diff --git a/composer.json b/composer.json
index a0922c1..30f805a 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
         }
     },
     "require": {
-        "php": ">=5.3.3",
+        "php": ">=5.3.23",
         "zendframework/zend-math": "self.version",
         "zendframework/zend-stdlib": "self.version",
         "zendframework/zend-servicemanager": "self.version"
diff --git a/src/BlockCipher.php b/src/BlockCipher.php
index 03cc12d..d2c7517 100644
--- a/src/BlockCipher.php
+++ b/src/BlockCipher.php
@@ -18,7 +18,12 @@
  */
 class BlockCipher
 {
-    const KEY_DERIV_HMAC = 'sha256';
+    /**
+     * Hash algorithm for Pbkdf2
+     *
+     * @var string
+     */
+    protected $pbkdf2Hash = 'sha256';
 
     /**
      * Symmetric cipher
@@ -35,7 +40,7 @@ class BlockCipher
     protected static $symmetricPlugins = null;
 
     /**
-     * Hash algorithm fot HMAC
+     * Hash algorithm for HMAC
      *
      * @var string
      */
@@ -72,7 +77,7 @@ class BlockCipher
     /**
      * Constructor
      *
-     * @param SymmetricInterface $cipher
+     * @param  SymmetricInterface $cipher
      */
     public function __construct(SymmetricInterface $cipher)
     {
@@ -160,7 +165,7 @@ public function getCipher()
     /**
      * Set the number of iterations for Pbkdf2
      *
-     * @param  int     $num
+     * @param  int $num
      * @return BlockCipher
      */
     public function setKeyIteration($num)
@@ -183,7 +188,7 @@ public function getKeyIteration()
     /**
      * Set the salt (IV)
      *
-     * @param  string                             $salt
+     * @param  string $salt
      * @return BlockCipher
      * @throws Exception\InvalidArgumentException
      */
@@ -222,7 +227,7 @@ public function getOriginalSalt()
     /**
      * Enable/disable the binary output
      *
-     * @param  bool        $value
+     * @param  bool $value
      * @return BlockCipher
      */
     public function setBinaryOutput($value)
@@ -272,7 +277,7 @@ public function getKey()
     /**
      * Set algorithm of the symmetric cipher
      *
-     * @param  string                             $algo
+     * @param  string $algo
      * @return BlockCipher
      * @throws Exception\InvalidArgumentException
      */
@@ -321,7 +326,7 @@ public function getCipherSupportedAlgorithms()
     /**
      * Set the hash algorithm for HMAC authentication
      *
-     * @param  string                             $hash
+     * @param  string $hash
      * @return BlockCipher
      * @throws Exception\InvalidArgumentException
      */
@@ -347,19 +352,58 @@ public function getHashAlgorithm()
         return $this->hash;
     }
 
