[PYTHON-CRYPTO] PyCrypto Draft: Proposal 2001-02-18

[Michael Ströder]

Andrew Archibald wrote:
>
> machine = PyCrypto.registry.getInstance("blowfish")(mode=PyCrypto.block.CBC,
>                                                     IV=my_iv,
>                                                     key="seekrit")
>
> Or, I suppose:
>
> blowfish = PyCrypto.regstry.getInstance("blowfish")
> machine = blowfish(mode=blowfish.CBC, IV=my_iv, key="seekrit")

Actually it's PyCrypto.getInstance(). I will just provide an extra
PyCrypto.getClass() to make everyone happy.

> Questions I have:
> What should be done about algorithms that have no OID yet?  Pick a
> random one?

Several options:
- Use unique string names to register (good for testing).
- Use private OID arc for testing (good for testing).
- Use a registered OID arc for assigning authorized OIDs.

> How hard is it to find ASN.1 OIDs for known algorithms?

Peter Gutmann is maintaining a config file for his dumpasn1 tool:

  http://www.cs.auckland.ac.nz/~pgut001/dumpasn1.cfg

It's the most complete and clean list I know of.

> In your algorithm categories, is "Ciphers" supposed to cover both
> symmetric and asymmetric algorithms?

Yes. But it's just the base class. Separate derived classes
AsymmetricCipher(Cipher) and SymmetricCipher(Cipher) are defined.

>  Is "Hashes" supposed to cover
> both keyed and unkeyed hashes?

Yes. Feel free to give me reasons to separate it. Note: I focused on
the load mechanism.

> If we provide a registerImplementation method, we should also provide
> an unregisterImplementation method --- If I disintall openSSL because
> it has a security hole, all my Python applications shouldn't start
> dying.

I don't know how to do that. If your applications are running and
were using OpenSSL it seems unpossible for me to deinstall OpenSSL
without messing up the applications.

> An alternative would be to scan the directory structure on demand.

This imposes strong rules to the directory layout of implementations
which I'd like to avoid.

Ciao, Michael.