How can I find the password entropy of a string composed pressing the closest buttons on the keyboard?
I would like to define with an algoritm in witch strings like:
querty
or
asdfghjk
are checked like bad passwords.
There is a way to calculate that without dictionaries?
I found a solution by myself.
Actually I'm checking only "qwerty" keyboards.
The getMaxPathLength function gives the maximum path of adjacent keys searching in all the directions.
<?php
/*
* Find the max path in a qwerty keyboard giving an input string
Copyright (C) 2013 Danilo Rossini <rossinidan@gmail.com>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
USAGE:
// Examples
$array = array("qwertyui"); //get 8 as result
$array = array("quedc"); //get 5 as result
$array = array("qaz"); //get 3 as result
$array = array("zxcdfvppp"); //get 6 as result
$fp = new Path_length("qwertyu");
echo $fp->getMaxPathLength();
*/
class Path_length{
private $maxPathLength = 1;
/*
* Keyboard layout: QUERTY
*/
private $matrix = array(
array("1","2","3","4","5","6","7","8","9","0"),
array("q","w","e","r","t","y","u","i","o","p"),
array("a","s","d","f","g","h","j","k","l"),
array("z","x","c","v","b","n","m"),
);
private $colSize = 10;
private $rowSize = 4;
private $arrayInput = array();
private $arraySize = null;
public function __construct($inputString) {
if(!isset($inputString)) die("NULL input array!");
$this->splitStringInArray($inputString);
$this->cycleMatrix();
}
public function getMaxPathLength(){
return $this->maxPathLength;
}
/**
* Split each element of the string into an array and store it, with his length
* in global variables
* @param type $string
*/
private function splitStringInArray($string){
$length = strlen($string);
$tmpArray = array();
for ($i=0; $i<$length; $i++) {
$tmpArray[$i] = $string[$i];
}
$this->arraySize = $length;
$this->arrayInput = $tmpArray;
}
/**
* Iterate each element of the matrix, calling the function $this->findPath
*/
private function cycleMatrix(){
for($i=0;$i<$this->colSize;$i++){
for($j=0;$j<$this->rowSize;$j++){
if(isset($this->matrix[$j][$i]) && $this->arrayInput[0]==$this->matrix[$j][$i]){
$this->findPath($j, $i, $this->maxPathLength, 1);
}
}
}
}
/**
* Recursive function that search if the closest element in the matrix (up, down, left, right)
* is contained in the input array at the cursor pointer.
* It save into $this->maxPathLength the maximum length path found.
*
* @param int $a -> x position on the matrix
* @param int $b -> y position on the matrix
* @param int $max -> max path lenght found until now by the recursive call
* @param int $c -> array cursor on the input array
* @return int
*/
private function findPath($a, $b, $max, $c){
$this->maxPathLength = max(array($this->maxPathLength, $max));
if($a>=($this->rowSize-1) && $b>=($this->colSize-1)) {
return 1;
}
if($c===$this->arraySize) {
return 1;
}
/* Search next right key */
if(isset($this->matrix[$a+1][$b]) &&
$this->matrix[$a+1][$b]===$this->arrayInput[$c] &&
$this->findPath($a+1, $b, $max+1, $c+1)){
return 1;
}
/* Search next bottom key */
if(isset($this->matrix[$a][$b+1]) &&
$this->matrix[$a][$b+1]===$this->arrayInput[$c] &&
$this->findPath($a, $b+1, $max+1, $c+1)){
return 1;
}
/* Search next left key */
if(isset($this->matrix[$a-1][$b]) &&
$this->matrix[$a-1][$b]===$this->arrayInput[$c] &&
$this->findPath($a-1, $b, $max+1, $c+1)){
return 1;
}
/* Search next up key */
if(isset($this->matrix[$a][$b-1]) &&
$this->matrix[$a][$b-1]===$this->arrayInput[$c] &&
$this->findPath($a, $b-1, $max+1, $c+1)){
return 1;
}
return 0;
}
}
Edit
New version of the previous code with detection of shifted keys.
