You want to prevent data being viewable as plaintext. For example, you don't want hidden form data to be revealed simply by someone viewing the source code of a web page.
Encode the data with base64_encode( ):
$personal_data = array('code' => 5123, 'blood_type' => 'O'); $info = base64_encode(serialize($personal_data)); print '<input type="hidden" name="info" value="'.$info.'">'; <input type="hidden" name="info" value="YToyOntzOjQ6ImNvZGUiO2k6NTEyMztzOjEwOiJibG9vZF90eXBlIjtzOjE6Ik8iO30=">
Decode the data with base64_decode( ) :
$personal_data = unserialize(base64_decode($_REQUEST['info'])); get_transfusion($personal_data['blood_type']);
The Base64 algorithm encodes data as a string of letters, numbers, and punctuation marks. This makes it ideal for transforming binary data into a plaintext form and also for obfuscating data.
Documentation on base64_encode( ) at http://www.php.net/base64-encode and base64_decode( ) at http://www.php.net/base64-decode; the Base64 algorithm is defined in RFC 2045, available at http://www.faqs.org/rfcs/rfc2045.html.
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