@ -8,7 +8,7 @@
 'use strict';
 
 var EventEmitter = require('events').EventEmitter;
-var bn = require('bn.js');
+var BN = require('bn.js');
 var utils = require('../utils/utils');
 var assert = require('assert');
 var BufferReader = require('../utils/reader');
@@ -180,7 +180,7 @@ Parser.parseItem = function parseItem(data) {
         items[p.readVarString('utf8')] = Parser.parseItem(p);
       return items;
     case 10:
-      return new bn(p.readVarBytes());
+      return new BN(p.readVarBytes());
     case 40:
       return Script.fromRaw(p.readVarBytes());
     case 41:
diff --git a/scripts/gen.js b/scripts/gen.js
index 8f8a31dc..2ec4d033 100644
--- a/scripts/gen.js
+++ b/scripts/gen.js
@@ -4,7 +4,7 @@ var bcoin = require('bcoin');
 var constants = bcoin.constants;
 var opcodes = constants.opcodes;
 var utils = bcoin.utils;
-var bn = require('bn.js');
+var BN = require('bn.js');
 
 function createGenesisBlock(options) {
   var flags = options.flags;
@@ -39,7 +39,7 @@ function createGenesisBlock(options) {
         index: 0xffffffff
       },
       script: [
-        bcoin.opcode.fromNumber(new bn(486604799)),
+        bcoin.opcode.fromNumber(new BN(486604799)),
         bcoin.opcode.fromPush(new Buffer([4])),
         bcoin.opcode.fromData(flags)
       ],
diff --git a/test/aes-test.js b/test/aes-test.js
index d4617102..71f452aa 100644
--- a/test/aes-test.js
+++ b/test/aes-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var utils = require('../lib/utils/utils');
 var crypto = require('../lib/crypto/crypto');
 var assert = require('assert');
diff --git a/test/bip150-test.js b/test/bip150-test.js
index 151806cf..017714bb 100644
--- a/test/bip150-test.js
+++ b/test/bip150-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
 var crypto = require('../lib/crypto/crypto');
diff --git a/test/bip151-test.js b/test/bip151-test.js
index 39ac2746..1135ec98 100644
--- a/test/bip151-test.js
+++ b/test/bip151-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
 var crypto = require('../lib/crypto/crypto');
diff --git a/test/bip70-test.js b/test/bip70-test.js
index 0af9ec60..23af3079 100644
--- a/test/bip70-test.js
+++ b/test/bip70-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
 var crypto = require('../lib/crypto/crypto');
diff --git a/test/block-test.js b/test/block-test.js
index 0769311e..5e4f2111 100644
--- a/test/block-test.js
+++ b/test/block-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
 var crypto = require('../lib/crypto/crypto');
diff --git a/test/chain-test.js b/test/chain-test.js
index 61826ac5..938745d5 100644
--- a/test/chain-test.js
+++ b/test/chain-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('regtest');
 var constants = bcoin.constants;
 var utils = bcoin.utils;
diff --git a/test/hd-test.js b/test/hd-test.js
index 8b3f6bcb..afbb10dc 100644
--- a/test/hd-test.js
+++ b/test/hd-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
 var crypto = require('../lib/crypto/crypto');
diff --git a/test/http-test.js b/test/http-test.js
index 05d8a311..b115f878 100644
--- a/test/http-test.js
+++ b/test/http-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('regtest');
 var constants = bcoin.constants;
 var network = bcoin.networks;
diff --git a/test/mempool-test.js b/test/mempool-test.js
index 73fdb002..8452c9cb 100644
--- a/test/mempool-test.js
+++ b/test/mempool-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var constants = bcoin.constants;
 var utils = bcoin.utils;
diff --git a/test/mnemonic-test.js b/test/mnemonic-test.js
index 8d2720cb..b2feb382 100644
--- a/test/mnemonic-test.js
+++ b/test/mnemonic-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
 var crypto = require('../lib/crypto/crypto');
diff --git a/test/script-test.js b/test/script-test.js
index 06b1ae22..3b49dd20 100644
--- a/test/script-test.js
+++ b/test/script-test.js
@@ -9,7 +9,7 @@ var crypto = require('../lib/crypto/crypto');
 var constants = bcoin.constants;
 var opcodes = bcoin.constants.opcodes;
 var scripts = require('./data/script_tests');
-var bn = require('bn.js');
+var BN = require('bn.js');
 
 describe('Script', function() {
   it('should encode/decode script', function() {
diff --git a/test/tx-test.js b/test/tx-test.js
index a0f0071c..eb0c4648 100644
--- a/test/tx-test.js
+++ b/test/tx-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var assert = require('assert');
 var utils = bcoin.utils;
@@ -499,14 +499,14 @@ describe('TX', function() {
       }],
       locktime: 0
     });
-    tx.outputs[0].value = new bn('00ffffffffffffff', 'hex');
+    tx.outputs[0].value = new BN('00ffffffffffffff', 'hex');
     assert(tx.outputs[0].value.bitLength() === 56);
     var raw = tx.toRaw()
     assert.throws(function() {
       bcoin.tx.fromRaw(raw);
     });
     delete tx._raw;
-    tx.outputs[0].value = new bn('00ffffffffffffff', 'hex').ineg();
+    tx.outputs[0].value = new BN('00ffffffffffffff', 'hex').ineg();
     assert(tx.outputs[0].value.bitLength() === 56);
     var raw = tx.toRaw()
     assert.throws(function() {
diff --git a/test/utils-test.js b/test/utils-test.js
index 6742d604..7061d9f1 100644
--- a/test/utils-test.js
+++ b/test/utils-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var assert = require('assert');
 var utils = bcoin.utils;
@@ -161,27 +161,27 @@ describe('Utils', function() {
   });
 
   var unsigned = [
-    new bn('ffeeffee'),
-    new bn('001fffeeffeeffee'),
-    new bn('eeffeeff'),
-    new bn('001feeffeeffeeff'),
-    new bn(0),
-    new bn(1)
+    new BN('ffeeffee'),
+    new BN('001fffeeffeeffee'),
+    new BN('eeffeeff'),
+    new BN('001feeffeeffeeff'),
+    new BN(0),
+    new BN(1)
   ];
 
   var signed = [
-    new bn('ffeeffee'),
-    new bn('001fffeeffeeffee'),
-    new bn('eeffeeff'),
-    new bn('001feeffeeffeeff'),
-    new bn(0),
-    new bn(1),
-    new bn('ffeeffee').ineg(),
-    new bn('001fffeeffeeffee').ineg(),
-    new bn('eeffeeff').ineg(),
-    new bn('001feeffeeffeeff').ineg(),
-    new bn(0).ineg(),
-    new bn(1).ineg()
+    new BN('ffeeffee'),
+    new BN('001fffeeffeeffee'),
+    new BN('eeffeeff'),
+    new BN('001feeffeeffeeff'),
+    new BN(0),
+    new BN(1),
+    new BN('ffeeffee').ineg(),
+    new BN('001fffeeffeeffee').ineg(),
+    new BN('eeffeeff').ineg(),
+    new BN('001feeffeeffeeff').ineg(),
+    new BN(0).ineg(),
+    new BN(1).ineg()
   ];
 
   unsigned.forEach(function(num) {
diff --git a/test/wallet-test.js b/test/wallet-test.js
index 3178ccbe..a410c1db 100644
--- a/test/wallet-test.js
+++ b/test/wallet-test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var bn = require('bn.js');
+var BN = require('bn.js');
 var bcoin = require('../').set('main');
 var constants = bcoin.constants;
 var network = bcoin.networks;