gostcrypto 1.2.4

GOST cryptographic functions

The package implements various cryptographic functions defined in the State standards of the Russian Federation. It includes the following modules:

• gosthash: The module implements functions for calculating hash amounts in accordance with GOST R 34.11-2012.

• gostcipher: The module implements block encryption functions in accordance with GOST R 34.12-2015 and their use modes in accordance with GOST R 34.13-2015.

• gostsignature: The module implements the functions of forming and verifying an electronic digital signature in accordance with GOST R 34.10-2012.

• gostrandom: The module implements functions for generating pseudo-random sequences in accordance with R 1323565.1.006-2017.

• gosthmac: The module implements the functions of calculating the HMAC message authentication code in accordance with R 50.1.113-2016.

• gostpbkdf: The module implements the password-based key derivation function in accordance with R 50.1.111-2016.

• gostoid: The module implements generating identifiers for cryptographic objects.

Installation

$ pip install gostcrypto

Usage gosthash module

Getting a hash for a string

import gostcrypto

hash_string = u'Се ветри, Стрибожи внуци, веютъ с моря стрелами на храбрыя плъкы Игоревы'.encode('cp1251')
hash_obj = gostcrypto.gosthash.new('streebog256', data=hash_string))
hash_result = hash_obj.hexdigest()

Getting a hash for a file

In this case the ‘buffer_size’ value must be a multiple of the ‘block_size’ value.

import gostcrypto

file_path = 'hash_file.txt'
buffer_size = 128
hash_obj = gostcrypto.gosthash.new('streebog512')
with open(file_path, 'rb') as file:
    buffer = file.read(buffer_size)
    while len(buffer) > 0:
        hash_obj.update(buffer)
        buffer = file.read(buffer_size)
hash_result = hash_obj.hexdigest()

Getting the name identifier of the hashing algorithm object

import gostcrypto

hash_obj = gostcrypto.gosthash.new('streebog512')
oid_name = hash_obj.oid.name

Usage gostcipher module

String encryption in ECB mode

import gostcrypto

key = bytearray([
    0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
    0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
])

plain_text = bytearray([
    0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x00, 0xff, 0xee, 0xdd, 0xcc, 0xbb, 0xaa, 0x99, 0x88,
    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xee, 0xff, 0x0a,
    0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xee, 0xff, 0x0a, 0x00,
    0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xee, 0xff, 0x0a, 0x00, 0x11,
])

cipher_obj = gostcrypto.gostcipher.new('kuznechik',
                                        key,
                                        gostcrypto.gostcipher.MODE_ECB,
                                        pad_mode=gostcrypto.gostcipher.PAD_MODE_1)

cipher_text = cipher_obj.encrypt(plain_text)

File encryption in CTR mode

In this case the ‘buffer_size’ value must be a multiple of the ‘block_size’ value.

import gostcrypto

key = bytearray([
    0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
    0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
])

init_vect = bytearray([
    0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xce, 0xf0,
])

plain_file_path = 'plain_file.txt'
cipher_file_path = 'cipher_file.txt'
cipher_obj = gostcrypto.gostcipher.new('kuznechik',
                                        key,
                                        gostcrypto.gostcipher.MODE_CTR,
                                        init_vect=init_vect)

buffer_size = 128

plain_file = open(plain_file_path, 'rb')
cipher_file = open(cipher_file_path, 'wb')
buffer = plain_file.read(buffer_size)
while len(buffer) > 0:
    cipher_data = cipher_obj.encrypt(buffer)
    cipher_file.write(cipher_data)
    buffer = plain_file.read(buffer_size))

Calculating MAC of the file

In this case the ‘buffer_size’ value must be a multiple of the ‘block_size’ value.

import gostcrypto

key = bytearray([
    0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
    0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
])

plain_file_path = 'plain_file.txt'
cipher_obj = gostcrypto.gostcipher.new('kuznechik',
                                        key,
                                        gostcrypto.gostcipher.MODE_MAC)

buffer_size = 128

plain_file = open(plain_file_path, 'rb')
buffer = plain_file.read(buffer_size)
while len(buffer) > 0:
    cipher_obj.update(buffer)
    buffer = plain_file.read(buffer_size)
mac_result = cipher_obj.digest(8)

Usage gostsignature module

Signing

import gostcrypto

private_key = bytearray.fromhex('7a929ade789bb9be10ed359dd39a72c11b60961f49397eee1d19ce9891ec3b28')
digest = bytearray.fromhex('2dfbc1b372d89a1188c09c52e0eec61fce52032ab1022e8e67ece6672b043ee5')

sign_obj = gostcrypto.gostsignature.new(gostcrypto.gostsignature.MODE_256,
                                        gostcrypto.gostsignature.CURVES_R_1323565_1_024_2019['id-tc26-gost-3410-2012-256-paramSetB'])

signature = sign_obj.sign(private_key, digest)

Verify

public_key = bytearray.fromhex('fd21c21ab0dc84c154f3d218e9040bee64fff48bdff814b232295b09d0df72e45026dec9ac4f07061a2a01d7a2307e0659239a82a95862df86041d1458e45049')
digest = bytearray.fromhex('2dfbc1b372d89a1188c09c52e0eec61fce52032ab1022e8e67ece6672b043ee5')
signature = bytearray.fromhex('4b6dd64fa33820e90b14f8f4e49ee92eb2660f9eeb4e1b313517b6ba173979656df13cd4bceaf606ed32d410f48f2a5c2596c146e8c2fa4455d08cf68fc2b2a7')

sign_obj = gostcrypto.gostsignature.new(gostcrypto.gostsignature.MODE_256,
                                        gostcrypto.gostsignature.CURVES_R_1323565_1_024_2019['id-tc26-gost-3410-2012-256-paramSetB'])

if sign_obj.verify(public_key, digest, signature):
    print('Signature is correct')
else:
    print('Signature is not correct')

