AES-256 for php, with php module mcrypt, for more see: http://php.net/manual/en/function.mcrypt-encrypt.php

AES-256

<?php 
class MCrypt {
    private $hex_iv = '00000000000000000000000000000000'; // converted JAVA byte code in to HEX and placed it here
    private $key = 'U1MjU1M0FDOUZ.Qz'; //Same as in JAVA

    function __construct() {
        $this->key = hash('sha256', $this->key, true);
    }

    function encrypt($str) {
        $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
        mcrypt_generic_init($td, $this->key, $this->hexToStr($this->hex_iv));
        $block = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
        $pad = $block - (strlen($str) % $block);
        $str .= str_repeat(chr($pad), $pad);
        $encrypted = mcrypt_generic($td, $str);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        return base64_encode($encrypted);
    }

    function decrypt($code) {
        $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
        mcrypt_generic_init($td, $this->key, $this->hexToStr($this->hex_iv));
        $str = mdecrypt_generic($td, base64_decode($code));
        $block = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        return $this->strippadding($str);
    }

    private function addpadding($string, $blocksize = 16) {
        $len = strlen($string);
        $pad = $blocksize - ($len % $blocksize);
        $string .= str_repeat(chr($pad), $pad);
        return $string;
    }

    private function strippadding($string) {
        $slast = ord(substr($string, -1));
        $slastc = chr($slast);
        $pcheck = substr($string, -$slast);
        if (preg_match("/$slastc{" . $slast . "}/", $string)) {
            $string = substr($string, 0, strlen($string) - $slast);
            return $string;
        } else {
            return false;
        }
    }

    function hexToStr($hex) {
        $string='';
        for ($i=0; $i < strlen($hex)-1; $i+=2) {
            $string .= chr(hexdec($hex[$i].$hex[$i+1]));
        }
        return $string;
    }
}

$encryption = new MCrypt();
echo $encryption->encrypt('123456') . "\n";
echo $encryption->decrypt('tpyxISJ83dqEs3uw8bN/+w==') . "\n";