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Added some documentation

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git-svn-id: https://vsmartcard.svn.sourceforge.net/svnroot/vsmartcard@482 96b47cad-a561-4643-ad3b-153ac7d7599c
This commit is contained in:
oepen
2011-08-08 11:17:05 +00:00
parent 0fdb1004eb
commit 227b684db8
1 changed files with 24 additions and 2 deletions
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26
virtualsmartcard/src/vpicc/virtualsmartcard/SEutils.py
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@@ -24,6 +24,12 @@ from virtualsmartcard.utils import inttostring
from virtualsmartcard.SWutils import SwError, SW
class ControlReferenceTemplate:
"""
Control Reference Templates are used to configure the Security Environments.
They specifiy which algorithms to use in which mode of operation and with
which keys. There are six different types of Control Reference Template:
HT, AT, KT, CCT, DST, CT-sym, CT-asym.
"""
def __init__(self, tag, config=""):
"""
Generates a new CRT
@@ -51,19 +57,30 @@ class ControlReferenceTemplate:
self.__config_string = config
def parse_SE_config(self, config):
"""
Parse a control reference template as given e.g. in an MSE APDU.
@param config : a TLV string containing the configuration for the CRT.
"""
structure = TLVutils.unpack(config)
for tlv in structure:
tag, length, value = tlv
if tag == 0x80:
self.__set_algo(value)
elif tag in (0x81, 0x82, 0x83, 0x84):
self.__set_key(tag, length, value)
self.__set_key(tag, value)
elif tag in range(0x85, 0x93):
self.__set_iv(tag, length, value)
elif tag == 0x95:
self.usage_qualifier = value
def __set_algo(self, data):
"""
Set the algorithm to be used by this CRT. The algorithms are specified
in a global dictionary. New cards may add or modify this table in order
to support new or different algorithms.
@param data: reference to an algorithm
"""
if not ALGO_MAPPING.has_key(data):
raise SwError(SW["ERR_REFNOTUSABLE"])
else:
@@ -71,7 +88,7 @@ class ControlReferenceTemplate:
self.algorithm = ALGO_MAPPING[data]
self.__replace_tag(0x80, data)
def __set_key(self, tag, length, value):
def __set_key(self, tag, value):
if tag == 0x81:
self.fileref = value
elif tag == 0x82:
@@ -105,6 +122,11 @@ class ControlReferenceTemplate:
self.iv = iv
def __replace_tag(self, tag, data):
"""
Adjust the config string using a given tag, value combination. If the
config string already contains a tag, value pair for the given tag,
replace it. Otherwise append tag, length and value to the config string.
"""
position = 0
while self.__config_string[position:position+1] != tag and position < len(self.__config_string):
length = inttostring(self.__config_string[position+1:position+2])