diff --git a/system/libraries/Encryption.php b/system/libraries/Encryption.php
index 583ddac..e03e278 100644
--- a/system/libraries/Encryption.php
+++ b/system/libraries/Encryption.php
@@ -44,7 +44,7 @@
 	 *
 	 * @var	string
 	 */
-	protected $_cipher = 'rijndael-128';
+	protected $_cipher = 'aes-128';
 
 	/**
 	 * Cipher mode
@@ -147,11 +147,9 @@
 		}
 
 		$this->initialize($params);
-
-		isset($this->_key) OR $this->_key = config_item('encryption_key');
-		if (empty($this->_key))
+		if ( ! isset($this->_key) && strlen($key = config_item('encryption_key')) > 0)
 		{
-			return show_error('Encryption: You are required to set an encryption key in your configuration.');
+			$this->_key = $key;
 		}
 
 		log_message('debug', 'Encryption Class Initialized');
@@ -324,15 +322,8 @@
 		{
 			return FALSE;
 		}
-		elseif ( ! isset($params['key']))
-		{
-			if ( ! isset($this->_key))
-			{
-				return show_error('Encryption: You are required to set an encryption key in your configuration.');
-			}
 
-			$params['key'] = $this->hkdf($this->_key, 'sha512', NULL, strlen($this->_key), 'encryption');
-		}
+		isset($params['key']) OR $params['key'] = $this->hkdf($this->_key, 'sha512', NULL, strlen($this->_key), 'encryption');
 
 		if (($data = $this->{'_'.$this->_driver.'_encrypt'}($data, $params)) === FALSE)
 		{
@@ -479,15 +470,6 @@
 		{
 			return FALSE;
 		}
-		elseif ( ! isset($params['key']))
-		{
-			if ( ! isset($this->_key))
-			{
-				return show_error('Encryption: You are required to set an encryption key in your configuration.');
-			}
-
-			$params['key'] = $this->hkdf($this->_key, 'sha512', NULL, strlen($this->_key), 'encryption');
-		}
 
 		if (isset($params['hmac_digest']))
 		{
@@ -531,6 +513,8 @@
 			$data = substr($data, $iv_size);
 		}
 
+		isset($params['key']) OR $params['key'] = $this->hkdf($this->_key, 'sha512', NULL, strlen($this->_key), 'encryption');
+
 		return $this->{'_'.$this->_driver.'_decrypt'}($data, $params);
 	}
 
@@ -684,7 +668,7 @@
 			}
 		}
 
-		if ($params['mode'] === 'gcm' OR isset($params['hmac']) && $params['hmac'] === FALSE)
+		if ($params['mode'] === 'gcm' OR (isset($params['hmac']) && $params['hmac'] === FALSE))
 		{
 			$params['hmac_digest'] = $params['hmac_key'] = NULL;
 		}
@@ -884,9 +868,17 @@
 	 */
 	public function __get($key)
 	{
-		return in_array($key, array('cipher', 'mode', 'driver', 'drivers', 'digests'), TRUE)
-			? $this->{'_'.$key}
-			: NULL;
+		// Because aliases
+		if ($key === 'mode')
+		{
+			return array_search($this->_mode, $this->_modes[$this->_driver], TRUE);
+		}
+		elseif (in_array($key, array('cipher', 'driver', 'drivers', 'digests'), TRUE))
+		{
+			return $this->{'_'.$key};
+		}
+
+		return NULL;
 	}
 
 }
diff --git a/tests/codeigniter/libraries/Encryption_test.php b/tests/codeigniter/libraries/Encryption_test.php
index 41617c2..6bcf17b 100644
--- a/tests/codeigniter/libraries/Encryption_test.php
+++ b/tests/codeigniter/libraries/Encryption_test.php
@@ -4,13 +4,268 @@
 
