how to encrypt word document using publickey in php - php

Question

I have a problem, I want to encrypt word docs(which have only 10 Kb) using public key, and it must decrypt with private key.
I already created key pair using phpseclib library.
http://phpseclib.sourceforge.net/crypt/examples.html
and I can encrypt and decrypt string using that library. but I don't know how to encrypt file using key pair.
is there any method for this.(or using file_get_contents)
thanks for all
<?php
//create word docx using phpdocx
require("phpDocx.php");
$phpdocx = new phpdocx("word_temp\loan_app_temp.docx");
//assign
$upfno='999';
$loanid_db='1234';
$phpdocx->assign("#upfno#","$upfno");
$phpdocx->assign("#loanid#","$loanid_db");
$phpdocx->assign("#fullname#","$name");
$phpdocx->assign("#initials#","$initials");
$phpdocx->save("word_gen\loan_docs\la_".$upfno."_".$loanid_db.".docx"); // sucessfully created.
// create key pair using phpseclib
set_include_path(get_include_path() . PATH_SEPARATOR . 'phpseclib');
include('phpseclib/Crypt/RSA.php');
$rsa = new Crypt_RSA();
//$rsa->setPassword('layanthi#123');
extract($rsa->createKey());
//echo "$privatekey<br />$publickey";
echo $privatekeydata=$privatekey;
echo '<br />';
echo $pubkey=$publickey; //key pair genarated - ok
//encryption using pubkey - commented snippet from phpseclib
$file="word_gen\loan_docs\la_".$upfno."_".$loanid_db.".docx";
$message=file_get_contents($file);
function rsa_encrypt($key, $message) {
$rsa = new Crypt_RSA();
$rsa->loadKey($key);
$encrypted = base64_encode($rsa->encrypt($message));
return $encrypted;
}
echo $encrypt_file=rsa_encrypt($pubkey, $message);
//from here i want to save encryptted file to encrypt folder like
//$savepath="encrypt\la_".$upfno."_".$loanid_db.".docx"; but i dont know how to do that
//Deryption using phpseclib function is here - but how to use it for above encryption
function rsa_decrypt($key, $package) {
$rsa = new Crypt_RSA();
$rsa->loadKey($key);
$decrypted = $rsa->decrypt(base64_decode($package));
return $decrypted;
}

Answer 1

echo $encrypt_file=rsa_encrypt($pubkey, $message);
$savepath="word_gen\encrypt\la_".$upfno."_".$loanid_db.".docx";
file_put_contents($savepath, $encrypt_file);
//Deryption using phpseclib function is here - but how to use it for above encryption
function rsa_decrypt($key, $package) {
$rsa = new Crypt_RSA();
$rsa->loadKey($key);
$decrypted = $rsa->decrypt(base64_decode($package));
return $decrypted;
}
//get encrypt file
$encfile="word_gen\encrypt\la_".$upfno."_".$loanid_db.".docx";
$epackage=file_get_contents($encfile);
echo $decryptfile= rsa_decrypt($privatekeydata, $epackage);
$savepath_de="word_gen\decrypt\la_".$upfno."_".$loanid_db.".docx";
file_put_contents($savepath_de, $encrypt_file);
?>