diff --git a/package.json b/package.json
index 6e6a229..454bf6d 100644
--- a/package.json
+++ b/package.json
@@ -46,8 +46,11 @@
   },
   "dependencies": {
     "bigi": "^1.4.0",
-    "bs58check": "^1.0.4",
+    "bs58check": "^1.0.5",
+    "create-hash": "^1.1.0",
+    "create-hmac": "^1.1.3",
     "ecurve": "^1.0.0",
+    "randombytes": "^2.0.1",
     "typeforce": "^1.0.0"
   },
   "devDependencies": {
diff --git a/src/crypto.js b/src/crypto.js
index dec8a79..3c1cb73 100644
--- a/src/crypto.js
+++ b/src/crypto.js
@@ -1,4 +1,4 @@
-var crypto = require('crypto')
+var createHash = require('create-hash')
 
 function hash160 (buffer) {
   return ripemd160(sha256(buffer))
@@ -9,15 +9,15 @@ function hash256 (buffer) {
 }
 
 function ripemd160 (buffer) {
-  return crypto.createHash('rmd160').update(buffer).digest()
+  return createHash('rmd160').update(buffer).digest()
 }
 
 function sha1 (buffer) {
-  return crypto.createHash('sha1').update(buffer).digest()
+  return createHash('sha1').update(buffer).digest()
 }
 
 function sha256 (buffer) {
-  return crypto.createHash('sha256').update(buffer).digest()
+  return createHash('sha256').update(buffer).digest()
 }
 
 module.exports = {
diff --git a/src/ecdsa.js b/src/ecdsa.js
index 0455d19..c88add3 100644
--- a/src/ecdsa.js
+++ b/src/ecdsa.js
@@ -1,5 +1,5 @@
 var assert = require('assert')
-var crypto = require('crypto')
+var createHmac = require('create-hmac')
 var typeForce = require('typeforce')
 
 var BigInteger = require('bigi')
@@ -29,7 +29,7 @@ function deterministicGenerateK (curve, hash, d, checkSig) {
   k.fill(0)
 
   // Step D
-  k = crypto.createHmac('sha256', k)
+  k = createHmac('sha256', k)
     .update(v)
     .update(ZERO)
     .update(x)
@@ -37,10 +37,10 @@ function deterministicGenerateK (curve, hash, d, checkSig) {
     .digest()
 
   // Step E
-  v = crypto.createHmac('sha256', k).update(v).digest()
+  v = createHmac('sha256', k).update(v).digest()
 
   // Step F
-  k = crypto.createHmac('sha256', k)
+  k = createHmac('sha256', k)
     .update(v)
     .update(ONE)
     .update(x)
@@ -48,26 +48,26 @@ function deterministicGenerateK (curve, hash, d, checkSig) {
     .digest()
 
   // Step G
-  v = crypto.createHmac('sha256', k).update(v).digest()
+  v = createHmac('sha256', k).update(v).digest()
 
   // Step H1/H2a, ignored as tlen === qlen (256 bit)
   // Step H2b
-  v = crypto.createHmac('sha256', k).update(v).digest()
+  v = createHmac('sha256', k).update(v).digest()
 
   var T = BigInteger.fromBuffer(v)
 
   // Step H3, repeat until T is within the interval [1, n - 1] and is suitable for ECDSA
   while ((T.signum() <= 0) || (T.compareTo(curve.n) >= 0) || !checkSig(T)) {
-    k = crypto.createHmac('sha256', k)
+    k = createHmac('sha256', k)
       .update(v)
       .update(ZERO)
       .digest()
 
-    v = crypto.createHmac('sha256', k).update(v).digest()
+    v = createHmac('sha256', k).update(v).digest()
 
     // Step H1/H2a, again, ignored as tlen === qlen (256 bit)
     // Step H2b again
-    v = crypto.createHmac('sha256', k).update(v).digest()
+    v = createHmac('sha256', k).update(v).digest()
     T = BigInteger.fromBuffer(v)
   }
 
diff --git a/src/eckey.js b/src/eckey.js
index af7fda2..06bed6a 100644
--- a/src/eckey.js
+++ b/src/eckey.js
@@ -1,9 +1,9 @@
 var assert = require('assert')
 var base58check = require('bs58check')
-var crypto = require('crypto')
 var ecdsa = require('./ecdsa')
-var typeForce = require('typeforce')
 var networks = require('./networks')
+var randomBytes = require('randombytes')
+var typeForce = require('typeforce')
 
 var BigInteger = require('bigi')
 var ECPubKey = require('./ecpubkey')
@@ -47,7 +47,7 @@ ECKey.fromWIF = function (string) {
 }
 
 ECKey.makeRandom = function (compressed, rng) {
-  rng = rng || crypto.randomBytes
+  rng = rng || randomBytes
 
   var buffer = rng(32)
   typeForce('Buffer', buffer)
diff --git a/src/hdnode.js b/src/hdnode.js
index f0aa613..9152e1d 100644
--- a/src/hdnode.js
+++ b/src/hdnode.js
@@ -1,7 +1,7 @@
 var assert = require('assert')
 var base58check = require('bs58check')
 var bcrypto = require('./crypto')
-var crypto = require('crypto')
+var createHmac = require('create-hmac')
 var typeForce = require('typeforce')
 var networks = require('./networks')
 
@@ -62,7 +62,7 @@ HDNode.fromSeedBuffer = function (seed, network) {
   assert(seed.length >= 16, 'Seed should be at least 128 bits')
   assert(seed.length <= 64, 'Seed should be at most 512 bits')
 
-  var I = crypto.createHmac('sha512', HDNode.MASTER_SECRET).update(seed).digest()
+  var I = createHmac('sha512', HDNode.MASTER_SECRET).update(seed).digest()
   var IL = I.slice(0, 32)
   var IR = I.slice(32)
 
@@ -225,7 +225,7 @@ HDNode.prototype.derive = function (index) {
     ])
   }
 
-  var I = crypto.createHmac('sha512', this.chainCode).update(data).digest()
+  var I = createHmac('sha512', this.chainCode).update(data).digest()
   var IL = I.slice(0, 32)
   var IR = I.slice(32)