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📄 __init__.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """RSA module Module for calculating large primes, and RSA encryption, decryption, signing and verification. Includes generating public and private keys. WARNING: this implementation does not use compression of the cleartext input to prevent repetitions, or other common security improvements. Use with care. """ from rsa.key import newkeys, PrivateKey, PublicKey from rsa.pkcs1 import encrypt, decrypt, sign, verify, DecryptionError, \ VerificationError, find_signature_hash, sign_hash, compute_hash __author__ = "Sybren Stuvel, Barry Mead and Yesudeep Mangalapilly" __date__ = "2020-06-12" __version__ = '4.5' # Do doctest if we're run directly if __name__ == "__main__": import doctest doctest.testmod() __all__ = ["newkeys", "encrypt", "decrypt", "sign", "verify", 'PublicKey', 'PrivateKey', 'DecryptionError', 'VerificationError', 'compute_hash', 'sign_hash']	1.51 KB	2021-04-05 15:08
📄 _compat.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Python compatibility wrappers.""" from __future__ import absolute_import import itertools import sys from struct import pack MAX_INT = sys.maxsize MAX_INT64 = (1 << 63) - 1 MAX_INT32 = (1 << 31) - 1 MAX_INT16 = (1 << 15) - 1 PY2 = sys.version_info[0] == 2 # Determine the word size of the processor. if MAX_INT == MAX_INT64: # 64-bit processor. MACHINE_WORD_SIZE = 64 elif MAX_INT == MAX_INT32: # 32-bit processor. MACHINE_WORD_SIZE = 32 else: # Else we just assume 64-bit processor keeping up with modern times. MACHINE_WORD_SIZE = 64 if PY2: integer_types = (int, long) range = xrange zip = itertools.izip else: integer_types = (int, ) range = range zip = zip def write_to_stdout(data): """Writes bytes to stdout :type data: bytes """ if PY2: sys.stdout.write(data) else: # On Py3 we must use the buffer interface to write bytes. sys.stdout.buffer.write(data) def is_bytes(obj): """ Determines whether the given value is a byte string. :param obj: The value to test. :returns: ``True`` if ``value`` is a byte string; ``False`` otherwise. """ return isinstance(obj, bytes) def is_integer(obj): """ Determines whether the given value is an integer. :param obj: The value to test. :returns: ``True`` if ``value`` is an integer; ``False`` otherwise. """ return isinstance(obj, integer_types) def byte(num): """ Converts a number between 0 and 255 (both inclusive) to a base-256 (byte) representation. Use it as a replacement for ``chr`` where you are expecting a byte because this will work on all current versions of Python:: :param num: An unsigned integer between 0 and 255 (both inclusive). :returns: A single byte. """ return pack("B", num) def xor_bytes(b1, b2): """ Returns the bitwise XOR result between two bytes objects, b1 ^ b2. Bitwise XOR operation is commutative, so order of parameters doesn't generate different results. If parameters have different length, extra length of the largest one is ignored. :param b1: First bytes object. :param b2: Second bytes object. :returns: Bytes object, result of XOR operation. """ if PY2: return ''.join(byte(ord(x) ^ ord(y)) for x, y in zip(b1, b2)) return bytes(x ^ y for x, y in zip(b1, b2)) def get_word_alignment(num, force_arch=64, _machine_word_size=MACHINE_WORD_SIZE): """ Returns alignment details for the given number based on the platform Python is running on. :param num: Unsigned integral number. :param force_arch: If you don't want to use 64-bit unsigned chunks, set this to anything other than 64. 32-bit chunks will be preferred then. Default 64 will be used when on a 64-bit machine. :param _machine_word_size: (Internal) The machine word size used for alignment. :returns: 4-tuple:: (word_bits, word_bytes, max_uint, packing_format_type) """ max_uint64 = 0xffffffffffffffff max_uint32 = 0xffffffff max_uint16 = 0xffff max_uint8 = 0xff if force_arch == 64 and _machine_word_size >= 64 and num > max_uint32: # 64-bit unsigned integer. return 64, 8, max_uint64, "Q" elif num > max_uint16: # 32-bit unsigned integer return 32, 4, max_uint32, "L" elif num > max_uint8: # 16-bit unsigned integer. return 16, 2, max_uint16, "H" else: # 8-bit unsigned integer. return 8, 1, max_uint8, "B"	4.24 KB	2021-04-05 15:08
📄 asn1.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """ASN.1 definitions. Not all ASN.1-handling code use these definitions, but when it does, they should be here. """ from pyasn1.type import univ, namedtype, tag class PubKeyHeader(univ.Sequence): componentType = namedtype.NamedTypes( namedtype.NamedType('oid', univ.ObjectIdentifier()), namedtype.NamedType('parameters', univ.Null()), ) class OpenSSLPubKey(univ.Sequence): componentType = namedtype.NamedTypes( namedtype.NamedType('header', PubKeyHeader()), # This little hack (the implicit tag) allows us to get a Bit String as Octet String namedtype.NamedType('key', univ.OctetString().subtype( implicitTag=tag.Tag(tagClass=0, tagFormat=0, tagId=3))), ) class AsnPubKey(univ.Sequence): """ASN.1 contents of DER encoded public key: RSAPublicKey ::= SEQUENCE { modulus INTEGER, -- n publicExponent INTEGER, -- e """ componentType = namedtype.NamedTypes( namedtype.NamedType('modulus', univ.Integer()), namedtype.NamedType('publicExponent', univ.Integer()), )	1.74 KB	2021-04-05 15:08
📄 cli.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Commandline scripts. These scripts are called by the executables defined in setup.py. """ from __future__ import with_statement, print_function import abc import sys from optparse import OptionParser import rsa import rsa.pkcs1 HASH_METHODS = sorted(rsa.pkcs1.HASH_METHODS.keys()) def keygen(): """Key generator.""" # Parse the CLI options parser = OptionParser(usage='usage: %prog [options] keysize', description='Generates a new RSA keypair of "keysize" bits.') parser.add_option('--pubout', type='string', help='Output filename for the public key. The public key is ' 'not saved if this option is not present. You can use ' 'pyrsa-priv2pub to create the public key file later.') parser.add_option('-o', '--out', type='string', help='Output filename for the private key. The key is ' 'written to stdout if this option is not present.') parser.add_option('--form', help='key format of the private and public keys - default PEM', choices=('PEM', 