+    /**
+     * Set the hash algorithm for the Pbkdf2
+     *
+     * @param  string $hash
+     * @return BlockCipher
+     * @throws Exception\InvalidArgumentException
+     */
+    public function setPbkdf2HashAlgorithm($hash)
+    {
+        if (!Hash::isSupported($hash)) {
+            throw new Exception\InvalidArgumentException(
+                "The specified hash algorithm '{$hash}' is not supported by Zend\Crypt\Hash"
+            );
+        }
+        $this->pbkdf2Hash = $hash;
+
+        return $this;
+    }
+
+    /**
+     * Get the Pbkdf2 hash algorithm
+     *
+     * @return string
+     */
+    public function getPbkdf2HashAlgorithm()
+    {
+        return $this->pbkdf2Hash;
+    }
+
     /**
      * Encrypt then authenticate using HMAC
      *
-     * @param  string                             $data
+     * @param  string $data
      * @return string
      * @throws Exception\InvalidArgumentException
      */
     public function encrypt($data)
     {
         // 0 (as integer), 0.0 (as float) & '0' (as string) will return false, though these should be allowed
-        if (!is_string($data) || $data === '') {
+        // Must be a string, integer, or float in order to encrypt
+        if ((is_string($data) && $data === '')
+            || is_array($data)
+            || is_object($data)
+        ) {
             throw new Exception\InvalidArgumentException('The data to encrypt cannot be empty');
         }
+
+        // Cast to string prior to encrypting
+        if (!is_string($data)) {
+            $data = (string) $data;
+        }
+
         if (empty($this->cipher)) {
             throw new Exception\InvalidArgumentException('No symmetric cipher specified');
         }
@@ -372,7 +416,7 @@ public function encrypt($data)
             $this->cipher->setSalt(Rand::getBytes($this->cipher->getSaltSize(), true));
         }
         // generate the encryption key and the HMAC key for the authentication
-        $hash = Pbkdf2::calc(self::KEY_DERIV_HMAC,
+        $hash = Pbkdf2::calc($this->getPbkdf2HashAlgorithm(),
                              $this->getKey(),
                              $this->getSalt(),
                              $this->keyIteration,
@@ -397,7 +441,7 @@ public function encrypt($data)
     /**
      * Decrypt
      *
-     * @param  string                             $data
+     * @param  string $data
      * @return string|bool
      * @throws Exception\InvalidArgumentException
      */
@@ -424,7 +468,7 @@ public function decrypt($data)
         $iv      = substr($ciphertext, 0, $this->cipher->getSaltSize());
         $keySize = $this->cipher->getKeySize();
         // generate the encryption key and the HMAC key for the authentication
-        $hash = Pbkdf2::calc(self::KEY_DERIV_HMAC,
+        $hash = Pbkdf2::calc($this->getPbkdf2HashAlgorithm(),
                              $this->getKey(),
                              $iv,
                              $this->keyIteration,
diff --git a/src/Key/Derivation/Scrypt.php b/src/Key/Derivation/Scrypt.php
index 6140cb8..e4e37d7 100644
--- a/src/Key/Derivation/Scrypt.php
+++ b/src/Key/Derivation/Scrypt.php
@@ -328,7 +328,7 @@ protected static function integerify($b)
      */
     protected static function hex2bin($hex)
     {
-        if (version_compare(PHP_VERSION, '5.4') >= 0) {
+        if (PHP_VERSION_ID >= 50400) {
             return hex2bin($hex);
         }
         $len    = strlen($hex);
diff --git a/src/Password/Apache.php b/src/Password/Apache.php
index 3d90761..47be2b1 100644
--- a/src/Password/Apache.php
+++ b/src/Password/Apache.php
@@ -116,7 +116,7 @@ public function create($password)
     }
 
     /**
-     * Verify if a password is correct against an hash value
+     * Verify if a password is correct against a hash value
      *
      * @param  string  $password
      * @param  string  $hash
diff --git a/src/Password/Bcrypt.php b/src/Password/Bcrypt.php
index 851f109..b489ddd 100644
--- a/src/Password/Bcrypt.php
+++ b/src/Password/Bcrypt.php
@@ -22,8 +22,12 @@ class Bcrypt implements PasswordInterface
 
     /**
      * @var string
+     *
+     * Changed from 14 to 10 to prevent possibile DOS attacks
+     * due to the high computational time
+     * @see http://timoh6.github.io/2013/11/26/Aggressive-password-stretching.html
      */
-    protected $cost = '14';
+    protected $cost = '10';
 
     /**
      * @var string
@@ -83,7 +87,7 @@ public function create($password)
          * Check for security flaw in the bcrypt implementation used by crypt()
          * @see http://php.net/security/crypt_blowfish.php
          */
-        if ((version_compare(PHP_VERSION, '5.3.7') >= 0) && !$this->backwardCompatibility) {
+        if ((PHP_VERSION_ID >= 50307) && !$this->backwardCompatibility) {
             $prefix = '$2y$';
         } else {
             $prefix = '$2a$';
@@ -104,7 +108,7 @@ public function create($password)
     }
 
     /**
-     * Verify if a password is correct against an hash value
+     * Verify if a password is correct against a hash value
      *
      * @param  string $password
      * @param  string $hash
@@ -117,22 +121,6 @@ public function verify($password, $hash)
         if ($result === $hash) {
             return true;
         }
-        if (strlen($result) <= 13) {
-            /* This should only happen if the algorithm that generated hash is
-             * either unsupported by this version of crypt(), or is invalid.
-             *
-             * An example of when this can happen, is if you generate
-             * non-backwards-compatible hashes on 5.3.7+, and then try to verify
-             * them on < 5.3.7.
-             *
-             * This is needed, because version comparisons are not possible due
-             * to back-ported functionality by some distributions.
-             */
-            throw new Exception\RuntimeException(
-                'The supplied password hash could not be verified. Please check ' .
-                'backwards compatibility settings.'
-            );
-        }
         return false;
     }
 
diff --git a/src/Symmetric/Mcrypt.php b/src/Symmetric/Mcrypt.php
index 7410a8d..2c6c90d 100755
--- a/src/Symmetric/Mcrypt.php
+++ b/src/Symmetric/Mcrypt.php
@@ -326,7 +326,8 @@ public function getPadding()
      */
     public function encrypt($data)
     {
-        if (empty($data)) {
+        // Cannot encrypt empty string
+        if (!is_string($data) || $data === '') {
             throw new Exception\InvalidArgumentException('The data to encrypt cannot be empty');
         }
         if (null === $this->getKey()) {
diff --git a/test/BlockCipherTest.php b/test/BlockCipherTest.php
index 1940ab3..14826ff 100644
--- a/test/BlockCipherTest.php
+++ b/test/BlockCipherTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
@@ -99,6 +99,13 @@ public function testSetHashAlgorithm()
         $this->assertEquals('sha1', $this->blockCipher->getHashAlgorithm());
     }
 
