malemburg
commented
8 years ago I propose to deprecate os.urandom() altogether due to all the issues we've discussed on all those recent tickets, see e.g. bpo-26839, bpo-27250, bpo-25420.
Unlike what we've told people for many years, it's clear that in the age of VMs/containers getting booted/started every few seconds, it's not longer the generic correct answer to people asking for random data, since it doesn't make a difference between crypto random and pseudo random data.
By far most use cases only need pseudo random data and only very few applications require crypto random data.
Instead, let's define something everybody can start to use correctly and get sane behavior on most if not all platforms. As Larry suggested in bpo-27266, getrandom() is a good starting point for this, since it's adoption is spreading fast and it provides the necessary features we need for the two new APIs.
I propose these new APIs:
-
random.cryptorandom() for getting OS crypto random data
-
random.pseudorandom() for getting OS pseudo random data
Crypto applications will then clearly know that random.cryptorandom() is the right choice for them and everyone else can use random.pseudorandom().
random.cryptorandom() will guarantee that the returned data is safe for crypto applications on all platforms, blocking or raising an exception if necessary to make sure only safe data is returned. The API should get a parameter to determine whether to raise or block.
random.pseudorandom() will guarantee to not block and always return random data that can be used as seeds for simulations, games, tests, monte carlo, etc.
The APIs should use the getrandom() C API, where available, with appropriate default settings, i.e. blocking or raising for random.cryptorandom() and non-blocking, non-raising for random.pseudorandom().
The existing os.urandom() would then be deprecated to guide new developments to the these new APIs, getting rid of the ambiguities and problems this interface has on several platforms (see all the other tickets and https://en.wikipedia.org/wiki//dev/random for details).
tiran
larryhastings
ncoghlan
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields: ```python assignee = None closed_at =
created_at =
labels = ['type-feature', 'library']
title = 'Add random.cryptorandom() and random.pseudorandom, deprecate os.urandom()'
updated_at =
user = 'https://github.com/malemburg'
```
bugs.python.org fields:
```python
activity =
actor = 'ncoghlan'
assignee = 'none'
closed = True
closed_date =
closer = 'ncoghlan'
components = ['Library (Lib)']
creation =
creator = 'lemburg'
dependencies = []
files = []
hgrepos = []
issue_num = 27279
keywords = []
message_count = 12.0
messages = ['267970', '267972', '267977', '267978', '267983', '267991', '267995', '268005', '268010', '268014', '268038', '274711']
nosy_count = 3.0
nosy_names = ['lemburg', 'ncoghlan', 'larry']
pr_nums = []
priority = 'normal'
resolution = 'rejected'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue27279'
versions = ['Python 3.6']
```