diff --git a/lib/errors/spec.js b/lib/errors/spec.js
index 3815b59..81a3e2f 100644
--- a/lib/errors/spec.js
+++ b/lib/errors/spec.js
@@ -81,6 +81,9 @@ module.exports = [{
   }, {
     name: 'DustOutputs',
     message: 'Dust amount detected in one output'
+  }, {
+    name: 'InvalidSatoshis',
+    message: 'Output satoshis are invalid',
   }, {
     name: 'FeeError',
     message: 'Fees are not correctly set {0}',
diff --git a/lib/transaction/output.js b/lib/transaction/output.js
index 66385fc..558f38e 100644
--- a/lib/transaction/output.js
+++ b/lib/transaction/output.js
@@ -9,6 +9,8 @@ var BufferWriter = require('../encoding/bufferwriter');
 var Script = require('../script');
 var $ = require('../util/preconditions');
 
+var MAX_SAFE_INTEGER = 0x1fffffffffffff;
+
 function Output(params) {
   if (!(this instanceof Output)) {
     return new Output(params);
@@ -48,16 +50,33 @@ Object.defineProperty(Output.prototype, 'satoshis', {
       this._satoshis = parseInt(num);
       this._satoshisBN = BN.fromNumber(this._satoshis);
     } else {
+      $.checkArgument(
+        JSUtil.isNaturalNumber(num),
+        'Output satoshis is not a natural number'
+      );
       this._satoshisBN = BN.fromNumber(num);
       this._satoshis = num;
     }
     $.checkState(
-      JSUtil.isPositiveInteger(this._satoshis),
-      'Output satoshis is not a positive integer'
+      JSUtil.isNaturalNumber(this._satoshis),
+      'Output satoshis is not a natural number'
     );
   }
 });
 
+Output.prototype.invalidSatoshis = function() {
+  if (this._satoshis > MAX_SAFE_INTEGER) {
+    return 'transaction txout satoshis greater than max safe integer';
+  }
+  if (this._satoshis !== this._satoshisBN.toNumber()) {
+    return 'transaction txout satoshis has corrupted value';
+  }
+  if (this._satoshis < 0) {
+    return 'transaction txout negative';
+  }
+  return false;
+};
+
 Output.prototype._fromObject = function(param) {
   this.satoshis = param.satoshis;
   if (param.script || param.scriptBuffer) {
diff --git a/lib/transaction/transaction.js b/lib/transaction/transaction.js
index 1b1b986..8749355 100644
--- a/lib/transaction/transaction.js
+++ b/lib/transaction/transaction.js
@@ -21,7 +21,6 @@ var MultiSigScriptHashInput = Input.MultiSigScriptHash;
 var Output = require('./output');
 var Script = require('../script');
 var PrivateKey = require('../privatekey');
-var Block = require('../block');
 var BN = require('../crypto/bn');
 
 /**
@@ -60,6 +59,7 @@ function Transaction(serialized) {
 
 var CURRENT_VERSION = 1;
 var DEFAULT_NLOCKTIME = 0;
+var MAX_BLOCK_SIZE = 1000000;
 
 // Minimum amount for an output for it not to be considered a dust output
 Transaction.DUST_AMOUNT = 546;
@@ -167,12 +167,22 @@ Transaction.prototype.checkedSerialize = function(opts) {
   var serializationError = this.getSerializationError(opts);
   if (serializationError) {
     serializationError.message += ' Use Transaction#uncheckedSerialize if you want to skip security checks. ' +
-      'See http://bitcore.io/guide/transaction.html#Serialization for more info.'
+      'See http://bitcore.io/guide/transaction.html#Serialization for more info.';
     throw serializationError;
   }
   return this.uncheckedSerialize();
 };
 
