RSA (PKCS1 padding) compatibility for BouncyCastle & OpenSSL

[Pada]

Hi,

I've noticed that Bouncy Castle and OpenSSL is not coded strictly according to PKCS#1 v2.1 RFC, which results in phpseclib not being able to decrypt messages encrypted with the private key. They both set the 2nd-bit to 2 when encrypting with a private key, instead of to 1 !

I have a very simple solution for this: Replace the following line in RSA.php, in the _rsaes_pkcs1_v1_5_decrypt function:

Code: Select all

if (ord($em[0]) != 0 || ord($em[1]) != 2) {

with

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$type = ord($em[1]);
if (ord($em[0]) != 0 || (($type != 1) && ($type != 2))) {

I hope that this would be helpful to others.

Regards,
Chris

* Thanks for the great PHP library. It's definitely one of the best/easiest Cryptography libraries to use that I've came across!

[TerraFrost]

I actually committed a similar fix to CVS a short time ago :

http://phpseclib.cvs.sourceforge.net/vi ... 14&r2=1.15

Anyway, thanks for the feedback!

[Pada]

Thank you very much for the fast response.

I didn't know that you included a compatibility fix, since the latest archived version of phpseclib (v0.2.0) was released like 5 Dec 2009.

It really took me (actually my colleague found it) a couple of days to figure out why my colleague's J2ME application was unable to communicate with my PHP script. Your modification should be slightly faster than mine, but you're allowing the second bit to be 0 too