Files
pysim/contrib/csv-encrypt-columns.py
Harald Welte 1aaf978d9f CardKeyProvider: Implement support for column-based transport key encryption
It's generally a bad idea to keep [card specific] key material lying
around unencrypted in CSV files.  The industry standard solution in the
GSMA is a so-called "transport key", which encrypts the key material.

Let's introduce support for this in the CardKeyProvider (and
specifically, the CardKeyProviderCSV) and allow the user to specify
transport key material as command line options to pySim-shell.

Different transport keys can be used for different key materials, so
allow specification of keys on a CSV-column base.

The higher-level goal is to allow the CSV file not only to store
the ADM keys (like now), but also global platform key material for
establishing SCP towards various security domains in a given card.

Change-Id: I13146a799448d03c681dc868aaa31eb78b7821ff
2024-06-04 23:18:37 +02:00

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2.9 KiB
Python
Executable File

#!/usr/bin/env python3
# Utility program to perform column-based encryption of a CSV file holding SIM/UICC
# related key materials.
#
# (C) 2024 by Harald Welte <laforge@osmocom.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import sys
import csv
import argparse
from Cryptodome.Cipher import AES
from pySim.utils import h2b, b2h, Hexstr
from pySim.card_key_provider import CardKeyProviderCsv
def dict_keys_to_upper(d: dict) -> dict:
return {k.upper():v for k,v in d.items()}
class CsvColumnEncryptor:
def __init__(self, filename: str, transport_keys: dict):
self.filename = filename
self.transport_keys = dict_keys_to_upper(transport_keys)
def encrypt_col(self, colname:str, value: str) -> Hexstr:
key = self.transport_keys[colname]
cipher = AES.new(h2b(key), AES.MODE_CBC, CardKeyProviderCsv.IV)
return b2h(cipher.encrypt(h2b(value)))
def encrypt(self) -> None:
with open(self.filename, 'r') as infile:
cr = csv.DictReader(infile)
cr.fieldnames = [field.upper() for field in cr.fieldnames]
with open(self.filename + '.encr', 'w') as outfile:
cw = csv.DictWriter(outfile, dialect=csv.unix_dialect, fieldnames=cr.fieldnames)
cw.writeheader()
for row in cr:
for key_colname in self.transport_keys:
if key_colname in row:
row[key_colname] = self.encrypt_col(key_colname, row[key_colname])
cw.writerow(row)
if __name__ == "__main__":
parser = argparse.ArgumentParser()
parser.add_argument('CSVFILE', help="CSV file name")
parser.add_argument('--csv-column-key', action='append', required=True,
help='per-CSV-column AES transport key')
opts = parser.parse_args()
csv_column_keys = {}
for par in opts.csv_column_key:
name, key = par.split(':')
csv_column_keys[name] = key
if len(csv_column_keys) == 0:
print("You must specify at least one key!")
sys.exit(1)
csv_column_keys = CardKeyProviderCsv.process_transport_keys(csv_column_keys)
for name, key in csv_column_keys.items():
print("Encrypting column %s using AES key %s" % (name, key))
cce = CsvColumnEncryptor(opts.CSVFILE, csv_column_keys)
cce.encrypt()