+Transaction.prototype.invalidSatoshis = function() {
+  var invalid = false;
+  for (var i = 0; i < this.outputs.length; i++) {
+    if (this.outputs[i].invalidSatoshis()) {
+      invalid = true;
+    }
+  }
+  return invalid;
+};
+
 /**
  * Retrieve a possible error that could appear when trying to serialize and broadcast this transaction
  *
@@ -181,11 +191,15 @@ Transaction.prototype.checkedSerialize = function(opts) {
  */
 Transaction.prototype.getSerializationError = function(opts) {
   opts = opts || {};
+
+  if (this.invalidSatoshis()) {
+    return new errors.Transaction.InvalidSatoshis();
+  }
+
   var missingChange = this._missingChange();
   var feeIsTooLarge = this._isFeeTooLarge();
   var feeIsTooSmall = this._isFeeTooSmall();
   var isFullySigned = this.isFullySigned();
-  var hasDustOutputs = this._hasDustOutputs();
 
   if (!opts.disableLargeFees && feeIsTooLarge) {
     if (missingChange) {
@@ -644,7 +658,7 @@ Transaction.prototype.getChangeOutput = function() {
  */
 Transaction.prototype.to = function(address, amount) {
   $.checkArgument(
-    JSUtil.isPositiveInteger(amount),
+    JSUtil.isNaturalNumber(amount),
     'Amount is expected to be a positive integer'
   );
   this.addOutput(new Output({
@@ -981,28 +995,28 @@ Transaction.prototype.verify = function() {
     return 'transaction txouts empty';
   }
 
-  // Size limits
-  if (this.toBuffer().length > Block.MAX_BLOCK_SIZE) {
-    return 'transaction over the maximum block size';
-  }
-
   // Check for negative or overflow output values
   var valueoutbn = new BN(0);
   for (var i = 0; i < this.outputs.length; i++) {
     var txout = this.outputs[i];
-    var valuebn = txout._satoshisBN;
-    if (valuebn.lt(BN.Zero)) {
-      return 'transaction txout ' + i + ' negative';
+
+    if (txout.invalidSatoshis()) {
+      return 'transaction txout ' + i + ' satoshis is invalid';
     }
-    if (valuebn.gt(new BN(Transaction.MAX_MONEY, 10))) {
+    if (txout._satoshisBN.gt(new BN(Transaction.MAX_MONEY, 10))) {
       return 'transaction txout ' + i + ' greater than MAX_MONEY';
     }
-    valueoutbn = valueoutbn.add(valuebn);
+    valueoutbn = valueoutbn.add(txout._satoshisBN);
     if (valueoutbn.gt(new BN(Transaction.MAX_MONEY))) {
       return 'transaction txout ' + i + ' total output greater than MAX_MONEY';
     }
   }
 