 	public function set_up()
 	{
-		$this->ci_set_config('encryption_key', "\xd0\xc9\x08\xc4\xde\x52\x12\x6e\xf8\xcc\xdb\x03\xea\xa0\x3a\x5c");
-		$this->encryption = new CI_Encryption();
-		$this->ci_instance_var('encryption', $this->encryption);
+		$this->encryption = new Mock_Libraries_Encryption();
+	}
+
+	/**
+	 * __construct test
+	 *
+	 * Covers behavior with $config['encryption_key'] set or not
+	 */
+	public function test___construct()
+	{
+		// Assume no configuration from set_up()
+		$this->assertNull($this->encryption->get_key());
+
+		// Try with an empty value
+		$this->ci_set_config('encryption_key');
+		$this->encrypt = new Mock_Libraries_Encryption();
+		$this->assertNull($this->encrypt->get_key());
+
+		$this->ci_set_config('encryption_key', str_repeat("\x0", 16));
+		$this->encrypt = new Mock_Libraries_Encryption();
+		$this->assertEquals(str_repeat("\x0", 16), $this->encrypt->get_key());
 	}
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * hkdf() test
+	 *
+	 * Applies test vectors described in Appendix A(1-3) RFC5869.
+	 * Described vectors 4-7 SHA-1, which we don't support and are
+	 * therefore excluded.
+	 *
+	 * Because our implementation is a single method instead of being
+	 * split into hkdf_extract() and hkdf_expand(), we cannot test for
+	 * the PRK value. As long as the OKM is correct though, it's fine.
+	 *
+	 * @link	https://tools.ietf.org/rfc/rfc5869.txt
+	 */
+	public function test_hkdf()
+	{
+		$vectors = array(
+			// A.1: Basic test case with SHA-256
+			array(
+				'digest' => 'sha256',
+				'ikm' => "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b",
+				'salt' => "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c",
+				'length' => 42,
+				'info' => "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9",
+			//	'prk' => "\x07\x77\x09\x36\x2c\x2e\x32\xdf\x0d\xdc\x3f\x0d\xc4\x7b\xba\x63\x90\xb6\xc7\x3b\xb5\x0f\x9c\x31\x22\xec\x84\x4a\xd7\xc2\xb3\xe5",
+				'okm' => "\x3c\xb2\x5f\x25\xfa\xac\xd5\x7a\x90\x43\x4f\x64\xd0\x36\x2f\x2a\x2d\x2d\x0a\x90\xcf\x1a\x5a\x4c\x5d\xb0\x2d\x56\xec\xc4\xc5\xbf\x34\x00\x72\x08\xd5\xb8\x87\x18\x58\x65"
+			),
+			// A.2: Test with SHA-256 and longer inputs/outputs
+			array(
+				'digest' => 'sha256',
+				'ikm' => "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f",
+				'salt' => "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf",
+				'length' => 82,
+				'info' => "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff",
+			//	'prk' => "\x06\xa6\xb8\x8c\x58\x53\x36\x1a\x06\x10\x4c\x9c\xeb\x35\xb4\x5c\xef\x76\x00\x14\x90\x46\x71\x01\x4a\x19\x3f\x40\xc1\x5f\xc2\x44",
+				'okm' => "\xb1\x1e\x39\x8d\xc8\x03\x27\xa1\xc8\xe7\xf7\x8c\x59\x6a\x49\x34\x4f\x01\x2e\xda\x2d\x4e\xfa\xd8\xa0\x50\xcc\x4c\x19\xaf\xa9\x7c\x59\x04\x5a\x99\xca\xc7\x82\x72\x71\xcb\x41\xc6\x5e\x59\x0e\x09\xda\x32\x75\x60\x0c\x2f\x09\xb8\x36\x77\x93\xa9\xac\xa3\xdb\x71\xcc\x30\xc5\x81\x79\xec\x3e\x87\xc1\x4c\x01\xd5\xc1\xf3\x43\x4f\x1d\x87",
+			),
+			// A.3: Test with SHA-256 and zero-length salt/info
+			array(
+				'digest' => 'sha256',
+				'ikm' => "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b",
+				'salt' => '',
+				'length' => 42,
+				'info' => '',
