[pycrypto] DES/DES3/XOR/etc removal
reikon at reikon.us
Wed Apr 22 15:26:31 CST 2009
Jean-Paul Calderone wrote:
> On Wed, 22 Apr 2009 17:05:20 -0400, Thomas Dixon <reikon at reikon.us> wrote:
>> Tzury Bar Yochay wrote:
>>> please keep the DES3 and XOR.
>>> we use them and need them in our ongoing projects
>>> On Wed, Apr 22, 2009 at 8:23 PM, Jean-Paul Calderone
>>> <exarkun at twistedmatrix.com <mailto:exarkun at twistedmatrix.com>> wrote:
>>> Someone pointed out that XOR and several other ciphers  have been
>>> removed from PyCrypto. This has the consequence that Twisted Conch,
>>> and SSH client and server implementation which depends on PyCrypto,
>>> no longer works with the latest development version of PyCrypto, and
>>> I assume that when the next release of PyCrypto is made, Conch also
>>> won't work with that.
>>> I'm curious how important backwards compatibility is deemed with the
>>> new PyCrypto development going on. A change like the one referenced
>>> above is going to break users of PyCrypto (and that seems like it is
>>> really obvious, to me - as opposed to a change which only accidentally
>>> breaks applications). The added maintenance burden this causes makes
>>> PyCrypto less attractive (one nice thing about PyCrypto having been
>>> unmaintained for a long time is that Conch's use of it stayed as
>>> correct (or incorrect) as it was when it was written). Basically, the
>>> question is whether I should expect more PyCrypto changes like this
>>> as development proceeds, or whether I can make the argument that
>>> compatibility is a *good* thing compelling.
>>> Of course it's one thing to say "more backwards compatibility please".
>>> Actually deciding how that can be accomplished while allowing
>>> to proceed in a useful direction is another. However, I'm
>>> omitting details of that discussion from this message to keep things
>>> simple. I'm convinced that some degree of backwards compatibility is
>>> always possible, regardless of the changes desired, so the details
>>> of how
>>> it works aren't as important as deciding whether backwards
>>> will be maintained.
>>> So, what do you say? Can we decide that backwards compatibility
>>> is a good
>>>  -
>>> pycrypto mailing list
>>> pycrypto at lists.dlitz.net <mailto:pycrypto at lists.dlitz.net>
>>> pycrypto mailing list
>>> pycrypto at lists.dlitz.net
>> Personally, if Dwayne has decided to remove Blowfish, DES, 3DES, RC5,
>> IDEA, and XOR, then I agree with that decision completely. From a legal
>> and security standpoint, it makes perfect sense. There's also nothing to
>> say that Dwayne won't add different implementations of some of these
>> algorithms back into PyCrypto's offerings at a later date.
> Great. If that's the plan, then my complaint is moot. My concern is
> that the next release of PyCrypto won't have these APIs.
> I understand that there are legal issues, but they're not new - PyCrypto
> has had whatever they are for almost a decade - maybe *more* than a decade,
> I dunno. I'm all for resolving them, but I don't think the resolution needs
> to be immediate, given that it is going to break things. Go ahead and
> deprecate the APIs with implementations that are not licensed compatibly
> with the rest of PyCrypto, and even remove them after having deprecated
> them for a while. But don't just delete them without warning and surprise
> all the application developers relying on them. Again, if the plan is to
> restore these APIs with new implementations, great, I'll stop complaining.
>> Those who will primarily suffer from a software developer's laziness are
>> their users.
> I don't know what you mean by this.
> pycrypto mailing list
> pycrypto at lists.dlitz.net
I don't see how he's deleting anything without warning. You *are*
referring to a *development* version, are you not? How do you know he
doesn't plan to replace some of the implementations he removed with
different implementations prior to the next release?
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