[Cryptography-dev] "Streaming" APIs

[Alex Gaynor]

So I've thoguht about this some, I think the idea of using iterables in the
API makes a ton of sense, but somehow the `x` and `iter_x` names don't sit
right with me, does anyone have any better suggestions?

Alex


On Wed, Sep 11, 2013 at 7:19 PM, Donald Stufft <donald at stufft.io> wrote:

> So one thing that's really handy to do with encryption is to be able to
> (de|en)crypt things without needing to load the entire thing into memory.
> Currently we support this in the encrypt API by doing:
>
> cipher = BlockCipher()
>
> enciphered = cipher.encrypt(block1)
> enciphered += cipher.encrypt(block2)
> enciphered += cipher.encrypt(block3)
> enciphered += cipher.finalize()
>
> We needed to do this because we need to be able to call finalize() before
> the encryption is "done".
>
> When I was messing with padding I ended up with an API that (for padding)
> got around the need for an explicit finalize step but instead it required
> passing the entire data stream into the function. However it supports
> generators/iterators so you can still efficiently process large datasets.
>
> This api looks something like
>
> padder = Padding()
>
> padded1 = "".join(padder.pad("1234"))
> padded2 = "".join(padder.pad(c for c in "1234"))
>
> However the downside of this API is that You need to call "".join() to get
> actual strings or you need to do some ugly hacks inside of the pad()
> function so it returns a string if given a string and returns a generator
> if given a generator.
>
> A third option is similar to dictionaries on Python 2.x where you have
> something like iterpad() and pad(). This could work for encryption as well
> so we'd have iter_encrypt(), iter_decrypt(), encrypt() and decrypt().
>
> So I guess the question is how do we want to handle these streaming sorts
> of APIs?
>
> 1) Thing.action() + Thing.finalize()
> 2a) "".join(Thing.action(iterator))
> 2b) Thing.action(terator OR string) - Magic return types
> 3) Thing.action and Thing.iter_action
> 4) ????
>
> -----------------
> Donald Stufft
> PGP: 0x6E3CBCE93372DCFA // 7C6B 7C5D 5E2B 6356 A926 F04F 6E3C BCE9 3372
> DCFA
>
>
> _______________________________________________
> Cryptography-dev mailing list
> Cryptography-dev at python.org
> https://mail.python.org/mailman/listinfo/cryptography-dev
>
>


-- 
"I disapprove of what you say, but I will defend to the death your right to
say it." -- Evelyn Beatrice Hall (summarizing Voltaire)
"The people's good is the highest law." -- Cicero
GPG Key fingerprint: 125F 5C67 DFE9 4084
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/cryptography-dev/attachments/20130914/a097a411/attachment.html>