'DER'), default='PEM') (cli, cli_args) = parser.parse_args(sys.argv[1:]) if len(cli_args) != 1: parser.print_help() raise SystemExit(1) try: keysize = int(cli_args[0]) except ValueError: parser.print_help() print('Not a valid number: %s' % cli_args[0], file=sys.stderr) raise SystemExit(1) print('Generating %i-bit key' % keysize, file=sys.stderr) (pub_key, priv_key) = rsa.newkeys(keysize) # Save public key if cli.pubout: print('Writing public key to %s' % cli.pubout, file=sys.stderr) data = pub_key.save_pkcs1(format=cli.form) with open(cli.pubout, 'wb') as outfile: outfile.write(data) # Save private key data = priv_key.save_pkcs1(format=cli.form) if cli.out: print('Writing private key to %s' % cli.out, file=sys.stderr) with open(cli.out, 'wb') as outfile: outfile.write(data) else: print('Writing private key to stdout', file=sys.stderr) rsa._compat.write_to_stdout(data) class CryptoOperation(object): """CLI callable that operates with input, output, and a key.""" __metaclass__ = abc.ABCMeta keyname = 'public' # or 'private' usage = 'usage: %%prog [options] %(keyname)s_key' description = None operation = 'decrypt' operation_past = 'decrypted' operation_progressive = 'decrypting' input_help = 'Name of the file to %(operation)s. Reads from stdin if ' \ 'not specified.' output_help = 'Name of the file to write the %(operation_past)s file ' \ 'to. Written to stdout if this option is not present.' expected_cli_args = 1 has_output = True key_class = rsa.PublicKey def __init__(self): self.usage = self.usage % self.__class__.__dict__ self.input_help = self.input_help % self.__class__.__dict__ self.output_help = self.output_help % self.__class__.__dict__ @abc.abstractmethod def perform_operation(self, indata, key, cli_args): """Performs the program's operation. Implement in a subclass. :returns: the data to write to the output. """ def __call__(self): """Runs the program.""" (cli, cli_args) = self.parse_cli() key = self.read_key(cli_args[0], cli.keyform) indata = self.read_infile(cli.input) print(self.operation_progressive.title(), file=sys.stderr) outdata = self.perform_operation(indata, key, cli_args) if self.has_output: self.write_outfile(outdata, cli.output) def parse_cli(self): """Parse the CLI options :returns: (cli_opts, cli_args) """ parser = OptionParser(usage=self.usage, description=self.description) parser.add_option('-i', '--input', type='string', help=self.input_help) if self.has_output: parser.add_option('-o', '--output', type='string', help=self.output_help) parser.add_option('--keyform', help='Key format of the %s key - default PEM' % self.keyname, choices=('PEM', 'DER'), default='PEM') (cli, cli_args) = parser.parse_args(sys.argv[1:]) if len(cli_args) != self.expected_cli_args: parser.print_help() raise SystemExit(1) return cli, cli_args def read_key(self, filename, keyform): """Reads a public or private key.""" print('Reading %s key from %s' % (self.keyname, filename), file=sys.stderr) with open(filename, 'rb') as keyfile: keydata = keyfile.read() return self.key_class.load_pkcs1(keydata, keyform) def read_infile(self, inname): """Read the input file""" if inname: print('Reading input from %s' % inname, file=sys.stderr) with open(inname, 'rb') as infile: return infile.read() print('Reading input from stdin', file=sys.stderr) return sys.stdin.read() def write_outfile(self, outdata, outname): """Write the output file""" if outname: print('Writing output to %s' % outname, file=sys.stderr) with open(outname, 'wb') as outfile: outfile.write(outdata) else: print('Writing output to stdout', file=sys.stderr) rsa._compat.write_to_stdout(outdata) class EncryptOperation(CryptoOperation): """Encrypts a file.""" keyname = 'public' description = ('Encrypts a file. The file must be shorter than the key ' 'length in order to be encrypted.') operation = 'encrypt' operation_past = 'encrypted' operation_progressive = 'encrypting' def perform_operation(self, indata, pub_key, cli_args=None): """Encrypts files.""" return rsa.encrypt(indata, pub_key) class DecryptOperation(CryptoOperation): """Decrypts a file.""" keyname = 'private' description = ('Decrypts a file. The original file must be shorter than ' 'the key length in order to have been encrypted.') operation = 'decrypt' operation_past = 'decrypted' operation_progressive = 'decrypting' key_class = rsa.PrivateKey def perform_operation(self, indata, priv_key, cli_args=None): """Decrypts files.""" return rsa.decrypt(indata, priv_key) class SignOperation(CryptoOperation): """Signs a file.""" keyname = 'private' usage = 'usage: %%prog [options] private_key hash_method' description = ('Signs a file, outputs the signature. Choose the hash ' 'method from %s' % ', '.join(HASH_METHODS)) operation = 'sign' operation_past = 'signature' operation_progressive = 'Signing' key_class = rsa.PrivateKey expected_cli_args = 2 output_help = ('Name of the file to write the signature to. Written ' 'to stdout if this option is not present.') def perform_operation(self, indata, priv_key, cli_args): """Signs files.""" hash_method = cli_args[1] if hash_method not in HASH_METHODS: raise SystemExit('Invalid hash method, choose one of %s' % ', '.join(HASH_METHODS)) return rsa.sign(indata, priv_key, hash_method) class VerifyOperation(CryptoOperation): """Verify a signature.""" keyname = 'public' usage = 'usage: %%prog [options] public_key signature_file' description = ('Verifies a signature, exits with status 0 upon success, ' 'prints an error message and exits with status 1 upon error.') operation = 'verify' operation_past = 'verified' operation_progressive = 'Verifying' key_class = rsa.PublicKey expected_cli_args = 2 has_output = False def perform_operation(self, indata, pub_key, cli_args): """Verifies files.""" signature_file = cli_args[1] with open(signature_file, 'rb') as sigfile: signature = sigfile.read() try: rsa.verify(indata, signature, pub_key) except rsa.VerificationError: raise SystemExit('Verification failed.') print('Verification OK', file=sys.stderr) encrypt = EncryptOperation() decrypt = DecryptOperation() sign = SignOperation() verify = VerifyOperation()	8.99 KB	2021-04-05 15:08
