From d454bde3c361b6e2474e6c15397c26049f83f7d5 Mon Sep 17 00:00:00 2001 From: PlexSheep Date: Sat, 3 Jun 2023 18:24:25 +0200 Subject: [PATCH] rsa padding done --- src-py/plexcryptool/scripts/authur1.py | 2 +- src-py/plexcryptool/scripts/basic-decrypt.py | 2 +- src-py/plexcryptool/scripts/common.py | 17 +++ src-py/plexcryptool/scripts/md5-analyzer.py | 3 +- .../plexcryptool/scripts/oaep-ciphertext.txt | 1 - src-py/plexcryptool/scripts/oaep_rsa.py | 2 +- src-py/plexcryptool/scripts/rsa_padding.py | 104 ++++++++++++++++++ src-py/plexcryptool/scripts/trash-hash.py | 2 +- 8 files changed, 126 insertions(+), 7 deletions(-) delete mode 100644 src-py/plexcryptool/scripts/oaep-ciphertext.txt create mode 100644 src-py/plexcryptool/scripts/rsa_padding.py diff --git a/src-py/plexcryptool/scripts/authur1.py b/src-py/plexcryptool/scripts/authur1.py index 875e7e4..16de2de 100755 --- a/src-py/plexcryptool/scripts/authur1.py +++ b/src-py/plexcryptool/scripts/authur1.py @@ -6,7 +6,7 @@ Since this (auth) hash did not have a name before, I gave it the name 'authur1' @author: Christoph J. Scherr @license: MIT -@source: https://git.cscherr.de/PlexSheep/plexcryptool/src/branch/master/plexcryptool/authur1.py +@source: https://git.cscherr.de/PlexSheep/plexcryptool/ """ import argparse import random diff --git a/src-py/plexcryptool/scripts/basic-decrypt.py b/src-py/plexcryptool/scripts/basic-decrypt.py index 30c980d..c76c4f4 100755 --- a/src-py/plexcryptool/scripts/basic-decrypt.py +++ b/src-py/plexcryptool/scripts/basic-decrypt.py @@ -5,7 +5,7 @@ you also need the chiffrat.txt file in the same directory. @license: MIT @author: Christoph J. Scherr -@source: https://git.cscherr.de/PlexSheep/plexcryptool/src/branch/master/plexcryptool/basic-decrypt.py +@source: https://git.cscherr.de/PlexSheep/plexcryptool/ """ MAX_IN_LINE = 16 DE_MOST_COMMON = ['E', 'N', 'I', 'R', 'A'] diff --git a/src-py/plexcryptool/scripts/common.py b/src-py/plexcryptool/scripts/common.py index 1c7a8ae..a9e25af 100644 --- a/src-py/plexcryptool/scripts/common.py +++ b/src-py/plexcryptool/scripts/common.py @@ -7,6 +7,7 @@ Common tools that may be used by many """ from math import floor +from typing import Literal def byte_xor(ba0: bytearray, ba1: bytearray) -> bytearray: """ @@ -27,3 +28,19 @@ def calc_byte_len(n: int) -> int: return 1 + floor(len) else: return floor(len) + +def int_to_bytearray(n: int, size: int|None = None, endianness = 'big') -> bytearray: + """ + convert an integer to a bytearray + + you can specify a size if you want, if the number is too big an Exception will be raised. + size is in bytes + """ + brepr: bytes = n.to_bytes(calc_byte_len(n), endianness) + ba: bytearray = bytearray(brepr) + if size is not None and len(ba) > size: + raise Exception("Number is larger than requested") + while size is not None and size > len(ba): + ba: bytearray = bytearray(1) + ba + + return ba diff --git a/src-py/plexcryptool/scripts/md5-analyzer.py b/src-py/plexcryptool/scripts/md5-analyzer.py index f56f342..1638048 100755 --- a/src-py/plexcryptool/scripts/md5-analyzer.py +++ b/src-py/plexcryptool/scripts/md5-analyzer.py @@ -4,8 +4,7 @@ A small script to help analyze the md5 hash function. @author: Christoph J. Scherr @license: MIT -@source: https://git.cscherr.de/PlexSheep/plexcryptool/src/branch/master/plexcryptool/md5-analyzer.py -TODO do I need to implement md5 by myself for the assignment? +@source: https://git.cscherr.de/PlexSheep/plexcryptool/ """ import argparse import hashlib diff --git a/src-py/plexcryptool/scripts/oaep-ciphertext.txt b/src-py/plexcryptool/scripts/oaep-ciphertext.txt deleted file mode 100644 index b147ec6..0000000 --- a/src-py/plexcryptool/scripts/oaep-ciphertext.txt +++ /dev/null @@ -1 +0,0 @@ -0976f89569d94414fed4f7714cd85c840dbf338781926f5d1f6284688c97eaeef7f42b3d844c70468cfb960092235855da5d5c66107dfee4204c1a78512ee00306da957a856a085affe40b2ab32fc90a8c8e059feea9a83e753618aeae04884aa1658afe59a69c30ec5c014a5da06ff484143ca1ea884b44a3f92d063db8503f diff --git a/src-py/plexcryptool/scripts/oaep_rsa.py b/src-py/plexcryptool/scripts/oaep_rsa.py index af8fe46..a0f42db 