def parse_encryption(cls, encryption, key_info):
"""Read encryption information from the <EncryptionKey> XML tree."""
if key_info is None:
return
encryption.id = key_info.get('Id')
encryption.algorithm = (
key_info.get('Algorithm') or
key_info.get('algorithm') or
encryption.algorithm)
for name in findall(key_info,
'KeyName', 'DerivedKey/MasterKeyName',
'DerivedKey/CarriedKeyName'):
encryption.key_names.append(findtext(name, '.'))
encryption.iv = findbin(key_info, 'IV') or encryption.iv
cls.parse_key_derivation(encryption.derivation, find(
key_info, 'DerivedKey/KeyDerivationMethod'))
encryption.derivation.pbkdf2_salt = (
findbin(key_info, 'PBESalt') or encryption.derivation.pbkdf2_salt)
encryption.derivation.pbkdf2_iterations = (
findint(key_info, 'PBEIterationCount') or
encryption.derivation.pbkdf2_iterations)
algorithm = (
key_info.get('Algorithm') or key_info.get('algorithm') or '')
if (algorithm.lower().startswith('pbe') and
not encryption.derivation.algorithm):
encryption.derivation.algorithm = 'pbkdf2'
encryption.derivation.pbkdf2_key_length = (
encryption.derivation.pbkdf2_key_length or
encryption.algorithm_key_lengths[0])
def parse_key_derivation(cls, derivation, key_derivation):
"""Read derivation parameters from a <KeyDerivationMethod> element."""
if key_derivation is None:
return
derivation.algorithm = key_derivation.get('Algorithm')
# PBKDF2 properties
pbkdf2 = find(key_derivation, 'PBKDF2-params')
if pbkdf2 is not None:
# get used salt
derivation.pbkdf2_salt = findbin(pbkdf2, 'Salt/Specified')
# required number of iterations
derivation.pbkdf2_iterations = findint(pbkdf2, 'IterationCount')
# key length
derivation.pbkdf2_key_length = findint(pbkdf2, 'KeyLength')
# pseudorandom function used
prf = find(pbkdf2, 'PRF')
if prf is not None:
derivation.pbkdf2_prf = prf.get('Algorithm')
def parse(self, key_deriviation):
"""Read derivation parameters from a <KeyDerivationMethod> element."""
from pskc.xml import find, findint, findbin
if key_deriviation is None:
return
self.algorithm = key_deriviation.get('Algorithm')
# PBKDF2 properties
pbkdf2 = find(
key_deriviation, 'xenc11:PBKDF2-params', 'pkcs5:PBKDF2-params')
if pbkdf2 is not None:
# get used salt
self.pbkdf2_salt = findbin(
pbkdf2, 'Salt/Specified', 'xenc11:Salt/xenc11:Specified')
# required number of iterations
self.pbkdf2_iterations = findint(
pbkdf2, 'IterationCount', 'xenc11:IterationCount')
# key length
self.pbkdf2_key_length = findint(
pbkdf2, 'KeyLength', 'xenc11:KeyLength')
# pseudorandom function used
prf = find(pbkdf2, 'PRF', 'xenc11:PRF')
if prf is not None:
self.pbkdf2_prf = prf.get('Algorithm')
def parse_policy(cls, policy, policy_elm):
"""Read key policy information from the provided <Policy> tree."""
if policy_elm is None:
return
policy.start_date = findtime(policy_elm, 'StartDate')
policy.expiry_date = findtime(policy_elm, 'ExpiryDate')
policy.number_of_transactions = findint(
policy_elm, 'NumberOfTransactions')
for key_usage in findall(policy_elm, 'KeyUsage'):
policy.key_usage.append(findtext(key_usage, '.'))
pin_policy_elm = find(policy_elm, 'PINPolicy')
if pin_policy_elm is not None:
policy.pin_key_id = pin_policy_elm.get('PINKeyId')
policy.pin_usage = pin_policy_elm.get('PINUsageMode')
policy.pin_max_failed_attempts = getint(
pin_policy_elm, 'MaxFailedAttempts')
policy.pin_min_length = getint(pin_policy_elm, 'MinLength')
policy.pin_max_length = getint(pin_policy_elm, 'MaxLength')
policy.pin_encoding = pin_policy_elm.get('PINEncoding')
# check for child elements
if list(pin_policy_elm):
policy.unknown_policy_elements = True
# check for unknown attributes
known_attributes = set([
'PINKeyId', 'PINUsageMode', 'MaxFailedAttempts', 'MinLength',
'MaxLength', 'PINEncoding'])
if set(pin_policy_elm.keys()) - known_attributes:
policy.unknown_policy_elements = True
# check for other child elements
known_children = set([
'StartDate', 'ExpiryDate', 'NumberOfTransactions', 'KeyUsage',
'PINPolicy'])
for child in policy_elm:
if child.tag not in known_children:
policy.unknown_policy_elements = True
def parse(self, policy):
"""Read key policy information from the provided <Policy> tree."""
from pskc.xml import (
find, findall, findtext, findint, findtime, getint)
if policy is None:
return
self.start_date = findtime(policy, 'pskc:StartDate')
self.expiry_date = findtime(policy, 'pskc:ExpiryDate')
self.number_of_transactions = findint(
policy, 'pskc:NumberOfTransactions')
for key_usage in findall(policy, 'pskc:KeyUsage'):
self.key_usage.append(findtext(key_usage, '.'))
pin_policy = find(policy, 'pskc:PINPolicy')
if pin_policy is not None:
self.pin_key_id = pin_policy.get('PINKeyId')
self.pin_usage = pin_policy.get('PINUsageMode')
self.pin_max_failed_attemtps = getint(
pin_policy, 'MaxFailedAttempts')
self.pin_min_length = getint(pin_policy, 'MinLength')
self.pin_max_length = getint(pin_policy, 'MaxLength')
self.pin_encoding = pin_policy.get('PINEncoding')
