MapleCustomEncryption.java

package tools;

public class MapleCustomEncryption {

    public static final byte[] encryptData(byte[] data) {
        for (int j = 0; j < 6; j++) {
            byte remember = 0;
            byte dataLength = (byte) (data.length & 0xFF);

            if (j % 2 == 0) {
                for (int i = 0; i < data.length; i++) {
                    byte cur = data[i];
                    cur = BitTools.rollLeft(cur, 3);
                    cur = (byte) (cur + dataLength);
                    cur = (byte) (cur ^ remember);
                    remember = cur;
                    cur = BitTools.rollRight(cur, dataLength & 0xFF);
                    cur = (byte) ((cur ^ 0xFFFFFFFF) & 0xFF);
                    cur = (byte) (cur + 72);
                    dataLength = (byte) (dataLength - 1);
                    data[i] = cur;
                }
            } else {
                for (int i = data.length - 1; i >= 0; i--) {
                    byte cur = data[i];
                    cur = BitTools.rollLeft(cur, 4);
                    cur = (byte) (cur + dataLength);
                    cur = (byte) (cur ^ remember);
                    remember = cur;
                    cur = (byte) (cur ^ 0x13);
                    cur = BitTools.rollRight(cur, 3);
                    dataLength = (byte) (dataLength - 1);
                    data[i] = cur;
                }
            }
        }

        return data;
    }

    public static final byte[] decryptData(byte[] data) {
        for (int j = 1; j <= 6; j++) {
            byte remember = 0;
            byte dataLength = (byte) (data.length & 0xFF);
            byte nextRemember = 0;

            if (j % 2 == 0) {
                for (int i = 0; i < data.length; i++) {
                    byte cur = data[i];
                    cur = (byte) (cur - 72);
                    cur = (byte) ((cur ^ 0xFFFFFFFF) & 0xFF);
                    cur = BitTools.rollLeft(cur, dataLength & 0xFF);
                    nextRemember = cur;
                    cur = (byte) (cur ^ remember);
                    remember = nextRemember;
                    cur = (byte) (cur - dataLength);
                    cur = BitTools.rollRight(cur, 3);
                    data[i] = cur;
                    dataLength = (byte) (dataLength - 1);
                }
            } else {
                for (int i = data.length - 1; i >= 0; i--) {
                    byte cur = data[i];
                    cur = BitTools.rollLeft(cur, 3);
                    cur = (byte) (cur ^ 0x13);
                    nextRemember = cur;
                    cur = (byte) (cur ^ remember);
                    remember = nextRemember;
                    cur = (byte) (cur - dataLength);
                    cur = BitTools.rollRight(cur, 4);
                    data[i] = cur;
                    dataLength = (byte) (dataLength - 1);
                }
            }
        }

        return data;
    }
}