100755 --- a/src-py/plexcryptool/scripts/oaep_rsa.py +++ b/src-py/plexcryptool/scripts/oaep_rsa.py @@ -4,7 +4,7 @@ Perform RSA-OAEP @author: Christoph J. Scherr @license: MIT -@source: https://git.cscherr.de/PlexSheep/plexcryptool/src/branch/master/plexcryptool/trash-hash.py +@source: https://git.cscherr.de/PlexSheep/plexcryptool/ """ import argparse diff --git a/src-py/plexcryptool/scripts/rsa_padding.py b/src-py/plexcryptool/scripts/rsa_padding.py new file mode 100644 index 0000000..0eb6570 --- /dev/null +++ b/src-py/plexcryptool/scripts/rsa_padding.py @@ -0,0 +1,104 @@ +""" +Rsa padding script for croptology lectures + +@author: Christoph J. Scherr +@license: MIT +@source: https://git.cscherr.de/PlexSheep/plexcryptool/ +""" + +import argparse + +import plexcryptool +import common + +# predefined constants +P = 2**206 - 5 +Q = 2**226 -5 +N = P*Q +D = 0xaffe0815 +CIPHERTEXTS: list[int] = [ + 0x78766a52455329b486aaa414c3a029834a7e4b6ed87019dce4056f4d8999b137404d9ec4df28da201c9b0bc142deb1d86ff94d83becc, + 0x670b865216dfd0aacd5f7fa8802e704fa82f3fb9c7dbe3eb5a9ec308a1a2288648b15d5cc8ba2f54b245a972aea977932c9c84cf6422, + 0x61d5f2a4298bff3d6ebcd78830fb9181d97235623819eb7c60b92dcdf836a6cf731c60187e72f471c05d1c6eab216c3f6032af3c5370, + 0x3651009d02a0c72b9bc206c57d12277594d9eaad28bb3de5d661670b42f1cfafe688b9674e34d4ad79db898205417086e7e1877b9ef1, + 0x96e51d4675c6be5b14ec0cf2a9e9a9610a99d632723b3f1fcfc6b36806f5d74045f47622817cc35f6ffe9afe29f0aa236cbe12371651, + ] + +def padding_check(cihpertext: int, private_key: tuple[int, int], verbose: bool = False) -> bool: + """ + Check the padding of a given cihpertext + """ + decrypted: int = pow(cihpertext, private_key[0], private_key[1]) + # the ciphertexts seem to all be 54B long, so I have just hardcoded that + cleartext: bytearray = common.int_to_bytearray(decrypted, 54) + if verbose: + print(f"original:\t{cihpertext:054x}") + print(f"decrypted:\t{cleartext.hex()}") + + index: int = 0 + padding_active: bool = False + for b in cleartext: + + if index == 0 and b != 0: + # the first byte has to be 0x00 + if verbose: + print(f"error:\t\tThe first byte is not 00: {b:02x}") + return False + elif index == 1: + # the second byte is the padding type, we only accept 01 and 02 type padding + if b == 1: + padding_active = True + pad_type = b + if verbose: + print(f"type:\t\t01 deterministic padding") + elif b == 2: + padding_active = True + pad_type = b + if verbose: + print(f"type:\t\t02 nondeterministic padding") + else: + if verbose: + print(f"error:\t\tThe second byte is not 01 or 02 (block type): {b:02x}") + return False + elif padding_active: + if b == 0: + # padding has ended + padding_active = False + continue + if pad_type == 1 and b != 0xff: + if verbose: + print(f"error:\t\tPadding of type 01 contains non ff byte: {b:02x}") + return False + elif pad_type == 2: + if b == 0: + # must be random non 00 + if verbose: + print(f"error:\t\tPadding of type 02 contains 00 byte: {b:02x}") + return False + + + + index += 1 + + if padding_active: + if verbose: + print(f"error:\t\tPadding has not been ended with 00 byte") + + + return True + +def main(): + parser = argparse.ArgumentParser(prog="rsa-padding", description='validates a rsa padding') + parser.add_argument('-v', '--verbose', action="store_true", + help='append some auth hashed stuff') + args = parser.parse_args() + + results: list[bool] = [] + for c in CIPHERTEXTS: + b = padding_check(c, (D, N), args.verbose) + print(f"Passed:\t\t{b}") + plexcryptool.cplex.printing.seperator() + + +if __name__ == "__main__": + main() diff --git a/src-py/plexcryptool/scripts/trash-hash.py b/src-py/plexcryptool/scripts/trash-hash.py index c60d545..99d8edc 100755 --- a/src-py/plexcryptool/scripts/trash-hash.py +++ b/src-py/plexcryptool/scripts/trash-hash.py @@ -4,7 +4,7 @@ Dirty hash we covered in an excercise for Week 16 of 2023 in cryptography @author: Christoph J. Scherr @license: MIT -@source: https://git.cscherr.de/PlexSheep/plexcryptool/src/branch/master/plexcryptool/trash-hash.py +@source: https://git.cscherr.de/PlexSheep/plexcryptool/ """ import math import argparse