# -*- coding: utf-8 -*-
"""The SHA-256 Hasher implementation."""
import hashlib
from plaso.analyzers.hashers import interface
from plaso.analyzers.hashers import manager
[docs]
class SHA256Hasher(interface.BaseHasher):
"""This class provides SHA-256 hashing functionality."""
NAME = 'sha256'
ATTRIBUTE_NAME = 'sha256_hash'
DESCRIPTION = 'Calculates a SHA-256 digest hash over input data.'
[docs]
def __init__(self):
"""Initializes the SHA-256 hasher."""
super(SHA256Hasher, self).__init__()
self._sha256_context = hashlib.sha256()
[docs]
def GetStringDigest(self):
"""Returns the digest of the hash function expressed as a Unicode string.
Returns:
str: string hash digest calculated over the data blocks passed to
Update(). The string consists of printable Unicode characters.
"""
return self._sha256_context.hexdigest()
[docs]
def Update(self, data):
"""Updates the current state of the hasher with a new block of data.
Repeated calls to update are equivalent to one single call with the
concatenation of the arguments.
Args:
data(bytes): block of data with which to update the context of the hasher.
"""
self._sha256_context.update(data)
manager.HashersManager.RegisterHasher(SHA256Hasher)