SipHash

0.0.1 verified Fri May 01 auth: no python

A pure Python implementation of SipHash, a fast short-input PRF. Version 0.0.1 is the latest and only release; no active development.

pip install siphash

Common errors

error TypeError: a bytes-like object is required, not 'str' ↓

cause Message passed as string instead of bytes.

fix

Use msg = 'hello'.encode('utf-8')

error ValueError: Key must be exactly 16 bytes long ↓

cause Key length is not 16 bytes.

fix

Ensure key is 16 bytes: key = b'sixteenbyteslong'

Warnings

gotcha Key must be exactly 16 bytes; any other length raises ValueError. ↓

fix Ensure key length is 16.

gotcha SipHash_2_4 and SipHash_1_3 are the only variants; no 8-round or 4-round versions. ↓

fix Use SipHash_2_4 for default security.

gotcha Input message must be bytes; passing str will cause TypeError. ↓

fix Encode strings before hashing: msg.encode('utf-8')

Imports

SipHash_2_4
```
from siphash import SipHash_2_4
```
Correct, though SipHash_2_4 is a class; there is also SipHash_1_3.

Quickstart

Setup key and message, then call instance to get 64-bit hash.

from siphash import SipHash_2_4

key = b'\x00' * 16  # 128-bit key
msg = b'hello'

siphash = SipHash_2_4(key)
digest = siphash(msg)
print(digest.hex())  # 64-bit digest