diff --git a/test/test.Key.js b/test/test.Key.js
index 87fce8f..09a631d 100644
--- a/test/test.Key.js
+++ b/test/test.Key.js
@@ -130,7 +130,25 @@ describe('Key', function() {
     ret.should.equal(false);
   });
 
+  describe('generateSync', function() {
+    it('should not generate the same key twice in a row', function() {
+      var key1 = Key.generateSync();
+      var key2 = Key.generateSync();
+      key1.private.toString('hex').should.not.equal(key2.private.toString('hex'));
+    });
+  });
+
   describe('signSync', function() {
+    it('should not generate the same signature twice in a row', function() {
+      var hash = coinUtil.sha256('my data');
+      var key = new Key();
+      key.private = coinUtil.sha256('a fake private key');
+      key.regenerateSync();
+      var sig1 = key.signSync(hash);
+      var sig2 = key.signSync(hash);
+      sig1.toString('hex').should.not.equal(sig2.toString('hex'));
+    });
+
     it('should sign 10 times and have a different signature each time', function() {
       var key = new Key();
       key.private = coinUtil.sha256('my fake private key');
diff --git a/test/test.Message.js b/test/test.Message.js
index 9ec581f..413cba8 100644
--- a/test/test.Message.js
+++ b/test/test.Message.js
@@ -13,6 +13,15 @@ describe('Message', function() {
       var sig = Message.sign('my message', key);
       sig.length.should.be.greaterThan(0);
     });
+
+    it('should not sign a message the same way twice', function() {
+      var key = new bitcore.Key();
+      key.private = coinUtil.sha256('a fake private key');
+      key.regenerateSync();
+      var sig1 = Message.sign('my message', key);
+      var sig2 = Message.sign('my message', key);
+      sig1.toString('hex').should.not.equal(sig2.toString('hex'));
+    });
   });
 
   describe('verifyWithPubKey', function() {