RSA keys of 2048 bits or more can't be saved or loaded

[jarto]

Saving a RSA key of 2048 bits or more does work, but loading the key gives errors.
It's still unclear where the problem is. So far I've verified that the big keys do work: Encrypting with a big public key works as well as decrypting the message with the private key.

[PizzaProgram]

Hi,
Is this problem resolved since 2013?

We need to implement JSON Web Signature (JWS) under Lazarus, and for that RSA 4096bit signing.

[jarto]

As far as I know, this has not been resolved. I'd be happy to merge a fix from someone who still uses this library and who knows where the problem is.

[PizzaProgram]

I've looked into the code and searched for older code too.
From those I know, that back in 2013 there was only 1024bit allowed.
Later they've added 2048 + 3072 bits. Link:

lockbox2/source/LbRSA.pas

Line 80 in 4a35af5

TRSACipherBlock3072 = array[0..cBytes3072-1] of Byte;

But 4096 is still missing! :(

[jarto]

In that case it should be pretty easy to fix this issue. If you can't do it yourself, maybe you could contact Todd who did the previous fix? I'm not using LockBox any more myself. The original fixes and improvements I did when I needed to use LockBox in 64bit environment.