Paul M Foster wrote:
Folks:
If I wanted to encrypt a file in PHP and then write it out to disk
(one-way encryption, requiring a password), what PHP built-ins might you
recommend to encrypt the contents of the file before writing it out to
disk?
Paul
Here's a very generic mcrypt example. IANAE
where security is concerned, but from what I've
read, BLOWFISH should be a fairly decent algorithm
for most applications. This isn't my work, can't
remember whose ... uses 3DES.
KDK
<?php
$plaintext = "Four score and seven years ago";
$cipher = MCRYPT_TRIPLEDES;
$mode = MCRYPT_MODE_ECB;
$rand_src = MCRYPT_DEV_RANDOM; //MCRYPT_DEV_RANDOM
$password = 'Extra secret password';
print ("Plaintext: $plaintext\n");
// OK, let's encrypt the data
$handle = mcrypt_module_open ($cipher, '', $mode, '');
if (!$handle)
die ("Couldn't locate open mcrypt module for '$cipher' algorithm");
$iv_size = mcrypt_enc_get_iv_size ($handle);
$ivector = mcrypt_create_iv ($iv_size, $rand_src);
if (mcrypt_generic_init ($handle, $password, $ivector) == -1)
die ("Error: mcrypt_generic_init() failed.");
$ciphertext = mcrypt_generic ($handle, $plaintext);
mcrypt_generic_end ($handle);
echo "<br> Ciphertext: " . bin2hex ($ciphertext) . "\n";
// Now let's decrypt it
$handle = mcrypt_module_open ($cipher, '', $mode, '');
if (!$handle) die ("Couldn't locate open mcrypt module for '$cipher'
algorithm");
if (mcrypt_generic_init ($handle, $password, $ivector) == -1)
die ("Error: mcrypt_generic_init() failed.");
$plaintext = mdecrypt_generic ($handle, $ciphertext);
mcrypt_generic_end ($handle);
echo "<br> Plaintext: $plaintext\n");
?>
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