CryptoJs - PHP - OpenSSL

Encrypt in PHP and decrypt with CryptoJS

function CryptoJSAesEncrypt($passphrase, $plain_text){

    $salt = openssl_random_pseudo_bytes(256);
    $iv = openssl_random_pseudo_bytes(16);
    //on PHP7 can use random_bytes() istead openssl_random_pseudo_bytes()
    //or PHP5x see : https://github.com/paragonie/random_compat

    $iterations = 999;  
    $key = hash_pbkdf2("sha512", $passphrase, $salt, $iterations, 64);

    $encrypted_data = openssl_encrypt($plain_text, 'aes-256-cbc', hex2bin($key), OPENSSL_RAW_DATA, $iv);

    $data = array("ciphertext" => base64_encode($encrypted_data), "iv" => bin2hex($iv), "salt" => bin2hex($salt));
    return json_encode($data);
}

$string_json_fromPHP = CryptoJSAesEncrypt("your passphrase", "your plain text");

function CryptoJSAesDecrypt(passphrase,encrypted_json_string){

    var obj_json = JSON.parse(encrypted_json_string);

    var encrypted = obj_json.ciphertext;
    var salt = CryptoJS.enc.Hex.parse(obj_json.salt);
    var iv = CryptoJS.enc.Hex.parse(obj_json.iv);   

    var key = CryptoJS.PBKDF2(passphrase, salt, { hasher: CryptoJS.algo.SHA512, keySize: 64/8, iterations: 999});


    var decrypted = CryptoJS.AES.decrypt(encrypted, key, { iv: iv});

    return decrypted.toString(CryptoJS.enc.Utf8);
}

console.log(CryptoJSAesDecrypt('your passphrase','<?php echo $string_json_fromPHP?>'));

Encrypt in CryptoJS and decrypt with PHP

function CryptoJSAesEncrypt(passphrase, plain_text){

    var salt = CryptoJS.lib.WordArray.random(256);
    var iv = CryptoJS.lib.WordArray.random(16);

    var key = CryptoJS.PBKDF2(passphrase, salt, { hasher: CryptoJS.algo.SHA512, keySize: 64/8, iterations: 999 });

    var encrypted = CryptoJS.AES.encrypt(plain_text, key, {iv: iv});

    var data = {
        ciphertext : CryptoJS.enc.Base64.stringify(encrypted.ciphertext),
        salt : CryptoJS.enc.Hex.stringify(salt),
        iv : CryptoJS.enc.Hex.stringify(iv)    
    }

    return JSON.stringify(data);
}

function CryptoJSAesDecrypt($passphrase, $jsonString){

    $jsondata = json_decode($jsonString, true);
    try {
        $salt = hex2bin($jsondata["salt"]);
        $iv  = hex2bin($jsondata["iv"]);          
    } catch(Exception $e) { return null; }

    $ciphertext = base64_decode($jsondata["ciphertext"]);
    $iterations = 999; //same as js encrypting 

    $key = hash_pbkdf2("sha512", $passphrase, $salt, $iterations, 64);

    $decrypted= openssl_decrypt($ciphertext , 'aes-256-cbc', hex2bin($key), OPENSSL_RAW_DATA, $iv);

    return $decrypted;

}