[Cryptography-dev] Using EC Point arithemtic in cryptography

[Alex Gaynor]

Nope, we don't have a public API for modular inverse.

Alex

On Fri, Dec 1, 2017 at 5:38 PM, John Pacific <me at johnpacific.com> wrote:

> Hey, Alex!
>
> Thanks for the response! I've been using the ECDH API for the scalar
> multiplication, but my last remaining need is for `BN_mod_inverse` and I
> can't seem to find anything on that quite yet. No pointers here, I guess?
>
>
> Thanks!
>
> -John
>
> On Fri, Dec 1, 2017 at 3:24 PM, Alex Gaynor <alex.gaynor at gmail.com> wrote:
>
>> Hi John,
>>
>> We don't have an API for doing raw EC point arithmetic.
>> https://github.com/pyca/cryptography/pull/2919 is an issue proposing
>> (and implementing) it, but I've been very hesitant to expand the API like
>> this.
>>
>> Point multiplication can be accomplished with the ECDH API.
>>
>> Alex
>>
>> On Fri, Dec 1, 2017 at 2:47 PM, John Pacific <me at johnpacific.com> wrote:
>>
>>> Hey, folks!
>>>
>>> I'm working on prototyping this cryptosystem using cryptography. I'm
>>> porting it from Charm-crypto in Python to this.
>>>
>>> Charm crypto overrides some operators to perform scalar multiplication
>>> and modular inverses -- ie: `*` and `~`. When these operators are used with
>>> an EC element, it performs the overriden operation.
>>>
>>> I am now in the need to perform some similar operations within the
>>> context of cryptography.io and I can't seem to find a great way to do
>>> this.
>>>
>>> I can access some OpenSSL functions like `EC_POINT_mul` and
>>> `BN_mod_inverse` via `default_backend()._lib.EC_POINT_mul`, etc but I
>>> can't find any documentation of how this is used within the context of
>>> cryptography.io.
>>>
>>> Do any of you wonderful folks have any pointers on this or maybe how to
>>> perform some point arithmetic with the cryptography objects?
>>>
>>>
>>> Thanks,
>>>
>>> tux
>>>
>>> _______________________________________________
>>> 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: D1B3 ADC0 E023 8CA6
>>
>>
>> _______________________________________________
>> Cryptography-dev mailing list
>> Cryptography-dev at python.org
>> https://mail.python.org/mailman/listinfo/cryptography-dev
>>
>>
>
> _______________________________________________
> 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: D1B3 ADC0 E023 8CA6
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/cryptography-dev/attachments/20171201/4a2855fc/attachment-0001.html>