📄 common.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. from rsa._compat import zip """Common functionality shared by several modules.""" class NotRelativePrimeError(ValueError): def __init__(self, a, b, d, msg=None): super(NotRelativePrimeError, self).__init__( msg or "%d and %d are not relatively prime, divider=%i" % (a, b, d)) self.a = a self.b = b self.d = d def bit_size(num): """ Number of bits needed to represent a integer excluding any prefix 0 bits. Usage:: >>> bit_size(1023) 10 >>> bit_size(1024) 11 >>> bit_size(1025) 11 :param num: Integer value. If num is 0, returns 0. Only the absolute value of the number is considered. Therefore, signed integers will be abs(num) before the number's bit length is determined. :returns: Returns the number of bits in the integer. """ try: return num.bit_length() except AttributeError: raise TypeError('bit_size(num) only supports integers, not %r' % type(num)) def byte_size(number): """ Returns the number of bytes required to hold a specific long number. The number of bytes is rounded up. Usage:: >>> byte_size(1 << 1023) 128 >>> byte_size((1 << 1024) - 1) 128 >>> byte_size(1 << 1024) 129 :param number: An unsigned integer :returns: The number of bytes required to hold a specific long number. """ if number == 0: return 1 return ceil_div(bit_size(number), 8) def ceil_div(num, div): """ Returns the ceiling function of a division between `num` and `div`. Usage:: >>> ceil_div(100, 7) 15 >>> ceil_div(100, 10) 10 >>> ceil_div(1, 4) 1 :param num: Division's numerator, a number :param div: Division's divisor, a number :return: Rounded up result of the division between the parameters. """ quanta, mod = divmod(num, div) if mod: quanta += 1 return quanta def extended_gcd(a, b): """Returns a tuple (r, i, j) such that r = gcd(a, b) = ia + jb """ # r = gcd(a,b) i = multiplicitive inverse of a mod b # or j = multiplicitive inverse of b mod a # Neg return values for i or j are made positive mod b or a respectively # Iterateive Version is faster and uses much less stack space x = 0 y = 1 lx = 1 ly = 0 oa = a # Remember original a/b to remove ob = b # negative values from return results while b != 0: q = a // b (a, b) = (b, a % b) (x, lx) = ((lx - (q * x)), x) (y, ly) = ((ly - (q * y)), y) if lx < 0: lx += ob # If neg wrap modulo orignal b if ly < 0: ly += oa # If neg wrap modulo orignal a return a, lx, ly # Return only positive values def inverse(x, n): """Returns the inverse of x % n under multiplication, a.k.a x^-1 (mod n) >>> inverse(7, 4) 3 >>> (inverse(143, 4) * 143) % 4 1 """ (divider, inv, _) = extended_gcd(x, n) if divider != 1: raise NotRelativePrimeError(x, n, divider) return inv def crt(a_values, modulo_values): """Chinese Remainder Theorem. Calculates x such that x = a[i] (mod m[i]) for each i. :param a_values: the a-values of the above equation :param modulo_values: the m-values of the above equation :returns: x such that x = a[i] (mod m[i]) for each i >>> crt([2, 3], [3, 5]) 8 >>> crt([2, 3, 2], [3, 5, 7]) 23 >>> crt([2, 3, 0], [7, 11, 15]) 135 """ m = 1 x = 0 for modulo in modulo_values: m = modulo for (m_i, a_i) in zip(modulo_values, a_values): M_i = m // m_i inv = inverse(M_i, m_i) x = (x + a_i M_i * inv) % m return x if __name__ == '__main__': import doctest doctest.testmod()	4.46 KB	2021-04-05 15:08
📄 core.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Core mathematical operations. This is the actual core RSA implementation, which is only defined mathematically on integers. """ from rsa._compat import is_integer def assert_int(var, name): if is_integer(var): return raise TypeError('%s should be an integer, not %s' % (name, var.__class__)) def encrypt_int(message, ekey, n): """Encrypts a message using encryption key 'ekey', working modulo n""" assert_int(message, 'message') assert_int(ekey, 'ekey') assert_int(n, 'n') if message < 0: raise ValueError('Only non-negative numbers are supported') if message > n: raise OverflowError("The message %i is too long for n=%i" % (message, n)) return pow(message, ekey, n) def decrypt_int(cyphertext, dkey, n): """Decrypts a cypher text using the decryption key 'dkey', working modulo n""" assert_int(cyphertext, 'cyphertext') assert_int(dkey, 'dkey') assert_int(n, 'n') message = pow(cyphertext, dkey, n) return message	1.62 KB	2021-04-05 15:08
📄 key.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """RSA key generation code. Create new keys with the newkeys() function. It will give you a PublicKey and a PrivateKey object. Loading and saving keys requires the pyasn1 module. This module is imported as late as possible, such that other functionality will remain working in absence of pyasn1. .. note:: Storing public and private keys via the `pickle` module is possible. However, it is insecure to load a key from an untrusted source. The pickle module is not secure against erroneous or maliciously constructed data. Never unpickle data received from an untrusted or unauthenticated source. """ import logging import warnings from rsa._compat import range import rsa.prime import rsa.pem import rsa.common import rsa.randnum import rsa.core log = logging.getLogger(__name__) DEFAULT_EXPONENT = 65537 class AbstractKey(object): """Abstract superclass for private and public keys.""" __slots__ = ('n', 'e') def __init__(self, n, e): self.n = n self.e = e @classmethod def _load_pkcs1_pem(cls, keyfile): """Loads a key in PKCS#1 PEM format, implement in a subclass. :param keyfile: contents of a PEM-encoded file that contains the public key. :type keyfile: bytes :return: the loaded key :rtype: AbstractKey """ @classmethod def _load_pkcs1_der(cls, keyfile): """Loads a key in PKCS#1 PEM format, implement in a subclass. :param keyfile: contents of a DER-encoded file that contains the public key. :type keyfile: bytes :return: the loaded key :rtype: AbstractKey """ def _save_pkcs1_pem(self): """Saves the key in PKCS#1 PEM format, implement in a subclass. :returns: the PEM-encoded key. :rtype: bytes """ def _save_pkcs1_der(self): """Saves the key in PKCS#1 DER format, implement in a subclass. :returns: the DER-encoded key. :rtype: bytes """ @classmethod def load_pkcs1(cls, keyfile, format='PEM'): """Loads a key in PKCS#1 DER or PEM format. :param keyfile: contents of a DER- or PEM-encoded file that contains the key. :type keyfile: bytes :param format: the format of the file to load; 'PEM' or 'DER' :type format: str :return: the loaded key :rtype: AbstractKey """ methods = { 'PEM': cls._load_pkcs1_pem, 