/**
* Treat consecutive "packets" as if they are a continuous buffer.
*
* Say you have a 16-byte plaintext $plaintext. Using the default behavior, the two following code snippets
* will yield different outputs:
*
* <code>
* echo $des->encrypt(substr($plaintext, 0, 8));
* echo $des->encrypt(substr($plaintext, 8, 8));
* </code>
* <code>
* echo $des->encrypt($plaintext);
* </code>
*
* The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates
* another, as demonstrated with the following:
*
* <code>
* $des->encrypt(substr($plaintext, 0, 8));
* echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));
* </code>
* <code>
* echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));
* </code>
*
* With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different
* outputs. The reason is due to the fact that the initialization vector's change after every encryption /
* decryption round when the continuous buffer is enabled. When it's disabled, they remain constant.
*
* Put another way, when the continuous buffer is enabled, the state of the DES() object changes after each
* encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that
* continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them),
* however, they are also less intuitive and more likely to cause you problems.
*
* @see Base::enableContinuousBuffer()
* @see TripleDES::disableContinuousBuffer()
* @access public
*/
function enableContinuousBuffer()
{
parent::enableContinuousBuffer();
if ($this->mode_3cbc) {
$this->des[0]->enableContinuousBuffer();
$this->des[1]->enableContinuousBuffer();
$this->des[2]->enableContinuousBuffer();
}
}
