encrypting/decrypting with mcrypt

daminate

Hello, need help with mcrypt,

Just got it installed, running some tests to make sure it works. I want to encrypt sensitive info, store in mysql, retrieve, and decrypt.

With testing I can get it to encrypt, but have had no luck decrypting. Also, reading some other posts/examples on this forum and others, what is a good field type and length to store the encrypted values. I have tried a few examples from the php.net site, and this forum but no luck with the decrypting...., just spits out the encrytped value. Code and output is below:

PHP

echo('This is the test to see if mycrypt works ');

$key = '1233543565784534534';

$data = 'maynard';

echo('Gonna try to encrypt it now ');

$mcrypt_module = mcrypt_module_open('blowfish', '', MCRYPT_MODE_ECB, '');

//$mcrypt_module = mcrypt_module_open('tripledes', '', 'ecb', '');

//getting initialization vector
$mcrypt_iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($mcrypt_module), MCRYPT_RAND);
echo('Initialization vector is:'.$mcrypt_iv.' ');

//getting key size for this encryption mode
$key_size = mcrypt_enc_get_key_size($mcrypt_module);
echo('Key size is:'.$key_size.' ');

$key = substr(md5($key), 0, $key_size);
echo('Actuall key after md5 is:'.$key.' ');

mcrypt_generic_init($mcrypt_module,$key,$mcrypt_iv);

$encrypted_data = mcrypt_generic($mcrypt_module, $data);

// Terminate encryption handler
mcrypt_generic_deinit($mcrypt_module);

// Initialize encryption module for decryption
mcrypt_generic_init($mcrypt_module, $key, $mcrypt_iv);

// Decrypt encrypted string
$decrypted_data = mdecrypt_generic($mcrypt_module, $encrypted_data);

// Terminate decryption handle and close module
mcrypt_generic_deinit($mcrypt_module);
mcrypt_module_close($mcrypt_module);

// Show string
echo('Here is the data un-encrypted:'.$data.' ');
echo('Here is the encrypted data:'.$encrypted_data.' ');

echo('Here is my decrypted data:'.trim($decrypted_data).' ');

HTML

This is the test to see if mycrypt works

Gonna try to encrypt it now

Initialization vector is:äYz•Î1
Key size is:56
Actuall key after md5 is:a69961fcf9e6c7005624eef5e7c5d9c6

Here is the datad un-encrypted:maynard
Here is the encrypted_data:yÈ‡”€\…

Here is my decrypted data:yÈ‡”€\…

Any suggestions? Am I missing something simple?

lazzerous

this code has worked well for me:

$key = md5('846de49c2da3bd03a7f2e1040031e30e');  // this is another md5 hash - you can use what you want.
$ROOTDIR = "/home/path/to/web/root/html/";

// function cipher()
// takes $key & $input
// $key is password lock for this cipher
// $input is the string to be converted to 256 bit AES (rijndael) encryption
// $returns encrypted data as $encrypted data
function cipher($input)
	{
	global $key;

$td = mcrypt_module_open('rijndael-256', '', 'ofb', '');
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td));

mcrypt_generic_init($td, $key, $iv);

$encrypted_data = mcrypt_generic($td, $input);
$encrypted_data = urlencode($encrypted_data);

mcrypt_generic_deinit($td);
mcrypt_module_close($td);

$iv = urlencode($iv);
$returning = array($encrypted_data, $iv);

return $returning;
}

// function decipher
// decrypts data created using cipher() function
// returns string $descypted_data
function decipher($encrypted_data, $iiv)
	{
	global $key;
	// echo "Pre Decryption: $encrypted_data<br>\n";

$iiv = urldecode($iiv);
// echo "Decoded IV: $iiv<br>\n";
$td = mcrypt_module_open('rijndael-256', '', 'ofb', '');

mcrypt_generic_init($td, $key, $iiv);

$decrypted_data = urldecode($encrypted_data);
$decrypted_data = mdecrypt_generic($td, $decrypted_data);

mcrypt_generic_deinit($td);
mcrypt_module_close($td);

return $decrypted_data;
}

daminate

Hey lazzerous,

Thanks for throwing out some info. Unfortunately I got pretty much the same out put. Also I had to add the MCRYPT_RAND parameter to the mcrypt_create_iv func:

You had:

$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td));

Added:

$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td),MCRYPT_RAND);

You got it to run w/o that?

Below is the code for printing and passing to the funcs you supplied:

PHP

$key = md5('846de49c2da3bd03a7f2e1040031e30e'); // this is another md5 hash - you can use what you want.

$data = 'maynard';
echo('Data is:'.$data.' ');

$return_array = '';
$return_array = cipher($data);

echo('Data is:'.$data.' ');
echo('Encrypted Data is:'.$return_array[0].' ');
echo('IV is:'.$return_array[1].' ');

echo('De-Encrypted Data is:'.decipher($return_array[0],$return_array[1]).' ');

Here is the out put:

HTML

Data is:maynard

Data is:maynard
Encrypted Data is:A3k%F5%8D%7D%1D
IV is:L%84%CC%C7%9A%0EYr%A9%2A%9A%99%91%87%60%02%01%1Eq%FC%2A%25%5C%17%03M%82%B5%DB%2C%BE%D1

De-Encrypted Data is:A3kõ}

I got no love from this one, any suggestions?

lazzerous

here - this is a VERY masic usage of mcrypt - see if this werks for you...

$key = "password";
$input = "This message will self destruct in 30 seconds";

$td = mcrypt_module_open('rijndael-256', '', 'ecb', '');
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_ENCRYPT);
mcrypt_generic_init($td, $key, $iv);
$encrypted_data = mcrypt_generic($td, $input);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);

echo "Data Encrypted: <br><br>\n";
echo $encrypted_data;
echo "<br><br><br>\n";

$decrypted_data = mcrypt_decrypt('rijndael-256', $key, $encrypted_data, 'ecb', $iv);

echo "Data Decrypted: <br><br>\n";
echo $decrypted_data;
echo "<br><br><br>\n";

it's always easier to start with something small and funtional and build from there - just look at the Transformers...

daminate

Below is the output, the only way to get it to run cleanly was to change:

$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_ENCRYPT);

$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);

It complained about the expected block size of iv:

Below is the output, still no decrypting....., is there some setting or something that I am missing thats jacking my stuff up?

HTML

Data Encrypted:

Data Decrypted:

daminate

....??????

andy_latham

I'm having the same problem, someone has posted a useful comment on this page:http://php.rinet.ru/manual/en/function.mdecrypt-generic.php
It appears that there is a bug in the latest dll (19-Jan-2004) .

freebie

I posted on thread on how to do this a while back

click here to access that thread