+  // Size limits
+  if (this.toBuffer().length > MAX_BLOCK_SIZE) {
+    return 'transaction over the maximum block size';
+  }
+
   // Check for duplicate inputs
   var txinmap = {};
   for (i = 0; i < this.inputs.length; i++) {
diff --git a/lib/util/js.js b/lib/util/js.js
index 02fe4f4..c53e1e1 100644
--- a/lib/util/js.js
+++ b/lib/util/js.js
@@ -70,12 +70,12 @@ module.exports = {
     return target;
   },
   /**
-   * Checks that a value is a positive integer
+   * Checks that a value is a natural number, a positive integer or zero.
    *
    * @param {*} value
    * @return {Boolean}
    */
-  isPositiveInteger: function isPositiveInteger(value) {
+  isNaturalNumber: function isNaturalNumber(value) {
     return typeof value === 'number' &&
       isFinite(value) &&
       Math.floor(value) === value &&
diff --git a/npm-shrinkwrap.json b/npm-shrinkwrap.json
index 8c35dc9..2e2a696 100644
--- a/npm-shrinkwrap.json
+++ b/npm-shrinkwrap.json
@@ -1,63 +1,43 @@
 {
   "name": "bitcore",
-  "version": "0.9.0",
+  "version": "0.12.3",
   "dependencies": {
     "bn.js": {
-      "version": "0.16.1",
-      "from": "bn.js@0.16.1",
-      "resolved": "https://registry.npmjs.org/bn.js/-/bn.js-0.16.1.tgz"
+      "version": "2.0.4",
+      "from": "bn.js@=2.0.4",
+      "resolved": "https://registry.npmjs.org/bn.js/-/bn.js-2.0.4.tgz"
     },
     "bs58": {
       "version": "2.0.0",
-      "from": "bs58@2.0.0",
+      "from": "bs58@=2.0.0",
       "resolved": "https://registry.npmjs.org/bs58/-/bs58-2.0.0.tgz"
     },
     "elliptic": {
-      "version": "0.16.0",
-      "from": "elliptic@0.16.0",
-      "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-0.16.0.tgz",
+      "version": "3.0.3",
+      "from": "elliptic@=3.0.3",
+      "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-3.0.3.tgz",
       "dependencies": {
-        "bn.js": {
-          "version": "0.16.1",
-          "from": "bn.js@0.16.1",
-          "resolved": "https://registry.npmjs.org/bn.js/-/bn.js-0.16.1.tgz"
-        },
         "brorand": {
-          "version": "1.0.1",
-          "from": "brorand@1.0.1",
-          "resolved": "https://registry.npmjs.org/brorand/-/brorand-1.0.1.tgz"
-        },
-        "hash.js": {
-          "version": "0.3.2",
-          "from": "hash.js@0.3.2",
-          "resolved": "https://registry.npmjs.org/hash.js/-/hash.js-0.3.2.tgz"
-        },
-        "inherits": {
-          "version": "2.0.1",
-          "from": "inherits@^2.0.1"
+          "version": "1.0.5",
+          "from": "brorand@^1.0.1",
+          "resolved": "https://registry.npmjs.org/brorand/-/brorand-1.0.5.tgz"
         }
       }
     },
+    "hash.js": {
+      "version": "1.0.2",
+      "from": "hash.js@^1.0.0",
+      "resolved": "https://registry.npmjs.org/hash.js/-/hash.js-1.0.2.tgz"
+    },
     "inherits": {
       "version": "2.0.1",
-      "from": "inherits@2.0.1",
+      "from": "inherits@=2.0.1",
       "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.1.tgz"
     },
-    "hash.js": {
-      "version": "0.3.2",
-      "from": "hash.js@0.3.2",
-      "resolved": "https://registry.npmjs.org/hash.js/-/hash.js-0.3.2.tgz",
-      "dependencies": {
-        "inherits": {
-          "version": "2.0.1",
-          "from": "inherits@^2.0.1"
-        }
-      }
-    },
     "lodash": {
-       "version": "2.4.1",
-       "from": "lodash@=2.4.1",
-       "resolved": "https://registry.npmjs.org/lodash/-/lodash-2.4.1.tgz"
+      "version": "2.4.1",
+      "from": "lodash@=2.4.1",
+      "resolved": "https://registry.npmjs.org/lodash/-/lodash-2.4.1.tgz"
     },
     "sha512": {
       "version": "0.0.1",
diff --git a/package.json b/package.json
index bebfdec..9f3f9c0 100644
--- a/package.json
+++ b/package.json
@@ -79,10 +79,10 @@
     "request": "browser-request"
   },
   "dependencies": {
-    "bn.js": "=0.16.1",
+    "bn.js": "=2.0.4",
     "bs58": "=2.0.0",
-    "elliptic": "=0.16.0",
-    "hash.js": "=0.3.2",
+    "elliptic": "=3.0.3",
+    "hash.js": "=1.0.2",
     "inherits": "=2.0.1",
     "lodash": "=2.4.1",
     "sha512": "=0.0.1"
diff --git a/test/transaction/deserialize.js b/test/transaction/deserialize.js
index 28993d9..e9f43b8 100644
--- a/test/transaction/deserialize.js
+++ b/test/transaction/deserialize.js
@@ -10,21 +10,25 @@ describe('Transaction deserialization', function() {
   describe('valid transaction test case', function() {
     var index = 0;
     vectors_valid.forEach(function(vector) {
-      if (vector.length > 1) {
-        var hexa = vector[1];
-        Transaction(hexa).serialize(true).should.equal(hexa);
-        index++;
-      }
+      it('vector #' + index, function() {
+        if (vector.length > 1) {
+          var hexa = vector[1];
+          Transaction(hexa).serialize(true).should.equal(hexa);
+          index++;
+        }
+      });
     });
   });
   describe('invalid transaction test case', function() {
     var index = 0;
     vectors_invalid.forEach(function(vector) {
-      if (vector.length > 1) {
-        var hexa = vector[1];
-        Transaction(hexa).serialize(true).should.equal(hexa);
-        index++;
-      }
+      it('invalid vector #' + index, function() {
+        if (vector.length > 1) {
+          var hexa = vector[1];
+          Transaction(hexa).serialize(true).should.equal(hexa);
+          index++;
+        }
+      });
     });
   });
 });
diff --git a/test/transaction/output.js b/test/transaction/output.js
index fdade46..0ded9d5 100644
--- a/test/transaction/output.js
+++ b/test/transaction/output.js
@@ -45,7 +45,7 @@ describe('Output', function() {
           satoshis: -100,
           script: Script.empty()
         });
-      }).should.throw('Output satoshis is not a positive integer');
+      }).should.throw('Output satoshis is not a natural number');
     });
 
