I'm encrypting/decrypting URL variables but have run into a rare problem. Occasionally, I'll be unable to successfully decrypt a variable. In other words, I encrypt "AAA" and it's decrypted as gibberish. I haven't found anything unusual about the problem variables... they seem to crop up <5% of the time. The code I'm using to encrypt/decrypt variables is:
Code: Select all
<?<?
//$input - stuff to encrypt
//$key - the secret key to use
function _mencrypt($input,$key){
$input = str_replace("\n","",$input);
$input = str_replace("\t","",$input);
$input = str_replace("\r","",$input);
$key = substr(md5($key),0,24);
$td = mcrypt_module_open ('tripledes', '', 'ecb', '');
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size ($td), MCRYPT_RAND);
mcrypt_generic_init ($td, $key, $iv);
$encrypted_data = mcrypt_generic ($td, $input);
mcrypt_generic_deinit ($td);
mcrypt_module_close ($td);
return trim(chop(base64_encode($encrypted_data)));
}
//$input - stuff to decrypt
//$key - the secret key to use
function _mdecrypt($input,$key){
$input = str_replace("\n","",$input);
$input = str_replace("\t","",$input);
$input = str_replace("\r","",$input);
$input = trim(chop(base64_decode($input)));
$td = mcrypt_module_open ('tripledes', '', 'ecb', '');
$key = substr(md5($key),0,24);
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size ($td), MCRYPT_RAND);
mcrypt_generic_init ($td, $key, $iv);
$decrypted_data = mdecrypt_generic ($td, $input);
mcrypt_generic_deinit ($td);
mcrypt_module_close ($td);
return trim(chop($decrypted_data));
}
?>
php
?>