'DER': cls._load_pkcs1_der, } method = cls._assert_format_exists(format, methods) return method(keyfile) @staticmethod def _assert_format_exists(file_format, methods): """Checks whether the given file format exists in 'methods'. """ try: return methods[file_format] except KeyError: formats = ', '.join(sorted(methods.keys())) raise ValueError('Unsupported format: %r, try one of %s' % (file_format, formats)) def save_pkcs1(self, format='PEM'): """Saves the key in PKCS#1 DER or PEM format. :param format: the format to save; 'PEM' or 'DER' :type format: str :returns: the DER- or PEM-encoded key. :rtype: bytes """ methods = { 'PEM': self._save_pkcs1_pem, 'DER': self._save_pkcs1_der, } method = self._assert_format_exists(format, methods) return method() def blind(self, message, r): """Performs blinding on the message using random number 'r'. :param message: the message, as integer, to blind. :type message: int :param r: the random number to blind with. :type r: int :return: the blinded message. :rtype: int The blinding is such that message = unblind(decrypt(blind(encrypt(message))). See https://en.wikipedia.org/wiki/Blinding_%28cryptography%29 """ return (message * pow(r, self.e, self.n)) % self.n def unblind(self, blinded, r): """Performs blinding on the message using random number 'r'. :param blinded: the blinded message, as integer, to unblind. :param r: the random number to unblind with. :return: the original message. The blinding is such that message = unblind(decrypt(blind(encrypt(message))). See https://en.wikipedia.org/wiki/Blinding_%28cryptography%29 """ return (rsa.common.inverse(r, self.n) * blinded) % self.n class PublicKey(AbstractKey): """Represents a public RSA key. This key is also known as the 'encryption key'. It contains the 'n' and 'e' values. Supports attributes as well as dictionary-like access. Attribute access is faster, though. >>> PublicKey(5, 3) PublicKey(5, 3) >>> key = PublicKey(5, 3) >>> key.n 5 >>> key['n'] 5 >>> key.e 3 >>> key['e'] 3 """ __slots__ = ('n', 'e') def __getitem__(self, key): return getattr(self, key) def __repr__(self): return 'PublicKey(%i, %i)' % (self.n, self.e) def __getstate__(self): """Returns the key as tuple for pickling.""" return self.n, self.e def __setstate__(self, state): """Sets the key from tuple.""" self.n, self.e = state def __eq__(self, other): if other is None: return False if not isinstance(other, PublicKey): return False return self.n == other.n and self.e == other.e def __ne__(self, other): return not (self == other) def __hash__(self): return hash((self.n, self.e)) @classmethod def _load_pkcs1_der(cls, keyfile): """Loads a key in PKCS#1 DER format. :param keyfile: contents of a DER-encoded file that contains the public key. :return: a PublicKey object First let's construct a DER encoded key: >>> import base64 >>> b64der = 'MAwCBQCNGmYtAgMBAAE=' >>> der = base64.standard_b64decode(b64der) This loads the file: >>> PublicKey._load_pkcs1_der(der) PublicKey(2367317549, 65537) """ from pyasn1.codec.der import decoder from rsa.asn1 import AsnPubKey (priv, _) = decoder.decode(keyfile, asn1Spec=AsnPubKey()) return cls(n=int(priv['modulus']), e=int(priv['publicExponent'])) def _save_pkcs1_der(self): """Saves the public key in PKCS#1 DER format. :returns: the DER-encoded public key. :rtype: bytes """ from pyasn1.codec.der import encoder from rsa.asn1 import AsnPubKey # Create the ASN object asn_key = AsnPubKey() asn_key.setComponentByName('modulus', self.n) asn_key.setComponentByName('publicExponent', self.e) return encoder.encode(asn_key) @classmethod def _load_pkcs1_pem(cls, keyfile): """Loads a PKCS#1 PEM-encoded public key file. The contents of the file before the "-----BEGIN RSA PUBLIC KEY-----" and after the "-----END RSA PUBLIC KEY-----" lines is ignored. :param keyfile: contents of a PEM-encoded file that contains the public key. :return: a PublicKey object """ der = rsa.pem.load_pem(keyfile, 'RSA PUBLIC KEY') return cls._load_pkcs1_der(der) def _save_pkcs1_pem(self): """Saves a PKCS#1 PEM-encoded public key file. :return: contents of a PEM-encoded file that contains the public key. :rtype: bytes """ der = self._save_pkcs1_der() return rsa.pem.save_pem(der, 'RSA PUBLIC KEY') @classmethod def load_pkcs1_openssl_pem(cls, keyfile): """Loads a PKCS#1.5 PEM-encoded public key file from OpenSSL. These files can be recognised in that they start with BEGIN PUBLIC KEY rather than BEGIN RSA PUBLIC KEY. The contents of the file before the "-----BEGIN PUBLIC KEY-----" and after the "-----END PUBLIC KEY-----" lines is ignored. :param keyfile: contents of a PEM-encoded file that contains the public key, from OpenSSL. :type keyfile: bytes :return: a PublicKey object """ der = rsa.pem.load_pem(keyfile, 'PUBLIC KEY') return cls.load_pkcs1_openssl_der(der) @classmethod def load_pkcs1_openssl_der(cls, keyfile): """Loads a PKCS#1 DER-encoded public key file from OpenSSL. :param keyfile: contents of a DER-encoded file that contains the public key, from OpenSSL. :return: a PublicKey object :rtype: bytes """ from rsa.asn1 import OpenSSLPubKey from pyasn1.codec.der import decoder from pyasn1.type import univ (keyinfo, _) = decoder.decode(keyfile, asn1Spec=OpenSSLPubKey()) if keyinfo['header']['oid'] != univ.ObjectIdentifier('1.2.840.113549.1.1.1'): raise TypeError("This is not a DER-encoded OpenSSL-compatible public key") return cls._load_pkcs1_der(keyinfo['key'][1:]) class PrivateKey(AbstractKey): """Represents a private RSA key. This key is also known as the 'decryption key'. It contains the 'n', 'e', 'd', 'p', 'q' and other values. Supports attributes as well as dictionary-like access. Attribute access is faster, though. >>> PrivateKey(3247, 65537, 833, 191, 17) PrivateKey(3247, 65537, 833, 191, 17) exp1, exp2 and coef will be calculated: >>> pk = PrivateKey(3727264081, 65537, 3349121513, 65063, 57287) >>> pk.exp1 55063 >>> pk.exp2 10095 >>> pk.coef 50797 """ __slots__ = ('n', 'e', 'd', 'p', 'q', 'exp1', 'exp2', 'coef') def __init__(self, n, e, d, p, q): AbstractKey.