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siphash - python siphash implementation

Project description

pysiphash
====

A Python implementation of [SipHash](https://131002.net/siphash/), a
fast short-input PRF.

Extract from the description:

```
SipHash is a family of pseudorandom functions (a.k.a. keyed hash
functions) optimized for speed on short messages.

Target applications include network traffic authentication and defense
against hash-flooding DoS attacks.

SipHash is secure, fast, and simple (for real):
* SipHash is simpler and faster than previous cryptographic algorithms
(e.g. MACs based on universal hashing)
* SipHash is competitive in performance with insecure
non-cryptographic algorithms (e.g. MurmurHash)
* We propose that hash tables switch to SipHash as a hash
function. Users of SipHash already include OpenDNS, Perl 5, Ruby, or
Rust.
```

usage
----

`Pysiphash` tries to follow the
[hashlib](http://docs.python.org/2/library/hashlib.html) API. You can
add data to the hash by calling an `update` method, or feed data
directly to the constructor:

```:python
>>> import siphash
>>> key = '0123456789ABCDEF'
>>> sip = siphash.SipHash_2_4(key)
>>> sip.update('a')
>>> sip.hash()
12398370950267227270L

>>> siphash.SipHash_2_4(key, 'a').hash()
12398370950267227270L
```

To extract the hash as a numeric value call `hash()`:

```
>>> siphash.SipHash_2_4(key, 'a').hash()
12398370950267227270L
```

Or `digest()` to get a raw 8-bytes string:
```:python
>>> siphash.SipHash_2_4(key, 'a').digest()
'\x86L3\x9c\xb0\xdc\x0f\xac'
```

Or `hexdigest()` for a 16-bytes hex encoding:
```:python
>>> siphash.SipHash_2_4(key, 'a').hexdigest()
'864c339cb0dc0fac'
```

testing
----

A series of sanity checks are present inline the main `pysiphash`
code, to run it type:

```:bash
$ python siphash/__init__.py
all tests ok
```

speed
----

Currently `pysiphash` is a pure-python code, so don't expect blazing
speed. On my machine computing a hash from a ten byte string takes
around 0.31 ms, and hashing 1MiB blob takes 770 ms.

Project details


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