buffedecrypt.gml

buffedecrypt.gml

 // 39dll <3

function bufferencrypt(_key, b = global.buffer) {
	bufferdecrypt(_key, b);
}

function bufferdecrypt(_key, _buff = global.buffer) {
	
	var keylen = min(string_length(_key), 256);
	if (keylen < 0) return false;
	
	var i, j ,t, temp, xx;
	var KeyBox = array_create(256, "");
	for(i = 0; i < 256; i++) {
		KeyBox[i] = chr(i);
	}
	
	i = 0; j = 0; t = 0;
	for(i = 0; i < 256; i++) {
		j = (j + ord(KeyBox[i]) + ord(string_char_at(_key, (i % keylen) + 1))) % 256;
		temp = KeyBox[i];
		KeyBox[i] = KeyBox[j];
		KeyBox[j] = temp;
	}
	
	var _tmpBuffer = buffer_create(buffer_get_size(_buff), buffer_fixed, 1);
	buffer_copy(_buff, 0, buffer_get_size(_buff), _tmpBuffer, 0);
	
	i = 0; j = 0;
	for(xx = 0; xx < buffer_get_size(_tmpBuffer); xx++) {
		i = (i + 1) % 256;
		j = (j + ord(KeyBox[i])) % 256;
		temp = KeyBox[i];
		KeyBox[i] = KeyBox[j];
		KeyBox[j] = temp;
		t = (ord(KeyBox[i]) + ord(KeyBox[j])) % 256;
		buffer_poke(_tmpBuffer, xx, buffer_u8, buffer_peek(_tmpBuffer, xx, buffer_u8) ^ ord(KeyBox[t]));
	}
	
	buffer_resize(_buff, 0);
	buffer_copy(_tmpBuffer, 0, buffer_get_size(_tmpBuffer), _buff, 0);
	buffer_delete(_tmpBuffer);
	buffer_seek(_buff, buffer_seek_start, 0);
	
	return _buff;
}