<?php
/*
* Find the max path in a qwerty keyboard giving an input string
Copyright (C) 2013 Danilo Rossini <rossinidan@gmail.com>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
USAGE:
// Examples
$string = "qwertyui"; //get 8 as result
$string = "qwedc"; //get 5 as result
$fp = new Path_length("qwertyu");
echo $fp->getMaxPathLength();
*/
class Path_length{
private $maxPathLength = 1;
/*
* Keyboard layout: QUERTY
*/
private $keyLower = array(
array("1","2","3","4","5","6","7","8","9","0"),
array("q","w","e","r","t","y","u","i","o","p"),
array("a","s","d","f","g","h","j","k","l"),
array("z","x","c","v","b","n","m"),
);
private $keyUpper = array(
array("1","2","3","4","5","6","7","8","9","0"),
array("Q","W","E","R","T","Y","U","I","O","P"),
array("A","S","D","F","G","H","J","K","L"),
array("Z","X","C","V","B","N","M"),
);
private $matrix = array();
private $colSize = 10;
private $rowSize = 4;
private $arrayInput = array();
private $arraySize = null;
public function __construct($inputString) {
if(!isset($inputString) || !is_string($inputString)) die("Invalid input string!");
$this->initKeyboard();
$this->splitStringInArray($inputString);
$this->cycleMatrix();
}
private function initKeyboard(){
$this->matrix[0] = $this->keyLower;
$this->matrix[1] = $this->keyUpper;
}
public function getMaxPathLength(){
return $this->maxPathLength;
}
/**
* Split each element of the string into an array and store it, with his length
* in global variables
* @param type $string
*/
private function splitStringInArray($string){
$length = strlen($string);
$tmpArray = array();
for ($i=0; $i<$length; $i++) {
$tmpArray[$i] = $string[$i];
}
$this->arraySize = $length;
$this->arrayInput = $tmpArray;
}
private function isUpper($chr){
return ctype_upper($chr) ? 1 : 0;
}
/**
* Iterate each element of the matrix, calling the function $this->findPath
*/
private function cycleMatrix(){
for($i=0;$i<$this->colSize;$i++){
for($j=0;$j<$this->rowSize;$j++){
for($c=0; $c<$this->arraySize; $c++) {
$isUp = $this->isUpper($this->arrayInput[$c]);
if( isset($this->matrix[$isUp][$j][$i]) &&
$this->arrayInput[$c]===$this->matrix[$isUp][$j][$i]){
$this->findPath($j, $i, 1, $c+1, $isUp);
}
}
}
}
}
/**
* Recursive function that search if the closest element in the matrix (up, down, left, right)
* is contained in the input array at the cursor pointer.
* It save into $this->maxPathLength the maximum length path found.
*
* @param int $a -> x position on the matrix
* @param int $b -> y position on the matrix
* @param int $max -> max path lenght found until now by the recursive call
* @param int $c -> array cursor on the input array
* @return int
*/
private function findPath($a, $b, $max, $c, $isUp){
$this->maxPathLength = max(array($this->maxPathLength, $max));
if($a>=($this->rowSize-1) && $b>=($this->colSize-1)) {
return 1;
}
if($c===$this->arraySize) {
return 1;
}
/* Search next right key */
if(isset($this->matrix[$isUp][$a+1][$b]) &&
$this->matrix[$isUp][$a+1][$b]===$this->arrayInput[$c] &&
$this->findPath($a+1, $b, $max+1, $c+1, $isUp)){
return 1;
}
/* Search next bottom key */
if(isset($this->matrix[$isUp][$a][$b+1]) &&
$this->matrix[$isUp][$a][$b+1]===$this->arrayInput[$c] &&
$this->findPath($a, $b+1, $max+1, $c+1, $isUp)){
return 1;
}
/* Search next left key */
if(isset($this->matrix[$isUp][$a-1][$b]) &&
$this->matrix[$isUp][$a-1][$b]===$this->arrayInput[$c] &&
$this->findPath($a-1, $b, $max+1, $c+1, $isUp)){
return 1;
}
/* Search next up key */
if(isset($this->matrix[$isUp][$a][$b-1]) &&
$this->matrix[$isUp][$a][$b-1]===$this->arrayInput[$c] &&
$this->findPath($a, $b-1, $max+1, $c+1, $isUp)){
return 1;
}
return 0;
}
}