__init__(self, n, e) self.d = d self.p = p self.q = q # Calculate exponents and coefficient. self.exp1 = int(d % (p - 1)) self.exp2 = int(d % (q - 1)) self.coef = rsa.common.inverse(q, p) def __getitem__(self, key): return getattr(self, key) def __repr__(self): return 'PrivateKey(%(n)i, %(e)i, %(d)i, %(p)i, %(q)i)' % self def __getstate__(self): """Returns the key as tuple for pickling.""" return self.n, self.e, self.d, self.p, self.q, self.exp1, self.exp2, self.coef def __setstate__(self, state): """Sets the key from tuple.""" self.n, self.e, self.d, self.p, self.q, self.exp1, self.exp2, self.coef = state def __eq__(self, other): if other is None: return False if not isinstance(other, PrivateKey): return False return (self.n == other.n and self.e == other.e and self.d == other.d and self.p == other.p and self.q == other.q and self.exp1 == other.exp1 and self.exp2 == other.exp2 and self.coef == other.coef) def __ne__(self, other): return not (self == other) def __hash__(self): return hash((self.n, self.e, self.d, self.p, self.q, self.exp1, self.exp2, self.coef)) def _get_blinding_factor(self): for _ in range(1000): blind_r = rsa.randnum.randint(self.n - 1) if rsa.prime.are_relatively_prime(self.n, blind_r): return blind_r raise RuntimeError('unable to find blinding factor') def blinded_decrypt(self, encrypted): """Decrypts the message using blinding to prevent side-channel attacks. :param encrypted: the encrypted message :type encrypted: int :returns: the decrypted message :rtype: int """ blind_r = self._get_blinding_factor() blinded = self.blind(encrypted, blind_r) # blind before decrypting decrypted = rsa.core.decrypt_int(blinded, self.d, self.n) return self.unblind(decrypted, blind_r) def blinded_encrypt(self, message): """Encrypts the message using blinding to prevent side-channel attacks. :param message: the message to encrypt :type message: int :returns: the encrypted message :rtype: int """ blind_r = self._get_blinding_factor() blinded = self.blind(message, blind_r) # blind before encrypting encrypted = rsa.core.encrypt_int(blinded, self.d, self.n) return self.unblind(encrypted, blind_r) @classmethod def _load_pkcs1_der(cls, keyfile): """Loads a key in PKCS#1 DER format. :param keyfile: contents of a DER-encoded file that contains the private key. :type keyfile: bytes :return: a PrivateKey object First let's construct a DER encoded key: >>> import base64 >>> b64der = 'MC4CAQACBQDeKYlRAgMBAAECBQDHn4npAgMA/icCAwDfxwIDANcXAgInbwIDAMZt' >>> der = base64.standard_b64decode(b64der) This loads the file: >>> PrivateKey._load_pkcs1_der(der) PrivateKey(3727264081, 65537, 3349121513, 65063, 57287) """ from pyasn1.codec.der import decoder (priv, _) = decoder.decode(keyfile) # ASN.1 contents of DER encoded private key: # # RSAPrivateKey ::= SEQUENCE { # version Version, # modulus INTEGER, -- n # publicExponent INTEGER, -- e # privateExponent INTEGER, -- d # prime1 INTEGER, -- p # prime2 INTEGER, -- q # exponent1 INTEGER, -- d mod (p-1) # exponent2 INTEGER, -- d mod (q-1) # coefficient INTEGER, -- (inverse of q) mod p # otherPrimeInfos OtherPrimeInfos OPTIONAL # } if priv[0] != 0: raise ValueError('Unable to read this file, version %s != 0' % priv[0]) as_ints = map(int, priv[1:6]) key = cls(as_ints) exp1, exp2, coef = map(int, priv[6:9]) if (key.exp1, key.exp2, key.coef) != (exp1, exp2, coef): warnings.warn( 'You have provided a malformed keyfile. Either the exponents ' 'or the coefficient are incorrect. Using the correct values ' 'instead.', UserWarning, ) return key def _save_pkcs1_der(self): """Saves the private key in PKCS#1 DER format. :returns: the DER-encoded private key. :rtype: bytes """ from pyasn1.type import univ, namedtype from pyasn1.codec.der import encoder class AsnPrivKey(univ.Sequence): componentType = namedtype.NamedTypes( namedtype.NamedType('version', univ.Integer()), namedtype.NamedType('modulus', univ.Integer()), namedtype.NamedType('publicExponent', univ.Integer()), namedtype.NamedType('privateExponent', univ.Integer()), namedtype.NamedType('prime1', univ.Integer()), namedtype.NamedType('prime2', univ.Integer()), namedtype.NamedType('exponent1', univ.Integer()), namedtype.NamedType('exponent2', univ.Integer()), namedtype.NamedType('coefficient', univ.Integer()), ) # Create the ASN object asn_key = AsnPrivKey() asn_key.setComponentByName('version', 0) asn_key.setComponentByName('modulus', self.n) asn_key.setComponentByName('publicExponent', self.e) asn_key.setComponentByName('privateExponent', self.d) asn_key.setComponentByName('prime1', self.p) asn_key.setComponentByName('prime2', self.q) asn_key.setComponentByName('exponent1', self.exp1) asn_key.setComponentByName('exponent2', self.exp2) asn_key.setComponentByName('coefficient', self.coef) return encoder.encode(asn_key) @classmethod def _load_pkcs1_pem(cls, keyfile): """Loads a PKCS#1 PEM-encoded private key file. The contents of the file before the "-----BEGIN RSA PRIVATE KEY-----" and after the "-----END RSA PRIVATE KEY-----" lines is ignored. :param keyfile: contents of a PEM-encoded file that contains the private key. :type keyfile: bytes :return: a PrivateKey object """ der = rsa.pem.load_pem(keyfile, b'RSA PRIVATE KEY') return cls._load_pkcs1_der(der) def _save_pkcs1_pem(self): """Saves a PKCS#1 PEM-encoded private key file. :return: contents of a PEM-encoded file that contains the private key. :rtype: bytes """ der = self._save_pkcs1_der() return rsa.pem.save_pem(der, b'RSA PRIVATE KEY') def find_p_q(nbits, getprime_func=rsa.prime.getprime, accurate=True): """Returns a tuple of two different primes of nbits bits each. The resulting p q has exacty 2 * nbits bits, and the returned p and q will not be equal. :param nbits: the number of bits in each of p and q. :param getprime_func: the getprime function, defaults to :py:func:`rsa.prime.getprime`. Introduced in Python-RSA 3.1 :param accurate: whether to enable accurate mode or not. :returns: (p, q), where p > q >>> (p, q) = find_p_q(128) >>> from rsa import common >>> common.bit_size(p * q) 256 When not in accurate mode, the number of bits can be slightly less >>> (p, q) = find_p_q(128, accurate=False) >>> from rsa import common >>> common.bit_size(p * q) <= 256 True >>> common.bit_size(p * q) > 240 True """ total_bits = nbits * 2 # Make sure that p and q aren't too close or the factoring programs can # factor n. shift = nbits // 16 pbits = nbits + shift qbits = nbits - shift # Choose the two initial primes log.debug('find_p_q(%i): Finding p', nbits) p = getprime_func(pbits) log.debug('find_p_q(%i): Finding q', nbits) q = getprime_func(qbits) def