+			//	'prk' => "\x19\xef\x24\xa3\x2c\x71\x7b\x16\x7f\x33\xa9\x1d\x6f\x64\x8b\xdf\x96\x59\x67\x76\xaf\xdb\x63\x77\xac\x43\x4c\x1c\x29\x3c\xcb\x04",
+				'okm' => "\x8d\xa4\xe7\x75\xa5\x63\xc1\x8f\x71\x5f\x80\x2a\x06\x3c\x5a\x31\xb8\xa1\x1f\x5c\x5e\xe1\x87\x9e\xc3\x45\x4e\x5f\x3c\x73\x8d\x2d\x9d\x20\x13\x95\xfa\xa4\xb6\x1a\x96\xc8",
+			)
+		);
+
+		foreach ($vectors as $test)
+		{
+			$this->assertEquals(
+				$test['okm'],
+				$this->encryption->hkdf(
+					$test['ikm'],
+					$test['digest'],
+					$test['salt'],
+					$test['length'],
+					$test['info']
+				)
+			);
+		}
+
+		// Test default length, it must match the digest size
+		$this->assertEquals(64, strlen($this->encryption->hkdf('foobar', 'sha512')));
+
+		// Test maximum length (RFC5869 says that it must be up to 255 times the digest size)
+		$this->assertEquals(12240, strlen($this->encryption->hkdf('foobar', 'sha384', NULL, 48 * 255)));
+		$this->assertFalse($this->encryption->hkdf('foobar', 'sha224', NULL, 28 * 255 + 1));
+
+		// CI-specific test for an invalid digest
+		$this->assertFalse($this->encryption->hkdf('fobar', 'sha1'));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * _get_params() test
+	 *
+	 * @uses	Mock_Libraries_Encryption::__get_params()
+	 */
+	public function test__get_params()
+	{
+		$key = str_repeat("\x0", 16);
+
+		// Invalid custom parameters
+		$params = array(
+			// No cipher, mode or key
+			array('cipher' => 'aes-128', 'mode' => 'cbc'),
+			array('cipher' => 'aes-128', 'key' => $key),
+			array('mode' => 'cbc', 'key' => $key),
+			// No HMAC key or not a valid digest
+			array('cipher' => 'aes-128', 'mode' => 'cbc', 'key' => $key),
+			array('cipher' => 'aes-128', 'mode' => 'cbc', 'key' => $key, 'hmac_digest' => 'sha1', 'hmac_key' => $key),
+			// Invalid mode
+			array('cipher' => 'aes-128', 'mode' => 'foo', 'key' => $key, 'hmac_digest' => 'sha256', 'hmac_key' => $key)
+		);
+
+		for ($i = 0, $c = count($params); $i < $c; $i++)
+		{
+			$this->assertFalse($this->encryption->__get_params($params[$i]));
+		}
+
+		// Valid parameters
+		$params = array(
+			'cipher' => 'aes-128',
+			'mode' => 'cbc',
+			'key' => str_repeat("\x0", 16),
+			'hmac_key' => str_repeat("\x0", 16)
+		);
+
+		$this->assertTrue(is_array($this->encryption->__get_params($params)));
+
+		$params['iv'] = NULL;
+		$params['base64'] = TRUE;
+		$params['hmac_digest'] = 'sha512';
+
+		// Including all parameters
+		$params = array(
+			'cipher' => 'aes-128',
+			'mode' => 'cbc',
+			'key' => str_repeat("\x0", 16),
+			'iv' => str_repeat("\x0", 16),
+			'base64' => FALSE,
+			'hmac_key' => str_repeat("\x0", 16),
+			'hmac_digest' => 'sha256'
+		);
+
+		$output = $this->encryption->__get_params($params);
+		unset($output['handle']);
+		$this->assertEquals($params, $output);
+
+		// HMAC disabled
+		unset($params['hmac_key'], $params['hmac_digest']);
+		$params['hmac'] = FALSE;
+		$output = $this->encryption->__get_params($params);
+		unset($output['handle'], $params['hmac']);
+		$params['hmac_digest'] = $params['hmac_key'] = NULL;
+		$this->assertEquals($params, $output);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * initialize(), encrypt(), decrypt() test
+	 *