     it('1.1', function() {
@@ -54,7 +54,7 @@ describe('Output', function() {
           satoshis: 1.1,
           script: Script.empty()
         });
-      }).should.throw('Output satoshis is not a positive integer');
+      }).should.throw('Output satoshis is not a natural number');
     });
 
     it('NaN', function() {
@@ -63,7 +63,7 @@ describe('Output', function() {
           satoshis: NaN,
           script: Script.empty()
         });
-      }).should.throw('Output satoshis is not a positive integer');
+      }).should.throw('Output satoshis is not a natural number');
     });
 
     it('Infinity', function() {
@@ -72,7 +72,7 @@ describe('Output', function() {
           satoshis: Infinity,
           script: Script.empty()
         });
-      }).should.throw('Output satoshis is not a positive integer');
+      }).should.throw('Output satoshis is not a natural number');
     });
   });
 
diff --git a/test/transaction/transaction.js b/test/transaction/transaction.js
index 2651038..7841f8a 100644
--- a/test/transaction/transaction.js
+++ b/test/transaction/transaction.js
@@ -8,6 +8,7 @@ var _ = require('lodash');
 var sinon = require('sinon');
 
 var bitcore = require('../..');
+var BN = bitcore.crypto.BN;
 var Transaction = bitcore.Transaction;
 var PrivateKey = bitcore.PrivateKey;
 var Script = bitcore.Script;
@@ -245,6 +246,18 @@ describe('Transaction', function() {
       transaction.outputs.length.should.equal(2);
       transaction.outputs[1].satoshis.should.equal(10000);
     });
+    it('if satoshis are invalid', function() {
+      var transaction = new Transaction()
+        .from(simpleUtxoWith100000Satoshis)
+        .to(toAddress, 99999)
+        .change(changeAddress)
+        .sign(privateKey);
+      transaction.outputs[0]._satoshis = 100;
+      transaction.outputs[0]._satoshisBN = new BN(101, 10);
+      expect(function() {
+        return transaction.serialize();
+      }).to.throw(errors.Transaction.InvalidSatoshis);
+    });
     it('if fee is too small, fail serialization', function() {
       var transaction = new Transaction()
         .from(simpleUtxoWith100000Satoshis)
@@ -355,7 +368,7 @@ describe('Transaction', function() {
       var buildSkipTest = function(builder, check) {
         return function() {
           var transaction = new Transaction();
-          transaction.from(simpleUtxoWith1BTC)
+          transaction.from(simpleUtxoWith1BTC);
           builder(transaction);
 
           var options = {};
@@ -410,6 +423,57 @@ describe('Transaction', function() {
     });
   });
 
