PHP的加密和解密程序方法

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{
srand((double)microtime()*1000000);$encrypt_key=md5(rand(0,32000));
$ctr=0; $tmp="";
for($i=0;$i<strlen($txt);$i++) {
if($ctr==strlen($encrypt_key))$ctr=0; $tmp.=substr($encrypt_key,$ctr,1).
(substr($txt,$i,1)^substr($encrypt_key,$ctr,1)); $ctr++;
}returnkeyED($tmp,$key);
}functiondecrypt($txt,$key)
{$txt=keyED($txt,$key);
$tmp=""; for($i=0;$i<strlen($txt);$i++)
{$md5=substr($txt,$i,1);
$i++; $tmp.=(substr($txt,$i,1)^$md5);
}return$tmp;
}$string="HelloWorld!!!";
//encrypt$string,andstoreitin$enc_text $enc_text=encrypt($string,$key);
//decrypttheencryptedtext$enc_text,andstoreitin$dec_text $dec_text=decrypt($enc_text,$key);
print"Originaltext:$string<Br>\n"; print"Encryptedtext:$enc_text<Br>\n";
print"Decryptedtext:$dec_text<Br>\n"; ?>