Generating a public key

private_key = bytearray.fromhex('7a929ade789bb9be10ed359dd39a72c11b60961f49397eee1d19ce9891ec3b28')

sign_obj = gostcrypto.gostsignature.new(gostcrypto.gostsignature.MODE_256,
                                        gostcrypto.gostsignature.CURVES_R_1323565_1_024_2019['id-tc26-gost-3410-2012-256-paramSetB'])

public_key = sign_obj.public_key_generate(private_key)

Getting the identifier of the signature mode object name

import gostcrypto

sign_obj = gostcrypto.gostsignature.new(gostcrypto.gostsignature.MODE_256,
    gostcrypto.gostsignature.CURVES_R_1323565_1_024_2019['id-tc26-gost-3410-2012-256-paramSetB'])
oid_name = sign_obj.oid.name

Usage gostrandom module

import gostcrypto

rand_k = bytearray([
    0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff,
    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
    0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10,
    0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
])

random_obj = gostcrypto.gostrandom.new(32,
                                   rand_k=rand_k,
                                   size_s=gostcrypto.gostrandom.SIZE_S_256)
random_result = random_obj.random()
random_obj.clear()

Usage gosthmac module

Getting a HMAC for a string

import gostcrypto

key = bytearray.fromhex('000102030405060708090a0b0c0d0e0f1011121315161718191a1b1c1d1e1f')
data = bytearray.fromhex('0126bdb87800af214341456563780100')

hmac_obj = gostcrypto.gosthmac.new('HMAC_GOSTR3411_2012_256', key, data=data)
hmac_result = hmac_obj.digest()

Getting a HMAC for a file

In this case the ‘buffer_size’ value must be a multiple of the ‘block_size’ value.

import gostcrypto

key = bytearray.fromhex('000102030405060708090a0b0c0d0e0f1011121315161718191a1b1c1d1e1f')
data = bytearray.fromhex('0126bdb87800af214341456563780100')

hmac_obj = gostcrypto.gosthmac.new('HMAC_GOSTR3411_2012_256', key, data=data)
hmac_result = hmac_obj.digest()

Getting the name identifier of the HMAC algorithm object

import gostcrypto

key = bytearray.fromhex('000102030405060708090a0b0c0d0e0f1011121315161718191a1b1c1d1e1f')
hmac_obj = gostcrypto.gosthmac.new('HMAC_GOSTR3411_2012_256', key)
oid_name = hmac_obj.oid.name

Usage gostpbkdf module

import gostcrypto

password = b'password'
salt = b'salt'

pbkdf_obj = gostcrypto.gostpbkdf.new(password, salt=salt, counter=4096)
pbkdf_result = pbkdf_obj.derive(32)

License

MIT Copyright (c) 2020 Evgeny Drobotun

Documentation

Documentation for using this package: https://gostcrypto.readthedocs.io/

Release History

1.2.4 (17.09.2020)

• Fixed a default initial vector bug (added default initial vector for ‘magma’ algorithm)

1.2.3 (23.05.2020)

• Added Python version checking (use version 3.6 or higher)

1.2.2 (15.05.2020)

• Fixed a MAC calculation bug when using padding in the gostcipher module (in earlier versions (including 1.2.1), the MAC with padding was calculated incorrectly (the bug was in the ‘msb’ and ‘update’ functions))

1.2.1 (13.05.2020)

• Fixed a MAC calculation bug when using padding in the gostcipher module

1.2.0 (07.05.2020)

• Refactoring and code modification in module gostcipher to increase the performance of encryption algorithm ‘kuznechik’ (uses precomputation values of the ‘gf’ function; the performance of the encryption function has increased by an average of 5..10 times)

• Refactoring and code modification in module gosthash to increase the performance of hasing (uses precomputation values of the ‘l, s and p-transformation’, function; the performance of the encryption function has increased by an average of 2..7 times)

• Added the gostoid module that implements generating cryptographic object IDs for the gostcipher, gosthash, gosthmac and gostsignature modules

1.1.2 (02.05.2020)

• Refactoring gostcipher module (changed the class hierarchy to remove code duplication)

• Refactoring gosthash module (remove code duplication)

• Fixed some minor bugs

• Updated docstring in accordance with the Google Python Style Guide

1.1.1 (20.04.2020)

• Use **kvargs in the new function with default parameters (gostrandom, gosthash, gosthmac, gostpbkdf)

• Add the ability to pass data to the new function from gosthmac

• Fixed some minor bugs in the gostrandom module

1.1.0 (15.04.2020)

• Refactoring code gostcipher module (changed the class structure)

• Each module has its own exception class added

• In the new function of the gostcipher module for MAC mode, it is now possible to pass data for MAC calculation, followed by calling the digest method without first calling the update method

• In the new function of the gosthash module, it is now possible to pass data for hash calculation, followed by calling the digest method without first calling the update method

• Added new exceptions for various conflict situations

• Fixed some minor bugs

1.0.0 (08.04.2020)

• First release of ‘gostcrypto’