Add AES192 and AES256 as optional encryption methods

[tknarr]

Add AES192 and AES256 as supported encryption methods.
Add version bytes to distinguish between AES128, AES192 and AES256 encryption in tokens.

[tknarr]

Associated changes to the Ruby implementation are in closed pull requests tknarr/fernet-rb#1 and tknarr/fernet-cli#1 in my forks.

[tuupola]

Any news about this?

[brianorwhatever]

It's unfortunate this isn't getting looked at. AES128 is not good enough for modern applications and I'm sure many people would like to see this enhancement merged in.

[tknarr]

I'm wondering if the spec's even maintained.

[kennyp]

@tknarr I'll take a look at this and the related fernet-rb PR. Thanks!

[bitkeks]

Given the spec is currently pinned to AES128, will this PR move forward in the future?

It'd be good to know if Fernet keeps up with comparable specs (comparable algorithms) in regards to levels of encryption.

[clach04]

@tknarr From comments it seems like there is interest in this, but not from the official project.

Have you considered hard forking and renaming (e.g. to Anise, or something) and documenting it a superset of Fernet and thus backward compatible with the Fernet spec?

I realize your focus and goals may have changed in the last 8 year 😉

From what I read your proposed spec and Ruby code changes, look good 👍 .