Encrypt in Javascript, decrypt in PHP, using public-key cryptography

Question

I\'d like to encrypt in JavaScript, decrypt in PHP, using public-key cryptography. I\'ve been trying to find libraries that can accomplish this, but am having issues.

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Answer 1

I've used something similar for my login page; it encrypts login credentials using the given public key information (N, e) which can be decrypted in PHP.

It uses the following files that are part of JSBN:

• jsbn.js - to work with big integers
• rsa.js - for RSA encryption only (uses jsbn.js)
• rng.js - basic entropy collector
• prng4.js - ARC4 RNG backend

To encrypt data:

$pk = '-----BEGIN RSA PRIVATE KEY-----
...
-----END RSA PRIVATE KEY-----';
$kh = openssl_pkey_get_private($pk);
$details = openssl_pkey_get_details($kh);

function to_hex($data)
{
    return strtoupper(bin2hex($data));
}

?>

This is how you would decode the sent data:

$kh = openssl_pkey_get_private($pk);
$details = openssl_pkey_get_details($kh);
// convert data from hexadecimal notation
$data = pack('H*', $data);
if (openssl_private_decrypt($data, $r, $kh)) {
   echo $r;
}