Does RSA do the work right?

[blagorod]

Hi.
I had a look at the example in RSA phpseclib.

Code: Select all

<?php
include('Crypt/RSA.php');

$rsa = new Crypt_RSA();

extract($rsa->createKey());
$plaintext = 'terrafrost';
$rsa->loadKey($privatekey);
$ciphertext = $rsa->encrypt($plaintext);
$rsa->loadKey($publickey);
echo $rsa->decrypt($ciphertext);
?>


As I see it encrypts with private key. But the RSA specs tells that it should be done with public key. Check it out: http://en.wikipedia.org/wiki/RSA
Any thoughts?

[TerraFrost]

If you encrypt with the public key you decrypt with the private key and if you encrypt with the private key you decrypt with the public key.

If you're encrypting something with the private key I guess that's more analogous to signing but there are instances where you might want to do encryption too.

[robiwan]

I don't think you can encrypt with private key and decrypt with the public key to get an intelligible result, which is why RSA is called asymmetric, right ?

This procedure is useful for signing though.

[TerraFrost]

RSA is called asymmetric because it uses a different key for decrypting than it does for encrypting. A symmetric key encryption algorithm would have the same key - symmetry - on both sides. And yeah - in the case of RSA you can encrypt with one key and decrypt with the other.

[bantu]

Jim, the problem here is that the example for encrypting/decrypting with RSA at http://phpseclib.sourceforge.net/docume ... a_examples seems to use $privatekey for encryption and $publickey for decrypting. This confuses people and is probably not what you wanted to write there. I would suggest to swap the two parameters.

[bantu]

Bump.

[TerraFrost]

It's been updated - thanks!