RSA encryption doesn't actually use RSAES-OAEP + MGF1+SHA256(?)

[M-FF-M]

I wrote a Java library compatible with EasyRSA. It is working but I had to change the code of the function getRsa (line 39 in EasyRSA.php) - I added the following lines: after line 44: $rsa->setHash('sha256'); after line 47: $rsa->setEncryptionMode($mode);

Before adding those lines, I wasn't able to decrypt the RSA part with Java, but after adding them I could decrypt the RSA part with algorithm "RSA/ECB/OAEPWithSHA-256AndMGF1Padding".

So, my question is: Is the code in EasyRSA.php wrong or is it supposed to be different from Java algorithm "RSA/ECB/OAEPWithSHA-256AndMGF1Padding"?

[M-FF-M]

Just to be sure, I checked my code again - it's actually not necessary to add the line $rsa->setEncryptionMode($mode); to make the RSA encryption compatible with Java's "RSA/ECB/OAEPWithSHA-256AndMGF1Padding", you only have to add $rsa->setHash('sha256').

Thus, I think my last post is irrelevant (as I can't say which hashing algorithm is supposed to be used in connection with RSA from the comments in the source code).

[paragonie-scott]

I wrote a Java library compatible with EasyRSA

EasyRSA is never meant to be compatible with anything except itself. If you need cross-platform compatibility, please use libsodium instead.

[M-FF-M]

EasyRSA is never meant to be compatible with anything except itself. If you need cross-platform compatibility, please use libsodium instead.

I would if I could. But it's only a private project anyway (more for fun and to get familiar with the most common encryption algorithms than for real security).

[paragonie-scott]

That's fine, but:

What's stopping you from using libsodium? It being a private project doesn't tell me much. If it's the inability to install PHP extensions in your production environment, see https://github.com/paragonie/sodium_compat for a polyfill.

[M-FF-M]

Great, I didn't know about the polyfill. I read an article somewhere (I can't remember where exactly) which said that you have to install a PHP extension to use libsodium and EasyRSA.php was actually mentioned as an alternative if you coudn't install extensions. That's why I was trying to use EasyRSA.php.

I will use libsodium now, thanks!

PS: It was still a nice exercise to write a EasyRSA.php-compatible Java library even though I probably commited a lot of security mistakes I don't know about.

[paragonie-scott]

I might need to update one of our older blog posts, it sounds like something I wrote last year.

PS: It was still a nice exercise to write a EasyRSA.php-compatible Java library even though I probably commited a lot of security mistakes I don't know about.

100% agreed. http://www.cryptofails.com/post/75204435608/write-crypto-code-dont-publish-it

[jimmykane]

Yep. It's that blog post. I reached here via that blog post. Thanks

On Thu, Aug 31, 2017, 4:43 PM Scott notifications@github.com wrote:

I might need to update one of our older blog posts, it sounds like something I wrote last year.

PS: It was still a nice exercise to write a EasyRSA.php-compatible Java library even though I probably commited a lot of security mistakes I don't know about.

100% agreed. http://www.cryptofails.com/post/75204435608/write-crypto-code-dont-publish-it

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