is_acceptable(p, q): """Returns True iff p and q are acceptable: - p and q differ - (p * q) has the right nr of bits (when accurate=True) """ if p == q: return False if not accurate: return True # Make sure we have just the right amount of bits found_size = rsa.common.bit_size(p * q) return total_bits == found_size # Keep choosing other primes until they match our requirements. change_p = False while not is_acceptable(p, q): # Change p on one iteration and q on the other if change_p: p = getprime_func(pbits) else: q = getprime_func(qbits) change_p = not change_p # We want p > q as described on # http://www.di-mgt.com.au/rsa_alg.html#crt return max(p, q), min(p, q) def calculate_keys_custom_exponent(p, q, exponent): """Calculates an encryption and a decryption key given p, q and an exponent, and returns them as a tuple (e, d) :param p: the first large prime :param q: the second large prime :param exponent: the exponent for the key; only change this if you know what you're doing, as the exponent influences how difficult your private key can be cracked. A very common choice for e is 65537. :type exponent: int """ phi_n = (p - 1) * (q - 1) try: d = rsa.common.inverse(exponent, phi_n) except rsa.common.NotRelativePrimeError as ex: raise rsa.common.NotRelativePrimeError( exponent, phi_n, ex.d, msg="e (%d) and phi_n (%d) are not relatively prime (divider=%i)" % (exponent, phi_n, ex.d)) if (exponent * d) % phi_n != 1: raise ValueError("e (%d) and d (%d) are not mult. inv. modulo " "phi_n (%d)" % (exponent, d, phi_n)) return exponent, d def calculate_keys(p, q): """Calculates an encryption and a decryption key given p and q, and returns them as a tuple (e, d) :param p: the first large prime :param q: the second large prime :return: tuple (e, d) with the encryption and decryption exponents. """ return calculate_keys_custom_exponent(p, q, DEFAULT_EXPONENT) def gen_keys(nbits, getprime_func, accurate=True, exponent=DEFAULT_EXPONENT): """Generate RSA keys of nbits bits. Returns (p, q, e, d). Note: this can take a long time, depending on the key size. :param nbits: the total number of bits in ``p`` and ``q``. Both ``p`` and ``q`` will use ``nbits/2`` bits. :param getprime_func: either :py:func:`rsa.prime.getprime` or a function with similar signature. :param exponent: the exponent for the key; only change this if you know what you're doing, as the exponent influences how difficult your private key can be cracked. A very common choice for e is 65537. :type exponent: int """ # Regenerate p and q values, until calculate_keys doesn't raise a # ValueError. while True: (p, q) = find_p_q(nbits // 2, getprime_func, accurate) try: (e, d) = calculate_keys_custom_exponent(p, q, exponent=exponent) break except ValueError: pass return p, q, e, d def newkeys(nbits, accurate=True, poolsize=1, exponent=DEFAULT_EXPONENT): """Generates public and private keys, and returns them as (pub, priv). The public key is also known as the 'encryption key', and is a :py:class:`rsa.PublicKey` object. The private key is also known as the 'decryption key' and is a :py:class:`rsa.PrivateKey` object. :param nbits: the number of bits required to store ``n = pq``. :param accurate: when True, ``n`` will have exactly the number of bits you asked for. However, this makes key generation much slower. When False, `n`` may have slightly less bits. :param poolsize: the number of processes to use to generate the prime numbers. If set to a number > 1, a parallel algorithm will be used. This requires Python 2.6 or newer. :param exponent: the exponent for the key; only change this if you know what you're doing, as the exponent influences how difficult your private key can be cracked. A very common choice for e is 65537. :type exponent: int :returns: a tuple (:py:class:`rsa.PublicKey`, :py:class:`rsa.PrivateKey`) The ``poolsize`` parameter was added in Python-RSA 3.1* and requires Python 2.6 or newer. """ if nbits < 16: raise ValueError('Key too small') if poolsize < 1: raise ValueError('Pool size (%i) should be >= 1' % poolsize) # Determine which getprime function to use if poolsize > 1: from rsa import parallel import functools getprime_func = functools.partial(parallel.getprime, poolsize=poolsize) else: getprime_func = rsa.prime.getprime # Generate the key components (p, q, e, d) = gen_keys(nbits, getprime_func, accurate=accurate, exponent=exponent) # Create the key objects n = p * q return ( PublicKey(n, e), PrivateKey(n, e, d, p, q) ) __all__ = ['PublicKey', 'PrivateKey', 'newkeys'] if __name__ == '__main__': import doctest try: for count in range(100): (failures, tests) = doctest.testmod() if failures: break if (count % 10 == 0 and count) or count == 1: print('%i times' % count) except KeyboardInterrupt: print('Aborted') else: print('Doctests done')	23.96 KB	2021-04-05 15:08
📄 machine_size.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Detection of 32-bit and 64-bit machines and byte alignment.""" import sys MAX_INT = sys.maxsize MAX_INT64 = (1 << 63) - 1 MAX_INT32 = (1 << 31) - 1 MAX_INT16 = (1 << 15) - 1 # Determine the word size of the processor. if MAX_INT == MAX_INT64: # 64-bit processor. MACHINE_WORD_SIZE = 64 elif MAX_INT == MAX_INT32: # 32-bit processor. MACHINE_WORD_SIZE = 32 else: # Else we just assume 64-bit processor keeping up with modern times. MACHINE_WORD_SIZE = 64 def get_word_alignment(num, force_arch=64, _machine_word_size=MACHINE_WORD_SIZE): """ Returns alignment details for the given number based on the platform Python is running on. :param num: Unsigned integral number. :param force_arch: If you don't want to use 64-bit unsigned chunks, set this to anything other than 64. 32-bit chunks will be preferred then. Default 64 will be used when on a 64-bit machine. :param _machine_word_size: (Internal) The machine word size used for alignment. :returns: 4-tuple:: (word_bits, word_bytes, max_uint, packing_format_type) """ max_uint64 = 0xffffffffffffffff max_uint32 = 0xffffffff max_uint16 = 0xffff max_uint8 = 0xff if force_arch == 64 and _machine_word_size >= 64 and num > max_uint32: # 64-bit unsigned integer. return 64, 8, max_uint64, "Q" elif num > max_uint16: # 32-bit unsigned integer return 32, 4, max_uint32, "L" elif num > max_uint8: # 16-bit unsigned integer. return 16, 2, max_uint16, "H" else: # 8-bit unsigned integer. return 8, 1, max_uint8, "B"	2.3 KB	2021-04-05 15:08