+	 * Testing the three methods separately is not realistic as they are
+	 * designed to work together. A more thorough test for initialize()
+	 * though is the OpenSSL/MCrypt compatibility test.
+	 */
+	public function test_initialize_encrypt_decrypt()
+	{
+		$message = 'This is a plain-text message.';
+		$key = "\xd0\xc9\x08\xc4\xde\x52\x12\x6e\xf8\xcc\xdb\x03\xea\xa0\x3a\x5c";
+
+		// Default state (AES-128/Rijndael-128 in CBC mode)
+		$this->encryption->initialize(array('key' => $key));
+
+		// Was the key properly set?
+		$this->assertEquals($key, $this->encryption->get_key());
+
+		$this->assertEquals($message, $this->encryption->decrypt($this->encryption->encrypt($message)));
+
+		// Try DES in ECB mode, just for the sake of changing stuff
+		$this->encryption->initialize(array('cipher' => 'des', 'mode' => 'ecb'));
+		$this->assertEquals($message, $this->encryption->decrypt($this->encryption->encrypt($message)));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * encrypt(), decrypt test with custom parameters
+	 */
+	public function test_encrypt_decrypt_custom()
+	{
+		$message = 'Another plain-text message.';
+
+		// A random invalid parameter
+		$this->assertFalse($this->encryption->encrypt($message, array('foo')));
+		$this->assertFalse($this->encryption->decrypt($message, array('foo')));
+
+		// Custom IV (we'll check it), no HMAC, binary output
+		$params = array(
+			'cipher' => 'tripledes',
+			'mode' => 'cfb',
+			'key' => str_repeat("\x1", 16),
+			'iv' => str_repeat("\x2", 8),
+			'base64' => FALSE,
+			'hmac' => FALSE
+		);
+
+		$ciphertext = $this->encryption->encrypt($message, $params);
+		$this->assertEquals(0, strncmp($params['iv'], $ciphertext, 8));
+
+		// IV should be found in the cipher-text, no matter if it was supplied or not
+		$this->assertEquals($message, $this->encryption->decrypt($ciphertext, $params));
+		unset($params['iv']);
+		$this->assertEquals($message, $this->encryption->decrypt($ciphertext, $params));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * _mcrypt_get_handle() test
+	 */
+	public function test__mcrypt_get_handle()
+	{
+		if ($this->encryption->drivers['mcrypt'] === FALSE)
+		{
+			return $this->markTestAsSkipped('Cannot test MCrypt because it is not available.');
+		}
+
+		$this->assertTrue(is_resource($this->encryption->__driver_get_handle('mcrypt', 'rijndael-128', 'cbc')));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * _openssl_get_handle() test
+	 */
+	public function test__openssl_mcrypt_get_handle()
+	{
+		if ($this->encryption->drivers['openssl'] === FALSE)
+		{
+			return $this->markTestAsSkipped('Cannot test OpenSSL because it is not available.');
+		}
+
+		$this->assertEquals('aes-128-cbc', $this->encryption->__driver_get_handle('openssl', 'aes-128', 'cbc'));
+		$this->assertEquals('rc4-40', $this->encryption->__driver_get_handle('openssl', 'rc4-40', 'stream'));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * OpenSSL/MCrypt portability test
+	 *
+	 * Amongst the obvious stuff, _cipher_alias() is also tested here.
+	 */
 	public function test_portability()
 	{
 		if ( ! $this->encryption->drivers['mcrypt'] OR ! $this->encryption->drivers['openssl'])
@@ -116,71 +371,17 @@
 
