Add DSA about cryptography

[alex]

First hard API design question:

RSAPrivateKey objects have a public_key method which returns an RSAPublicKey. Presumably we'd like to have the same on DSAPrivateKey. Unfortunately DSA keys contain a member (y) which is also typically known by public_key.

It seems we have three choices:

• Be inconsistent with typical naming conventions around DSA
• Be inconsistent with the RSA API
• Change the RSA API as well

Opinions?

[public]

What APIs call only the bare y a public key?

Seems like public_key should return a DSAPublicKey and that y parameter should just be y to me.

[reaperhulk]

It'd be nice to store the DSA params as an object, which then makes DSAPublicKey a more useful object.

private_key = dsa.DSAPrivateKey.generate(2048, backend)
params = private_key.params()
public_key = private_key.public_key()
same_params = public_key.params()
print(params.p)
print(same_params.p)

[cipherself]

@reaperhulk agreed.

[alex]

@public We've typically tried to offer the more verbose name whenever possible here, PyCrypto's docs describe y as Public key (y), I haven't seen any other reference on this.

[cipherself]

@alex I think the to-do list needs to be updated?

[reaperhulk]

I've updated the list.

[cipherself]

@reaperhulk Awesome, thanks :)

[alex]

I guess we're done here.

[public]

High fives all round.