📄 parallel.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Functions for parallel computation on multiple cores. Introduced in Python-RSA 3.1. .. note:: Requires Python 2.6 or newer. """ from __future__ import print_function import multiprocessing as mp from rsa._compat import range import rsa.prime import rsa.randnum def _find_prime(nbits, pipe): while True: integer = rsa.randnum.read_random_odd_int(nbits) # Test for primeness if rsa.prime.is_prime(integer): pipe.send(integer) return def getprime(nbits, poolsize): """Returns a prime number that can be stored in 'nbits' bits. Works in multiple threads at the same time. >>> p = getprime(128, 3) >>> rsa.prime.is_prime(p-1) False >>> rsa.prime.is_prime(p) True >>> rsa.prime.is_prime(p+1) False >>> from rsa import common >>> common.bit_size(p) == 128 True """ (pipe_recv, pipe_send) = mp.Pipe(duplex=False) # Create processes try: procs = [mp.Process(target=_find_prime, args=(nbits, pipe_send)) for _ in range(poolsize)] # Start processes for p in procs: p.start() result = pipe_recv.recv() finally: pipe_recv.close() pipe_send.close() # Terminate processes for p in procs: p.terminate() return result __all__ = ['getprime'] if __name__ == '__main__': print('Running doctests 1000x or until failure') import doctest for count in range(100): (failures, tests) = doctest.testmod() if failures: break if count % 10 == 0 and count: print('%i times' % count) print('Doctests done')	2.27 KB	2021-04-05 15:08
📄 pem.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Functions that load and write PEM-encoded files.""" import base64 from rsa._compat import is_bytes, range def _markers(pem_marker): """ Returns the start and end PEM markers, as bytes. """ if not is_bytes(pem_marker): pem_marker = pem_marker.encode('ascii') return (b'-----BEGIN ' + pem_marker + b'-----', b'-----END ' + pem_marker + b'-----') def load_pem(contents, pem_marker): """Loads a PEM file. :param contents: the contents of the file to interpret :param pem_marker: the marker of the PEM content, such as 'RSA PRIVATE KEY' when your file has '-----BEGIN RSA PRIVATE KEY-----' and '-----END RSA PRIVATE KEY-----' markers. :return: the base64-decoded content between the start and end markers. @raise ValueError: when the content is invalid, for example when the start marker cannot be found. """ # We want bytes, not text. If it's text, it can be converted to ASCII bytes. if not is_bytes(contents): contents = contents.encode('ascii') (pem_start, pem_end) = _markers(pem_marker) pem_lines = [] in_pem_part = False for line in contents.splitlines(): line = line.strip() # Skip empty lines if not line: continue # Handle start marker if line == pem_start: if in_pem_part: raise ValueError('Seen start marker "%s" twice' % pem_start) in_pem_part = True continue # Skip stuff before first marker if not in_pem_part: continue # Handle end marker if in_pem_part and line == pem_end: in_pem_part = False break # Load fields if b':' in line: continue pem_lines.append(line) # Do some sanity checks if not pem_lines: raise ValueError('No PEM start marker "%s" found' % pem_start) if in_pem_part: raise ValueError('No PEM end marker "%s" found' % pem_end) # Base64-decode the contents pem = b''.join(pem_lines) return base64.standard_b64decode(pem) def save_pem(contents, pem_marker): """Saves a PEM file. :param contents: the contents to encode in PEM format :param pem_marker: the marker of the PEM content, such as 'RSA PRIVATE KEY' when your file has '-----BEGIN RSA PRIVATE KEY-----' and '-----END RSA PRIVATE KEY-----' markers. :return: the base64-encoded content between the start and end markers, as bytes. """ (pem_start, pem_end) = _markers(pem_marker) b64 = base64.standard_b64encode(contents).replace(b'\n', b'') pem_lines = [pem_start] for block_start in range(0, len(b64), 64): block = b64[block_start:block_start + 64] pem_lines.append(block) pem_lines.append(pem_end) pem_lines.append(b'') return b'\n'.join(pem_lines)	3.48 KB	2021-04-05 15:08
📄 pkcs1.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Functions for PKCS#1 version 1.5 encryption and signing This module implements certain functionality from PKCS#1 version 1.5. For a very clear example, read http://www.di-mgt.com.au/rsa_alg.html#pkcs1schemes At least 8 bytes of random padding is used when encrypting a message. This makes these methods much more secure than the ones in the ``rsa`` module. WARNING: this module leaks information when decryption fails. The exceptions that are raised contain the Python traceback information, which can be used to deduce where in the process the failure occurred. DO NOT PASS SUCH INFORMATION to your users. """ import hashlib import os from rsa._compat import range from rsa import common, transform, core # ASN.1 codes that describe the hash algorithm used. HASH_ASN1 = { 'MD5': b'\x30\x20\x30\x0c\x06\x08\x2a\x86\x48\x86\xf7\x0d\x02\x05\x05\x00\x04\x10', 'SHA-1': b'\x30\x21\x30\x09\x06\x05\x2b\x0e\x03\x02\x1a\x05\x00\x04\x14', 'SHA-224': b'\x30\x2d\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x04\x05\x00\x04\x1c', 'SHA-256': b'\x30\x31\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x01\x05\x00\x04\x20', 'SHA-384': b'\x30\x41\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x02\x05\x00\x04\x30', 'SHA-512': b'\x30\x51\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x03\x05\x00\x04\x40', } HASH_METHODS = { 'MD5': hashlib.md5, 'SHA-1': hashlib.sha1, 'SHA-224': hashlib.sha224, 'SHA-256': hashlib.sha256, 'SHA-384': hashlib.sha384, 'SHA-512': hashlib.sha512, } class CryptoError(Exception): """Base class for all exceptions in this module.""" class DecryptionError(CryptoError): """Raised when decryption fails.""" class VerificationError(CryptoError): """Raised when verification fails.""" def _pad_for_encryption(message, target_length): r"""Pads the message for encryption, returning the padded message. :return: 00 02 RANDOM_DATA 00 MESSAGE >>> block = _pad_for_encryption(b'hello', 16) >>> len(block) 16 >>> block[0:2] b'\x00\x02' >>> block[-6:] b'\x00hello' """ max_msglength = target_length - 11 msglength = len(message) if msglength > max_msglength: raise OverflowError('%i bytes needed for message, but there is only' ' space for %i' % (msglength, max_msglength)) # Get