 	// --------------------------------------------------------------------
 
-	public function test_hkdf()
+	/**
+	 * __get() test
+	 */
+	public function test_magic_get()
 	{
-		// Test vectors are described in RFC5869, Appendix A(1-3).
-		// Vectors 4-7 cover SHA-1, which we don't support.
-		//
-		// URL: https://tools.ietf.org/rfc/rfc5869.txt
-		//
-		// Our implementation doesn't split into hkdf_extract(), hkdf_expand()
-		// and therefore we can't test for the PRK value (it is included below
-		// just for consistency, hence why it's also commented out).
-		//
-		// As long as OKM is correct, then we're all fine though.
-		$vectors = array(
-			// Appendix A.1: Basic test case with SHA-256
-			array(
-				'digest' => 'sha256',
-				'ikm' => "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b",
-				'salt' => "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c",
-				'length' => 42,
-				'info' => "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9",
-//				'prk' => "\x07\x77\x09\x36\x2c\x2e\x32\xdf\x0d\xdc\x3f\x0d\xc4\x7b\xba\x63\x90\xb6\xc7\x3b\xb5\x0f\x9c\x31\x22\xec\x84\x4a\xd7\xc2\xb3\xe5",
-				'okm' => "\x3c\xb2\x5f\x25\xfa\xac\xd5\x7a\x90\x43\x4f\x64\xd0\x36\x2f\x2a\x2d\x2d\x0a\x90\xcf\x1a\x5a\x4c\x5d\xb0\x2d\x56\xec\xc4\xc5\xbf\x34\x00\x72\x08\xd5\xb8\x87\x18\x58\x65"
-			),
-			// Appendix A.2: Test with SHA-256 and longer inputs/outputs
-			array(
-				'digest' => 'sha256',
-				'ikm' => "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f",
-				'salt' => "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf",
-				'length' => 82,
-				'info' => "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff",
-//				'prk' => "\x06\xa6\xb8\x8c\x58\x53\x36\x1a\x06\x10\x4c\x9c\xeb\x35\xb4\x5c\xef\x76\x00\x14\x90\x46\x71\x01\x4a\x19\x3f\x40\xc1\x5f\xc2\x44",
-				'okm' => "\xb1\x1e\x39\x8d\xc8\x03\x27\xa1\xc8\xe7\xf7\x8c\x59\x6a\x49\x34\x4f\x01\x2e\xda\x2d\x4e\xfa\xd8\xa0\x50\xcc\x4c\x19\xaf\xa9\x7c\x59\x04\x5a\x99\xca\xc7\x82\x72\x71\xcb\x41\xc6\x5e\x59\x0e\x09\xda\x32\x75\x60\x0c\x2f\x09\xb8\x36\x77\x93\xa9\xac\xa3\xdb\x71\xcc\x30\xc5\x81\x79\xec\x3e\x87\xc1\x4c\x01\xd5\xc1\xf3\x43\x4f\x1d\x87",
-			),
-			// Appendix A.3: Test with SHA-256 and zero-length salt/info
-			array(
-				'digest' => 'sha256',
-				'ikm' => "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b",
-				'salt' => "",
-				'length' => 42,
-				'info' => "",
-//				'prk' => "\x19\xef\x24\xa3\x2c\x71\x7b\x16\x7f\x33\xa9\x1d\x6f\x64\x8b\xdf\x96\x59\x67\x76\xaf\xdb\x63\x77\xac\x43\x4c\x1c\x29\x3c\xcb\x04",
-				'okm' => "\x8d\xa4\xe7\x75\xa5\x63\xc1\x8f\x71\x5f\x80\x2a\x06\x3c\x5a\x31\xb8\xa1\x1f\x5c\x5e\xe1\x87\x9e\xc3\x45\x4e\x5f\x3c\x73\x8d\x2d\x9d\x20\x13\x95\xfa\xa4\xb6\x1a\x96\xc8",
-			)
-		);
+		$this->assertNull($this->encryption->foo);
+		$this->assertEquals(array('mcrypt', 'openssl'), array_keys($this->encryption->drivers));
 
-		foreach ($vectors as $test)
-		{
-			$this->assertEquals(
-				$test['okm'],
-				$this->encryption->hkdf(
-					$test['ikm'],
-					$test['digest'],
-					$test['salt'],
-					$test['length'],
-					$test['info']
-				)
-			);
-		}
-
-		// Test default length, it must match the digest size
-		$this->assertEquals(64, strlen($this->encryption->hkdf('foobar', 'sha512')));
-
-		// Test maximum length (RFC5869 says that it must be up to 255 times the digest size)
-		$this->assertEquals(12240, strlen($this->encryption->hkdf('foobar', 'sha384', NULL, 48 * 255)));
-		$this->assertFalse($this->encryption->hkdf('foobar', 'sha224', NULL, 28 * 255 + 1));
+		// 'stream' mode is translated into an empty string for OpenSSL
+		$this->encryption->initialize(array('cipher' => 'rc4', 'mode' => 'stream'));
+		$this->assertEquals('stream', $this->encryption->mode);
 	}
 
 }
\ No newline at end of file
diff --git a/tests/mocks/libraries/encryption.php b/tests/mocks/libraries/encryption.php
new file mode 100644
index 0000000..028eecc
--- /dev/null
+++ b/tests/mocks/libraries/encryption.php
@@ -0,0 +1,39 @@
+<?php
+
+class Mock_Libraries_Encryption extends CI_Encryption {
+
+	/**
+	 * __get_params()
+	 *
+	 * Allows public calls to the otherwise protected _get_params().
+	 */
+	public function __get_params($params)
+	{
+		return $this->_get_params($params);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * get_key()
+	 *
+	 * Allows checking for key changes.
+	 */
+	public function get_key()
+	{
+		return $this->_key;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * __driver_get_handle()
+	 *
+	 * Allows checking for _mcrypt_get_handle(), _openssl_get_handle()
+	 */
+	public function __driver_get_handle($driver, $cipher, $mode)
+	{
+		return $this->{'_'.$driver.'_get_handle'}($cipher, $mode);
+	}
+
+}
\ No newline at end of file