+    public function testSetPbkdf2HashAlgorithm()
+    {
+        $result = $this->blockCipher->setPbkdf2HashAlgorithm('sha1');
+        $this->assertEquals($result, $this->blockCipher);
+        $this->assertEquals('sha1', $this->blockCipher->getPbkdf2HashAlgorithm());
+    }
+
     public function testSetKeyIteration()
     {
         $result = $this->blockCipher->setKeyIteration(1000);
@@ -149,6 +156,32 @@ public function testEncryptDecryptUsingBinary()
         }
     }
 
+    public function zeroValuesProvider()
+    {
+        return array(
+            '"0"'   => array(0),
+            '"0.0"' => array(0.0),
+            '"0"'   => array('0'),
+        );
+    }
+
+    /**
+     * @dataProvider zeroValuesProvider
+     */
+    public function testEncryptDecryptUsingZero($value)
+    {
+        $this->blockCipher->setKey('test');
+        $this->blockCipher->setKeyIteration(1000);
+        foreach ($this->blockCipher->getCipherSupportedAlgorithms() as $algo) {
+            $this->blockCipher->setCipherAlgorithm($algo);
+
+            $encrypted = $this->blockCipher->encrypt($value);
+            $this->assertTrue(!empty($encrypted));
+            $decrypted = $this->blockCipher->decrypt($encrypted);
+            $this->assertEquals($value, $decrypted);
+        }
+    }
+
     public function testDecryptAuthFail()
     {
         $this->blockCipher->setKey('test');
diff --git a/test/HashTest.php b/test/HashTest.php
index 92617c7..b4fc831 100644
--- a/test/HashTest.php
+++ b/test/HashTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/HmacTest.php b/test/HmacTest.php
index d2113b6..0f36290 100644
--- a/test/HmacTest.php
+++ b/test/HmacTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/Key/Derivation/Pbkdf2Test.php b/test/Key/Derivation/Pbkdf2Test.php
index 00c6be8..49154fc 100644
--- a/test/Key/Derivation/Pbkdf2Test.php
+++ b/test/Key/Derivation/Pbkdf2Test.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/Key/Derivation/SaltedS2kTest.php b/test/Key/Derivation/SaltedS2kTest.php
index 27de897..4dc6abf 100644
--- a/test/Key/Derivation/SaltedS2kTest.php
+++ b/test/Key/Derivation/SaltedS2kTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/Key/Derivation/ScryptTest.php b/test/Key/Derivation/ScryptTest.php
index 6280743..a12c276 100644
--- a/test/Key/Derivation/ScryptTest.php
+++ b/test/Key/Derivation/ScryptTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
@@ -133,12 +133,12 @@ public function testVectorScryptROMix()
      */
     public function testVectorScrypt()
     {
-        $hexOutput = '77 d6 57 62 38 65 7b 20 3b 19 ca 42 c1 8a 04 97
-                      f1 6b 48 44 e3 07 4a e8 df df fa 3f ed e2 14 42
-                      fc d0 06 9d ed 09 48 f8 32 6a 75 3a 0f c8 1f 17
-                      e8 d3 e0 fb 2e 0d 36 28 cf 35 e2 0c 38 d1 89 06';
+        $hexOutput = 'd3 3c 6e c1 81 8d aa f7 28 f5 5a fa df ea a5 58
+                      b3 8e fa 81 30 5b 35 21 a7 f1 2f 4b e0 97 e8 4d
+                      18 40 92 d2 a2 e9 3b f7 1f d1 ef e0 52 71 0f 66
+                      b9 56 ce 45 da 43 aa 90 99 de 74 06 d3 a0 5e 2a';
 
