Posted by Jochem Maas on 09/26/05 10:50

Graham Anderson wrote:
> Is this good enough encryption for daily use ?
>
> FYI, I need to keep the first part of the file unencrypted so the file
> will progressively load

hi Graham, could you explain this progressive load wotsit?

> Functions were taken from the mycrypt php page :)
>
> $chunkSize = 32768;
> $key = "6q9nKLg5"
>
> if( $fd = fopen($filepath, 'rb')){
>
> while(!feof($fd)) {
> if($gotFastStartHeaders != true){
> echo fread($fd, $chunkSize/30);
> $gotFastStartHeaders = true;
> }else{
> echo encrypt(fread($fd, $chunkSize));
> }
> }
> fclose ($fd);
> exit;
> }
>
> /
> /-----------------------------------------------------------------------
> -------------------
> // Encrypt
> function encrypt($encrypt) {
> global $key;

SIDENOTE:

having a global called $key is probably a bad idea...
some one is liable to come along and add something like the following
to your code ...:

foreach ($myArr as $key => $value) {
// do stuff that has nothing to do with encryption.
}

$val = encrypt($stuff);

if (!checkEncrypedValue($val)) {
// why is the encryption broken???
var_dump( $val, $stuff);
}

so instead of a global $key - either pass in the key to the funcs
or add the funcs to a class and store the key inside the class or an
[singleton] object of that class to protect it.

....nothing else to add I'm afraid.

> //$key = "6q9nEUg5";
> srand((double) microtime() * 1000000); //for sake of MCRYPT_RAND
> $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256,
> MCRYPT_MODE_ECB), MCRYPT_RAND);
> $passcrypt = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $encrypt,
> MCRYPT_MODE_ECB, $iv);
> $encode = base64_encode($passcrypt);
> return $encode;
> }
>
> /
> /-----------------------------------------------------------------------
> -------------------
> // Decrypt
> function decrypt($decrypt) {
> global $key;
> $decoded = base64_decode($decrypt);
> $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256,
> MCRYPT_MODE_ECB), MCRYPT_RAND);
> $decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $decoded,
> MCRYPT_MODE_ECB, $iv);
> return $decrypted;
>
> many thanks
> g
>
> On Sep 24, 2005, at 2:25 PM, Jasper Bryant-Greene wrote:
>
>> Graham Anderson wrote:
>>
>>> How do you display raw binary data of a file sent from a server
>>> with curl ?
>>
>>
>> You can probably just use file_get_contents() if allow_url_fopen is
>> enabled (it is by default).
>>
>> For binary data, base64_encode and it's friend base64_decode allow
>> you to encode and decode binary data in a normal ASCII string.
>>
>> http://php.net/file_get_contents
>> http://php.net/base64_encode
>>
>>> I want to encrypt the file with something akin to str_replace and
>>> decode it on the other side with a custom data handler
>>> Just want to make sure that I am str_replace'ing the actual data
>>> and not a representation of it :)
>>
>>
>> str_replace is not for encryption. You might want to look at mcrypt,
>> as using str_replace is probably just as bad as sending the
>> unencrypted string. It's not going to be secure.
>>
>> http://php.net/mcrypt
>>
>> --
>> Jasper Bryant-Greene
>> Freelance web developer
>> http://jasper.bryant-greene.name/
>>
>> --
>> PHP General Mailing List (http://www.php.net/)
>> To unsubscribe, visit: http://www.php.net/unsub.php
>>
>

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