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使用PHP来进行加密与解密

上一篇 / 下一篇 2006-11-27 23:50:08

<?php
$key = "This is supposed to be a secret key !!!";PHPChina 开源社区门户2r5G `&v Y
function keyED($txt,$encrypt_key)
{
5H!cF7von0$encrypt_key = md5($encrypt_key);
^Rj;[.WI!A0$ctr=0;
R'dz^8X^5e;nr\v0$tmp = "";
*k/S}7c3~:pW^0for ($i=0;$i<strlen($txt);$i++)
{
$i#y\F&nw9a@0  if ($ctr==strlen($encrypt_key)) $ctr=0;
  $tmp.= substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1);
/dtH-B Yh0  $ctr++;
1g ~^:iVQEtlo0}
return $tmp;
Hg|"guJ0}
IduOP"]\C0function encrypt($txt,$key)
{
0|QZ&]vI_C;a2n0srand((double)microtime()*1000000);
x$XMy2{s J'};x0$encrypt_key = md5(rand(0,32000));
7[)U[k$U&L \S%`0$ctr=0;
Nvf\,s+f+PDs0$tmp = "";PHPChina 开源社区门户.Y[Q/a5BW!G
for ($i=0;$i<strlen($txt);$i++)
QO(ku d0{
  if ($ctr==strlen($encrypt_key)) $ctr=0;PHPChina 开源社区门户$o9sEa$B
  $tmp.= substr($encrypt_key,$ctr,1) .
  (substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1));PHPChina 开源社区门户:o!oD Xpa
  $ctr++;
-l,Fd-R6p9\0}PHPChina 开源社区门户q(O!GW4r
return keyED($tmp,$key);
EwfJPb@*z~0}
function decrypt($txt,$key)
{
F'V(n~#t Dj X,JR}0$txt = keyED($txt,$key);
PO]p`Uj-r%`1I0$tmp = "";
for ($i=0;$i<strlen($txt);$i++)
{
  $md5 = substr($txt,$i,1);
6Ul].K\f8sgW0  $i++;
5mH\,xV7t9|.n#uV5]0  $tmp.= (substr($txt,$i,1) ^ $md5);
}
return $tmp;
z({ LlMfV0}
Qc/XfA]4UhV0$string = "Hello World !!!";
u0@EMTx0// encrypt $string, and store it in $enc_text
-@g(oEOv^;Z0$enc_text = encrypt($string,$key);
c@0e:MFKq0// decrypt the encrypted text $enc_text, and store it in $dec_text
$dec_text = decrypt($enc_text,$key);
print "Original text : $string <Br>";
print "Encrypted text : $enc_text <Br>";
print "Decrypted text : $dec_text <Br>";
X.u5Ca&o1Vr0?>