PHP正反加密解密类

<?php

$ralphabet =

"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890

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

$alphabet = $ralphabet . $ralphabet;

class Crypto {

function encrypt ($password,$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++;

}

return $decrypted_string;

}

function cryption_table ($password) {

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));

}

print "<table border=1 cellpadding="0" cellspacing="0">n";

print "<tr><td></td>";

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

{

print "<td align="center"><font size="2" face="arial">" . substr($ralphabet,$j,1) . "</td>n";

}

print "</tr>";

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

{

print "<tr><td align="right"><font size="2"><b>" . ($i+1) . "|</b></font></td>";

for( $k=0; $k<strlen($pos_alpha_ary[$i]); $k++ )

{

print "<td align="center"><font size="2" face="arial">" . substr($pos_alpha_ary[$i],$k,1) .

"</td>n";

}

print "</tr>";

}

print "</table>n";

}

} // end class Crypto

// Example written by Macro Zeng

// 网络技术主管座右铭：三人行其必有我师焉。http://www.ctohome.com

$ct = new Crypto;

//$ct->cryption_table($password);

echo "<form action=$PHP_SELF method=post>";

if ($mod == 2) {

$strtodecrypt = $ct->encrypt ($password,$strtoencrypt);

echo 'Encrypted String（加密后的字段）: ';

echo "<input type=text name=strtodecrypt size=45 value=$strtodecrypt>

";

echo "密码锁: <input type=text name=password size=6 value=$password>";

echo "<input type=submit value="Decrypt（解密）">";

}

else {

$strtoencrypt = $ct->decrypt ($password,$strtodecrypt);

echo 'String to Encrypt（需要加密的字段）: ';

echo "<input type=text name=strtoencrypt size=45 value=$strtoencrypt>

";

echo "密码锁: <input type=text name=password size=6 value=$password>";

echo "<input type=submit value="Encrypt（加密）">";

echo "<input type=hidden name=mod value=2>";

}

echo "</form>";

highlight_file("crypto.php");

?>
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