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#!/usr/bin/env python3
"""
Use PyCrypto to generate test data for Cryptech ModExp core.
"""
# Author: Rob Austein
# Copyright (c) 2015, NORDUnet A/S
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
# - Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# - Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# - Neither the name of the NORDUnet nor the names of its contributors may
# be used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
# TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
from argparse import ArgumentParser, FileType
from binascii import hexlify
from Crypto import __version__ as PyCryptoVersion
from Crypto.PublicKey import RSA
from Crypto.Hash import SHA256
from Crypto.Util.number import long_to_bytes, inverse
from Crypto.Signature.PKCS1_v1_5 import EMSA_PKCS1_V1_5_ENCODE, PKCS115_SigScheme
from textwrap import TextWrapper
import sys, os.path
def KeyLengthType(arg):
val = int(arg)
if val % 8 != 0:
raise ValueError
return val
parser = ArgumentParser(description = __doc__)
parser.add_argument("--pad-to-modulus", action = "store_true",
help = "zero-pad to modulus size (bug workaround)")
parser.add_argument("--extra-word", action = "store_true",
help = "add extra word of zero padding (bug workaround)")
parser.add_argument("-k", "--key-lengths", type = KeyLengthType,
nargs = "*", default = [1024, 2048, 4096],
help = "Lengths in bits of keys to generate")
parser.add_argument("--pkcs-encoding", type = int, choices = (1, 8), default = 8,
help = "PKCS encoding to use for PEM commented private key")
parser.add_argument("output", nargs = "?", type = FileType("w"), default = sys.stdout,
help = "output file")
args = parser.parse_args()
plaintext = "You can hack anything you want with TECO and DDT."
scriptname = os.path.basename(sys.argv[0])
wrapper = TextWrapper(width = 78, initial_indent = " " * 2, subsequent_indent = " " * 2)
def printlines(*lines, **kwargs):
for line in lines:
args.output.write(line.format(**kwargs) + "\n")
def trailing_comma(item, sequence):
return "" if item == sequence[-1] else ","
def print_hex(name, value, comment):
value = hexlify(value).decode("ascii")
printlines("static const uint8_t {name}[] = {{ /* {comment}, {length:d} bytes */",
wrapper.fill(", ".join("0x" + value[i : i + 2] for i in range(0, len(value), 2)))
"}};", "",
name = name, comment = comment, length = len(value))
def pad_to_blocksize(value, blocksize):
extra = len(value) % blocksize
return value if extra == 0 else (b"\x00" * (blocksize - extra)) + value
# Funnily enough, PyCrypto and Cryptlib use exactly the same names for
# RSA key components, see Cryptlib documentation pages 186-187 & 339.
h = SHA256.new(plaintext.encode("ascii"))
printlines("/*",
" * RSA signature test data for Cryptech project, automatically generated by",
" * {scriptname} using PyCrypto version {version}. Do not edit.",
" *",
" * Plaintext: \"{plaintext}\"",
" * SHA-256: {digest}",
" */", "",
scriptname = scriptname,
version = PyCryptoVersion,
plaintext = plaintext,
digest = h.hexdigest())
fields = ("n", "e", "d", "p", "q", "dP", "dQ", "u", "m", "s")
for k_len in args.key_lengths:
k = RSA.generate(k_len) # Cryptlib insists u < p, probably with good reason,
while k.u >= k.p: # and I'm sure not going to argue the math with Peter,
k = RSA.generate(k_len) # so keep trying until we pass this test
m = EMSA_PKCS1_V1_5_ENCODE(h, k_len/8)
s = PKCS115_SigScheme(k).sign(h)
assert len(m) == len(s)
if args.pad_to_modulus:
blocksize = k_len/8
if args.extra_word:
blocksize += 4
else:
blocksize = 4
printlines("/* {k_len:d}-bit RSA private key (PKCS #{pkcs:d})",
k.exportKey(format = "PEM", pkcs = args.pkcs_encoding),
"*/", "",
k_len = k_len, pkcs = args.pkcs_encoding)
# PyCrypto doesn't precalculate dP or dQ, and for some reason it
# does u backwards (uses (1/p % q) and swaps the roles of p and q in
# the CRT calculation to compensate), so we just calculate our own.
for name in fields:
if name in "ms":
continue
elif name == "dP":
value = k.d % (k.p - 1)
elif name == "dQ":
value = k.d % (k.q - 1)
elif name == "u":
value = inverse(k.q, k.p)
else:
value = getattr(k, name)
print_hex("{}_{:d}".format(name, k_len),
long_to_bytes(value, blocksize = blocksize),
"key component {}".format(name))
print_hex("m_{:d}".format(k_len), pad_to_blocksize(m, blocksize), "message to be signed")
print_hex("s_{:d}".format(k_len), pad_to_blocksize(s, blocksize), "signed message")
printlines("typedef struct {{ const uint8_t *val; size_t len; }} rsa_tc_bn_t;",
"typedef struct {{ size_t size; rsa_tc_bn_t {fields}; }} rsa_tc_t;",
"",
"static const rsa_tc_t rsa_tc[] = {{",
fields = ", ".join(fields))
for k_len in args.key_lengths:
printlines(" {{ {k_len:d},", k_len = k_len)
for field in fields:
printlines(" {{ {field}_{k_len:d}, sizeof({field}_{k_len:d}) }}{comma}",
field = field, k_len = k_len, comma = trailing_comma(field, fields))
printlines(" }}{comma}", comma = trailing_comma(k_len, args.key_lengths))
printlines("}};")
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