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CryptM - Mcrypt encryption/cypher manager for PHP

2011-06-27

CryptM Mcrypt encryption cypher manager for PHP

class CryptM {
private $input = null;
private $output = null;
private $key = null;
//initated cypher with constant - strongest encryption type
private $cypher = MCRYPT_RIJNDAEL_256;
//initiated mode with constant
private $mode = MCRYPT_MODE_CFB;
private $cypherObject = null;
private $iv = null;
public function CryptM(){
if(!$this->checkCypher($this->cypher)){
throw new Exception('cypher not supported('.$this->cypher.')');
}
if(!$this->checkMode($this->mode)){
throw new Exception('mode not supported('.$this->mode.')');
}
/*Usage notes
//CryptM encoding class for PHP
main class usage is intended as follows
$c = new CryptM();
$result = $c->quickEncrypt('secret things','password');
$result = $c->quickDecrypt($result,'password');
//most functionality is documented and explained - returning null either means it was empty to start with or the wrong password was entered
//this is implemented by a base64 check - the encoding methodology is to attach the vector to the start of the cypher - which someone on some
//form said was bad practice, however, no one said why as it can be made public without significantly weakening the encryption
//any further queries read the documentation on MCRYPT
Object can either be created and used OO style
$c = new CryptM();
$c->setInput('blah');
$c->setKey('key');
$c->setMode('cfb');
$c->setCypher('des');
$c->encrypt();
$c->getOutput(); //same with decrypt
*/
}
private function checkCypher($cypher){
foreach(mcrypt_list_algorithms() as $m){
if($cypher == $m){
return(true);
}
}
return($false);
}
private function checkMode($mode){
foreach(mcrypt_list_modes() as $m){
if($mode == $m){
return(true);
}
}
return($false);
}
public function getInput(){
return $this->input;
}
public function setInput($input){
$this->input = $input;
}
public function getOutput(){
return $this->output;
}
public function setOutput($output){
$this->output = $output;
}
public function getKey(){
return $this->key;
}
public function setKey($key){
$this->key = $key;
}
public function getCypher(){
return $this->cypher;
}
public function setCypher($cypher){
//This is probably very naughty and quite bad practice but what the frick, we create a constant containing the correct value and copy it in the
//private class variable
if($this->checkCypher($cypher)){
define(CYPHER, $cypher);
$this->cypher = CYPHER;
return(true);
}else{
return(false);
}
}
public function getMode(){
return $this->mode;
}
public function setMode($mode){
if($this->checkMode($mode)){
define(MODE, $mode);
$this->mode = MODE;
return(true);
}else{
return(false);
}
}
public function listInfo(){
echo ' ALGORITHMS: ';
foreach(mcrypt_list_algorithms() as $m){
echo ''.$m.' ';
}
echo ' MODES: ';
foreach(mcrypt_list_modes() as $m){
echo ''.$m.' ';
}
}
private function testCypherObject($cypherObject){
echo 'CYPHER OBJECT ';
echo mcrypt_enc_get_algorithms_name($cypherObject).' ';
echo mcrypt_enc_get_block_size($cypherObject).' ';
foreach(mcrypt_enc_get_supported_key_sizes($cypherObject) as $k){
echo $k.' ';
}
}
public function encrypt(){
if(sizeof($this->key)<1){
return (false);
}
//$x = mcrypt_module_open($this->getCypher(), '', $this->getMode(), '');
//$x = $this->getCypherObject();
//create encryption vector and vector size
mcrypt_generic_init($this->getCypherObject(), $this->getKey(), $this->getInitiationVector());
$this->setOutput(mcrypt_generic($this->getCypherObject(), $this->getInput()));
$this->resetCypherObject();
}
public function decrypt(){
$this->setOutput(mcrypt_decrypt($this->getCypher(), $this->getKey(), $this->getInput(), $this->getMode(), $this->getInitiationVector()));
}
private function getCypherObject(){
//2nd and 4th paramaters are the locations of the cyphers and modes - should be defined in php.ini
if($this->cypherObject==null){
$this->cypherObject = mcrypt_module_open($this->getCypher(), '', $this->getMode(), '');
}
//$this->testCypherObject($this->cypherObject);
return($this->cypherObject);
}
private function resetCypherObject(){
mcrypt_generic_deinit($this->cypherObject);
mcrypt_module_close($this->cypherObject);
$this->cypherObject = null;
}
private function getInitiationVector(){
if($this->iv == null){
$size = mcrypt_get_iv_size($this->getCypher(), $this->getMode());
$this->iv = mcrypt_create_iv($size, MCRYPT_DEV_RANDOM);
}
return($this->iv);
}
private function resetIV(){
$this->iv = null;
}
private function quickReset(){
//as the quick en/decrypt functions are quite prescriptive in how they process data they only work
//with this cypher/mode combo so they
$this->cypher = MCRYPT_RIJNDAEL_256;
$this->mode = MCRYPT_MODE_CFB;
}
public function quickEncrypt($input,$key){
//this function assumes a lot - and tags the IV onto the start of the outputted data - ergo its not standard and wont work unless u string
//split it and process it accordingly - we also base 64 encode/decode so that we can do a half-baked test on whether we have returned valid data
//technically this makes the cypher weaker to a dictionary attack but this is PHP.. its only ever going to be half baked encryption
$this->quickReset();
$iv = $this->getInitiationVector();
mcrypt_generic_init($this->getCypherObject(), $key, $iv);
//concatinate IV with encrypted base64_cypher of the input
$e = $iv.mcrypt_generic($this->getCypherObject(), base64_encode($input));
$this->resetCypherObject();
return($e);
}
public function quickDecrypt($input,$key){
//$iv = substr($input,strlen($input)-32,32);
//$e = substr($input,0,strlen($input)-32);
$this->quickReset();
$iv = substr($input,0,32);
$e = substr($input,32,strlen($input));
//base64 is strict and will return null if the char string is not base64 encoded - null = wrong password
if($result = base64_decode(mcrypt_decrypt($this->getCypher(), $key, $e, $this->getMode(), $iv), true)){
return($result);
}return(null);
}
}