Last active
March 9, 2020 00:04
-
-
Save drmcarvalho/c73041ec26c8acf592608b8ad1faa35c to your computer and use it in GitHub Desktop.
Criptografia de Cesar em PHP
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
<?php | |
function mod($n, $p) { | |
if ($n < 0) { | |
$n = $p - abs($n) % $p; | |
} | |
return $n % $p; | |
} | |
function troca($valor, $chave, $opcao) { | |
$alpha = "abcdefghijklmnopqrstuvwxyz"; | |
if ($opcao == 'decrypt') { | |
$resuldado = ''; | |
for ($i = 0; $i < strlen($valor); $i++) { | |
if (preg_match('/^[a-zA-Z]+$/', $valor[$i])) { | |
$resuldado .= $alpha[mod(stripos($alpha, $valor[$i]) + $chave, 26)]; | |
} | |
else { | |
$resuldado .= $valor[$i]; | |
} | |
} | |
return $resuldado; | |
} | |
elseif ($opcao == 'encrypt') { | |
$resuldado = ''; | |
for ($i = 0; $i < strlen($valor); $i++) { | |
if (preg_match('/^[a-zA-Z]+$/', $valor[$i])) { | |
$resuldado .= $alpha[mod(stripos($alpha, $valor[$i]) - $chave, 26)]; | |
} | |
else { | |
$resuldado .= $str[$i]; | |
} | |
} | |
return $resuldado; | |
} | |
return false; | |
} | |
function encriptar($chave, $str) { | |
if ($chave <= 0) | |
return null; | |
if (!$str) | |
return null; | |
return troca($str, $chave, 'encrypt'); | |
} | |
function desencriptar($chave, $str) { | |
if ($chave <= 0) | |
return null; | |
if (!$str) | |
return null; | |
return troca($str, $chave, 'decrypt'); | |
} | |
$valor = 'mah'; | |
$valorEncriptado = encriptar(8, $valor); | |
$valorDecriptado = desencriptar(8, $valorEncriptado); | |
echo "Valor original: " . $valor . "\n"; | |
echo "Valor encriptado: " . $valorEncriptado . "\n"; | |
echo "Valor decriptado: " . $valorDecriptado . "\n"; |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment