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#
# This file is part of pysnmp software.
#
# Copyright (c) 2005-2019, Ilya Etingof <etingof@gmail.com>
# License: http://snmplabs.com/pysnmp/license.html
#
from hashlib import md5
from hashlib import sha1
from pyasn1.type import univ
def hashPassphrase(passphrase, hashFunc):
passphrase = univ.OctetString(passphrase).asOctets()
hasher = hashFunc()
ringBuffer = passphrase * (64 // len(passphrase) + 1)
ringBufferLen = len(ringBuffer)
count = 0
mark = 0
while count < 16384:
e = mark + 64
if e < ringBufferLen:
hasher.update(ringBuffer[mark:e])
mark = e
else:
chunk = ringBuffer[mark:ringBufferLen]
chunk += ringBuffer[0:e - ringBufferLen]
hasher.update(chunk)
mark = e - ringBufferLen
count += 1
digest = hasher.digest()
return univ.OctetString(digest)
def passwordToKey(passphrase, snmpEngineId, hashFunc):
return localizeKey(
hashPassphrase(passphrase, hashFunc), snmpEngineId, hashFunc)
def localizeKey(passKey, snmpEngineId, hashFunc):
passKey = univ.OctetString(passKey).asOctets()
# noinspection PyDeprecation,PyCallingNonCallable
digest = hashFunc(passKey + snmpEngineId.asOctets() + passKey).digest()
return univ.OctetString(digest)
# RFC3414: A.2.1
def hashPassphraseMD5(passphrase):
return hashPassphrase(passphrase, md5)
# RFC3414: A.2.2
def hashPassphraseSHA(passphrase):
return hashPassphrase(passphrase, sha1)
def passwordToKeyMD5(passphrase, snmpEngineId):
return localizeKey(hashPassphraseMD5(passphrase), snmpEngineId, md5)
def passwordToKeySHA(passphrase, snmpEngineId):
return localizeKey(hashPassphraseMD5(passphrase), snmpEngineId, sha1)
def localizeKeyMD5(passKey, snmpEngineId):
return localizeKey(passKey, snmpEngineId, md5)
def localizeKeySHA(passKey, snmpEngineId):
return localizeKey(passKey, snmpEngineId, sha1)
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