phaser4-rex-plugins/plugins/string/xor/Decrypt.js

Plugins of phaser4

function decrypt(str, pwd) {
    if (str == null || str.length < 8) {
        return null;
    }
    if (pwd == null || pwd.length <= 0) {
        return;
    }
    var prand = "";
    for (var i = 0; i < pwd.length; i++) {
        prand += pwd.charCodeAt(i).toString();
    }
    var spos = Math.floor(prand.length / 5);
    var mult = parseInt(prand.charAt(spos) + prand.charAt(spos * 2) + prand.charAt(spos * 3) + prand.charAt(spos * 4) + prand.charAt(spos * 5));
    var incr = Math.round(pwd.length / 2);
    var modu = Math.pow(2, 31) - 1;
    var salt = parseInt(str.substring(str.length - 8, str.length), 16);
    str = str.substring(0, str.length - 8);
    prand += salt;
    while (prand.length > 10) {
        prand = (parseInt(prand.substring(0, 10)) + parseInt(prand.substring(10, prand.length))).toString();
    }
    prand = (mult * prand + incr) % modu;
    var enc_chr = "";
    var enc_str = "";
    for (var i = 0; i < str.length; i += 2) {
        enc_chr = parseInt(parseInt(str.substring(i, i + 2), 16) ^ Math.floor((prand / modu) * 255));
        enc_str += String.fromCharCode(enc_chr);
        prand = (mult * prand + incr) % modu;
    }
    return enc_str;
}

export default function (data, pwd) {
    pwd = escape(pwd.toString());
    var result = decrypt(data, pwd);
    if (result != null) {
        result = unescape(result)
    }
    return result;
};