+  describe('#verify', function() {
+
+    it('not if _satoshis and _satoshisBN have different values', function() {
+      var tx = new Transaction()
+        .from({
+          'txId': testPrevTx,
+          'outputIndex': 0,
+          'script': testScript,
+          'satoshis': testAmount
+        }).to('mrU9pEmAx26HcbKVrABvgL7AwA5fjNFoDc', testAmount - 10000);
+
+      tx.outputs[0]._satoshis = 100;
+      tx.outputs[0]._satoshisBN = new BN('fffffffffffffff', 16);
+      var verify = tx.verify();
+      verify.should.equal('transaction txout 0 satoshis is invalid');
+    });
+
+    it('not if _satoshis is negative', function() {
+      var tx = new Transaction()
+        .from({
+          'txId': testPrevTx,
+          'outputIndex': 0,
+          'script': testScript,
+          'satoshis': testAmount
+        }).to('mrU9pEmAx26HcbKVrABvgL7AwA5fjNFoDc', testAmount - 10000);
+
+      tx.outputs[0]._satoshis = -100;
+      tx.outputs[0]._satoshisBN = new BN(-100, 10);
+      var verify = tx.verify();
+      verify.should.equal('transaction txout 0 satoshis is invalid');
+    });
+
+    it('not if transaction is greater than max block size', function() {
+
+      var tx = new Transaction()
+        .from({
+          'txId': testPrevTx,
+          'outputIndex': 0,
+          'script': testScript,
+          'satoshis': testAmount
+        }).to('mrU9pEmAx26HcbKVrABvgL7AwA5fjNFoDc', testAmount - 10000);
+
+      tx.toBuffer = sinon.stub().returns({length: 10000000});
+
+      var verify = tx.verify();
+      verify.should.equal('transaction over the maximum block size');
+
+    });
+
+  });
+
   describe('to and from JSON', function() {
     it('takes a string that is a valid JSON and deserializes from it', function() {
       var simple = new Transaction();
@@ -616,7 +680,7 @@ describe('Transaction', function() {
       transaction.outputAmount.should.equal(99990000);
     });
     it('returns correct values for coinjoin transaction', function() {
-      // see livenet tx c16467eea05f1f30d50ed6dbc06a38539d9bb15110e4b7dc6653046a3678a718 
+      // see livenet tx c16467eea05f1f30d50ed6dbc06a38539d9bb15110e4b7dc6653046a3678a718
       var transaction = new Transaction(txCoinJoinHex);
       transaction.outputAmount.should.equal(4191290961);
       expect(function() {
diff --git a/test/util/js.js b/test/util/js.js
index 1e79d32..0928b8d 100644
--- a/test/util/js.js
+++ b/test/util/js.js
@@ -32,44 +32,49 @@ describe('js utils', function() {
 
   });
 
-  describe('isPositiveInteger', function() {
+  describe('isNaturalNumber', function() {
     it('false for float', function() {
-      var a = JSUtil.isPositiveInteger(0.1);
+      var a = JSUtil.isNaturalNumber(0.1);
       a.should.equal(false);
     });
 
     it('false for string float', function() {
-      var a = JSUtil.isPositiveInteger('0.1');
+      var a = JSUtil.isNaturalNumber('0.1');
       a.should.equal(false);
     });
 
     it('false for string integer', function() {
-      var a = JSUtil.isPositiveInteger('1');
+      var a = JSUtil.isNaturalNumber('1');
       a.should.equal(false);
     });
 
     it('false for negative integer', function() {
-      var a = JSUtil.isPositiveInteger(-1);
+      var a = JSUtil.isNaturalNumber(-1);
       a.should.equal(false);
     });
 
     it('false for negative integer string', function() {
-      var a = JSUtil.isPositiveInteger('-1');
+      var a = JSUtil.isNaturalNumber('-1');
       a.should.equal(false);
     });
 
     it('false for infinity', function() {
-      var a = JSUtil.isPositiveInteger(Infinity);
+      var a = JSUtil.isNaturalNumber(Infinity);
       a.should.equal(false);
     });
 
     it('false for NaN', function() {
-      var a = JSUtil.isPositiveInteger(NaN);
+      var a = JSUtil.isNaturalNumber(NaN);
       a.should.equal(false);
     });
 
+    it('true for zero', function() {
+      var a = JSUtil.isNaturalNumber(0);
+      a.should.equal(true);
+    });
+
     it('true for positive integer', function() {
-      var a = JSUtil.isPositiveInteger(1000);
+      var a = JSUtil.isNaturalNumber(1000);
       a.should.equal(true);
     });