[issue15206] uuid module falls back to unsuitable RNG

[STINNER Victor]

STINNER Victor <victor.stinner at gmail.com> added the comment:

> However a MT isn't suitable for cryptographic purposes.
> The module should first try to use os.urandom() and
> then perhaps use its own instance of random.Random,
> similar to uuid_generate_* [1]

os.urandom() is not suitable for cryptographic purposes :-) Python 3.3 has also ssl.RAND_bytes() which is better than os.urandom(), but it's not possible (easy?) to build a custom random.Random class with an arbitrary RNG (like os.urandom or ssl.RAND_bytes).

It would be nice to provide an API to choose the best RNG depending on a set of requirements. I wrote the Hasard library which implements such idea: the library provides "profiles" and chooses the best RNG for a profile. Profiles:
- fast
- secure nonblocking
- secure blocking
- hardware

See the doc directory the Hasard project for details:
https://bitbucket.org/haypo/hasard/
https://bitbucket.org/haypo/hasard/src/82d13450c552/doc/profile_list.rst

See also the issue #12858 for another user of a better RNG.

I'm quite sure that all these RNG issues are a good candidate for a PEP because RNG is complex problem, there are different use cases, various implements, and a lot of common issue (in RNG implementations). Handling fork or not is an important question, which impact performances, for example.

See also the issue #12754: "Add alternative random number generators".

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nosy: +haypo

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