Added lot of junk laying around on harvie.cz

[mirrors/Programs.git] / php / frekvencni_analyza / analyze_language.php

diff --git a/php/frekvencni_analyza/analyze_language.php b/php/frekvencni_analyza/analyze_language.php
new file mode 100755 (executable)
index 0000000..12b4079
--- /dev/null
+++ b/php/frekvencni_analyza/analyze_language.php
@@ -0,0 +1,75 @@
+#!/usr/bin/php
+<?php
+//Frequency analysis 0.2
+//Harvie 2oo7
+/*
+ * Use this to crack monoalphabetic ciphers (vigenere,...)
+ * It needs good language file (ex: one for technical another for medical language, etc...)
+ * For more see this: http://en.wikipedia.org/wiki/Frequency_analysis_(cryptanalysis)
+ *
+ * Known bugs: this can assign one letter to more crypted letters
+ */
+
+
+function freq_analyze($infile, $cereg = '[a-z ]') { //Make frequency fingerprint
+       $debug = 100;
+       $total = 0;
+       $in = fopen($infile, 'r');
+       while(!feof($in)) {
+               $c = strtolower(fgetc($in));
+               if(eregi($cereg, $c)) {
+                       if(!isset($data[$c])) $data[$c] = 0;
+                       $data[$c]++;
+                       $total++;
+               }
+       }
+       fclose($in);
+
+       //Compute percents
+       foreach($data as $c => $n) {
+               $data[$c] = ($n/$total)*100;
+               $debug -= $data[$c];
+       }
+
+       //echo("Debug: $debug\n"); //Debug
+       return($data);
+}
+
+function freq_compare($cipher, $language) { //Do analysis (from two fingerprints)
+       foreach($cipher as $c => $n) {
+               $min = 1024;
+               foreach($language as $dc => $dn) {
+                       $nmin = abs($n-$dn);
+                       //echo $nmin."\n"; //Debug
+                       if($nmin < $min) {
+                               $min = $nmin;
+                               $decrypted[$c] = $dc;
+                       }
+               }
+       }
+       
+       return($decrypted);
+}
+
+function freq_errors($decrypted) { //Test success (run with uncrypted cipher)
+       $errors = 0;
+       $total = 0;
+       foreach ($decrypted as $a => $b) {
+               if($a != $b) $errors++;
+               $total++;
+       }
+       $hits = $total - $errors;
+       $perc = round(($hits/$total)*100);
+       echo("$hits hits and $errors errors / $total total - that means, you are $perc% successfull\n");
+       return $errors;
+}
+
+///CODE//////////////////////////////////////////////////////////////////////////
+$czech = freq_analyze('czech.txt');
+//print_r($czech); //Debug
+$cipher = freq_analyze('cipher.txt');
+//print_r($cipher); //Debug
+
+$decrypted = freq_compare($cipher, $czech);
+freq_errors($decrypted);
+print_r($decrypted);
\ No newline at end of file