-        $result = Scrypt::calc('', '', 16, 1, 1, 64);
+        $result = Scrypt::calc('password', '', 16, 1, 1, 64);
         $this->assertEquals(64, strlen($result));
         $this->assertEquals(str_replace(array(' ',PHP_EOL),'',$hexOutput), bin2hex($result));
     }
diff --git a/test/Password/ApacheTest.php b/test/Password/ApacheTest.php
index 81e59fd..cb5aeb1 100644
--- a/test/Password/ApacheTest.php
+++ b/test/Password/ApacheTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/Password/BcryptTest.php b/test/Password/BcryptTest.php
index 09572c0..d7833cc 100644
--- a/test/Password/BcryptTest.php
+++ b/test/Password/BcryptTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
@@ -32,12 +32,9 @@ public function setUp()
         $this->bcrypt   = new Bcrypt();
         $this->salt     = '1234567890123456';
         $this->password = 'test';
-        if (version_compare(PHP_VERSION, '5.3.7') >= 0) {
-            $this->prefix = '$2y$';
-        } else {
-            $this->prefix = '$2a$';
-        }
-        $this->bcryptPassword = $this->prefix . '14$MTIzNDU2Nzg5MDEyMzQ1NeWUUefVlefsTbFhsbqKFv/vPSZBrSFVm';
+        $this->prefix = '$2y$';
+
+        $this->bcryptPassword = $this->prefix . '10$MTIzNDU2Nzg5MDEyMzQ1Nej0NmcAWSLR.oP7XOR9HD/vjUuOj100y';
     }
 
     public function testConstructByOptions()
@@ -118,38 +115,13 @@ public function testVerify()
         $this->assertFalse($this->bcrypt->verify(substr($this->password, -1), $this->bcryptPassword));
     }
 
-    public function testVerifyFailureVersion()
-    {
-        $test = (substr(crypt('test', '$2y$04$012345678901234567890123456789'), 0, 3) === '$2y');
-        if (!$test) {
-            // We don't support new style hashes, test verify failure
-            $hash = '$y2$14$MTIzNDU2Nzg5MDEyMzQ1NeWUUefVlefsTbFhsbqKFv/vPSZBrSFVm';
-            $this->setExpectedException('Zend\Crypt\Password\Exception\RuntimeException',
-                'The supplied password hash could not be verified. Please check ' .
-                'backwards compatibility settings.'
-            );
-            $this->bcrypt->verify('test', $hash);
-        } else {
-            $this->markTestSkipped('Test requires PHP which does not support $2y hashes (<5.3.7)');
-        }
-    }
-
     public function testPasswordWith8bitCharacter()
     {
         $password = 'test' . chr(128);
         $this->bcrypt->setSalt($this->salt);
 
-        if (version_compare(PHP_VERSION, '5.3.7') >= 0) {
-            $this->assertEquals('$2y$14$MTIzNDU2Nzg5MDEyMzQ1NexAbOIUHkG6Ra.TK9QxHOVUhDxOe4dkW',
+        $this->assertEquals('$2y$10$MTIzNDU2Nzg5MDEyMzQ1NemFdU/4JOrNpxMym09Mbp0m4hKTgfQo.',
                                 $this->bcrypt->create($password));
-        } else {
-            $this->setExpectedException('Zend\Crypt\Password\Exception\RuntimeException',
-                'The bcrypt implementation used by PHP can contain a security flaw ' .
-                'using password with 8-bit character. ' .
-                'We suggest to upgrade to PHP 5.3.7+ or use passwords with only 7-bit characters'
-            );
-            $output = $this->bcrypt->create($password);
-        }
     }
 
     public function testSetBackwardCompatibility()
diff --git a/test/PublicKey/DiffieHellmanTest.php b/test/PublicKey/DiffieHellmanTest.php
index 1a5ecbf..f654157 100644
--- a/test/PublicKey/DiffieHellmanTest.php
+++ b/test/PublicKey/DiffieHellmanTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/PublicKey/RsaTest.php b/test/PublicKey/RsaTest.php
index 5e2766e..e60fe4a 100644
--- a/test/PublicKey/RsaTest.php
+++ b/test/PublicKey/RsaTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/Symmetric/McryptTest.php b/test/Symmetric/McryptTest.php
index 57a8ecc..369cd12 100644
--- a/test/Symmetric/McryptTest.php
+++ b/test/Symmetric/McryptTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/Symmetric/Padding/Pkcs7Test.php b/test/Symmetric/Padding/Pkcs7Test.php
index 4bb743b..0758f01 100644
--- a/test/Symmetric/Padding/Pkcs7Test.php
+++ b/test/Symmetric/Padding/Pkcs7Test.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */
 
diff --git a/test/UtilsTest.php b/test/UtilsTest.php
index 04b0eb0..534cd57 100644
--- a/test/UtilsTest.php
+++ b/test/UtilsTest.php
@@ -3,7 +3,7 @@
  * Zend Framework (http://framework.zend.com/)
  *
  * @link      http://github.com/zendframework/zf2 for the canonical source repository
- * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
+ * @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
  * @license   http://framework.zend.com/license/new-bsd New BSD License
  */