Arquivo crypt.php


<?
$ralphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz!,.:;?~@%^*()_-=][}{/><|";

# $ralphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz\\!,.:;?~@#\$%^&*()_+-=][}{/><\"'`|";

$alphabet = $ralphabet . $ralphabet;


class Crypto {

function encrypt ($password,$strtoencrypt) {

$strtoencrypt = str_replace("\t","[tab]",$strtoencrypt);
$strtoencrypt = str_replace("\n","[new]",$strtoencrypt);
$strtoencrypt = str_replace("\r","[ret]",$strtoencrypt);

global $ralphabet;
global $alphabet;

 for( $i=0; $i<strlen($password); $i++ )
 {
   $cur_pswd_ltr = substr($password,$i,1);
   $pos_alpha_ary[] = substr(strstr($alphabet,$cur_pswd_ltr),0,strlen($ralphabet));
  }

$i=0;
$n = 0;
$nn = strlen($password);
$c = strlen($strtoencrypt);

 while($i<$c)
 {
   $encrypted_string .= substr($pos_alpha_ary[$n],strpos($ralphabet,substr($strtoencrypt,$i,1)),1);
 
   $n++;
   if($n==$nn) $n = 0;
   $i++;
  }

return $encrypted_string;

}




function decrypt ($password,$strtodecrypt) {

global $ralphabet;
global $alphabet;

 for( $i=0; $i<strlen($password); $i++ )
 {
   $cur_pswd_ltr = substr($password,$i,1);
   $pos_alpha_ary[] = substr(strstr($alphabet,$cur_pswd_ltr),0,strlen($ralphabet));
  }

$i=0;
$n = 0;
$nn = strlen($password);
$c = strlen($strtodecrypt);

 while($i<$c) {
   $decrypted_string .= substr($ralphabet,strpos($pos_alpha_ary[$n],substr($strtodecrypt,$i,1)),1);
 
   $n++;
   if($n==$nn) $n = 0;
   $i++;
  }

$decrypted_string = str_replace("[tab]","\t", $decrypted_string);
$decrypted_string = str_replace("[new]","\n", $decrypted_string);
$decrypted_string = str_replace("[ret]","\r", $decrypted_string);

return $decrypted_string;


}


function cryption_table ($password) {
 
global $ralphabet;
global $alphabet;

$table = "";
for( $i=0; $i<strlen($password); $i++ ) {
   $cur_pswd_ltr = substr($password,$i,1);
   $pos_alpha_ary[] = substr(strstr($alphabet,$cur_pswd_ltr),0,strlen($ralphabet));
  }

$table .= "<table border=1 cellpadding=\"0\" cellspacing=\"0\">\n";
$table .= "<tr><td></td>";

for( $j=0; $j<strlen($ralphabet); $j++ ) {

$ltr = substr($ralphabet,$j,1);
$table .= <<<EOF
<td align="center"><font size="2" face="arial">$ltr</td>
EOF;
}

print "</tr>";


for( $i=0; $i<count($pos_alpha_ary); $i++ ) {

$z = $i + 1;
$table .= <<<EOF
<tr><td align="right"><font size="2"><b>$z</b></font></td>
EOF;
for( $k=0; $k<strlen($pos_alpha_ary[$i]); $k++ ) {
$ltr = substr($pos_alpha_ary[$i],$k,1);
$table .= <<<EOF
<td align="center">
<font color="red" size="2" face="arial">$ltr</td>
EOF;
}
$table .= "</tr>";
}
$table .= "</table>\n";
return $table;
}
}
?>

Exemplo:
Encriptacao:
<?
include("crypt.php");
$crypt->encrypt($id . "IFEEL", "seu texto");
?>

Decriptacao:
<?
include("crypt.php");
$crypt->decrypt($id . "IFEEL", "seu texto");
?>