random padding padding = b'' padding_length = target_length - msglength - 3 # We remove 0-bytes, so we'll end up with less padding than we've asked for, # so keep adding data until we're at the correct length. while len(padding) < padding_length: needed_bytes = padding_length - len(padding) # Always read at least 8 bytes more than we need, and trim off the rest # after removing the 0-bytes. This increases the chance of getting # enough bytes, especially when needed_bytes is small new_padding = os.urandom(needed_bytes + 5) new_padding = new_padding.replace(b'\x00', b'') padding = padding + new_padding[:needed_bytes] assert len(padding) == padding_length return b''.join([b'\x00\x02', padding, b'\x00', message]) def _pad_for_signing(message, target_length): r"""Pads the message for signing, returning the padded message. The padding is always a repetition of FF bytes. :return: 00 01 PADDING 00 MESSAGE >>> block = _pad_for_signing(b'hello', 16) >>> len(block) 16 >>> block[0:2] b'\x00\x01' >>> block[-6:] b'\x00hello' >>> block[2:-6] b'\xff\xff\xff\xff\xff\xff\xff\xff' """ max_msglength = target_length - 11 msglength = len(message) if msglength > max_msglength: raise OverflowError('%i bytes needed for message, but there is only' ' space for %i' % (msglength, max_msglength)) padding_length = target_length - msglength - 3 return b''.join([b'\x00\x01', padding_length * b'\xff', b'\x00', message]) def encrypt(message, pub_key): """Encrypts the given message using PKCS#1 v1.5 :param message: the message to encrypt. Must be a byte string no longer than ``k-11`` bytes, where ``k`` is the number of bytes needed to encode the ``n`` component of the public key. :param pub_key: the :py:class:`rsa.PublicKey` to encrypt with. :raise OverflowError: when the message is too large to fit in the padded block. >>> from rsa import key, common >>> (pub_key, priv_key) = key.newkeys(256) >>> message = b'hello' >>> crypto = encrypt(message, pub_key) The crypto text should be just as long as the public key 'n' component: >>> len(crypto) == common.byte_size(pub_key.n) True """ keylength = common.byte_size(pub_key.n) padded = _pad_for_encryption(message, keylength) payload = transform.bytes2int(padded) encrypted = core.encrypt_int(payload, pub_key.e, pub_key.n) block = transform.int2bytes(encrypted, keylength) return block def decrypt(crypto, priv_key): r"""Decrypts the given message using PKCS#1 v1.5 The decryption is considered 'failed' when the resulting cleartext doesn't start with the bytes 00 02, or when the 00 byte between the padding and the message cannot be found. :param crypto: the crypto text as returned by :py:func:`rsa.encrypt` :param priv_key: the :py:class:`rsa.PrivateKey` to decrypt with. :raise DecryptionError: when the decryption fails. No details are given as to why the code thinks the decryption fails, as this would leak information about the private key. >>> import rsa >>> (pub_key, priv_key) = rsa.newkeys(256) It works with strings: >>> crypto = encrypt(b'hello', pub_key) >>> decrypt(crypto, priv_key) b'hello' And with binary data: >>> crypto = encrypt(b'\x00\x00\x00\x00\x01', pub_key) >>> decrypt(crypto, priv_key) b'\x00\x00\x00\x00\x01' Altering the encrypted information will likely cause a :py:class:`rsa.pkcs1.DecryptionError`. If you want to be sure, use :py:func:`rsa.sign`. .. warning:: Never display the stack trace of a :py:class:`rsa.pkcs1.DecryptionError` exception. It shows where in the code the exception occurred, and thus leaks information about the key. It's only a tiny bit of information, but every bit makes cracking the keys easier. >>> crypto = encrypt(b'hello', pub_key) >>> crypto = crypto[0:5] + b'X' + crypto[6:] # change a byte >>> decrypt(crypto, priv_key) Traceback (most recent call last): ... rsa.pkcs1.DecryptionError: Decryption failed """ blocksize = common.byte_size(priv_key.n) encrypted = transform.bytes2int(crypto) decrypted = priv_key.blinded_decrypt(encrypted) cleartext = transform.int2bytes(decrypted, blocksize) # Detect leading zeroes in the crypto. These are not reflected in the # encrypted value (as leading zeroes do not influence the value of an # integer). This fixes CVE-2020-13757. if len(crypto) > blocksize: raise DecryptionError('Decryption failed') # If we can't find the cleartext marker, decryption failed. if cleartext[0:2] != b'\x00\x02': raise DecryptionError('Decryption failed') # Find the 00 separator between the padding and the message try: sep_idx = cleartext.index(b'\x00', 2) except ValueError: raise DecryptionError('Decryption failed') return cleartext[sep_idx + 1:] def sign_hash(hash_value, priv_key, hash_method): """Signs a precomputed hash with the private key. Hashes the message, then signs the hash with the given key. This is known as a "detached signature", because the message itself isn't altered. :param hash_value: A precomputed hash to sign (ignores message). Should be set to None if needing to hash and sign message. :param priv_key: the :py:class:`rsa.PrivateKey` to sign with :param hash_method: the hash method used on the message. Use 'MD5', 'SHA-1', 'SHA-224', SHA-256', 'SHA-384' or 'SHA-512'. :return: a message signature block. :raise OverflowError: if the private key is too small to contain the requested hash. """ # Get the ASN1 code for this hash method if hash_method not in HASH_ASN1: raise ValueError('Invalid hash method: %s' % hash_method) asn1code = HASH_ASN1[hash_method] # Encrypt the hash with the private key cleartext = asn1code + hash_value keylength = common.byte_size(priv_key.n) padded = _pad_for_signing(cleartext, keylength) payload = transform.bytes2int(padded) encrypted = priv_key.blinded_encrypt(payload) block = transform.int2bytes(encrypted, keylength) return block def sign(message, priv_key, hash_method): """Signs the message with the private key. Hashes the message, then signs the hash with the given key. This is known as a "detached signature", because the message itself isn't altered. :param message: the message to sign. Can be an 8-bit string or a file-like object. If ``message`` has a ``read()`` method, it is assumed to be a file-like object. :param priv_key: the :py:class:`rsa.PrivateKey` to sign with :param hash_method: the hash method used on the message. Use 'MD5', 'SHA-1', 'SHA-224', SHA-256', 'SHA-384' or 'SHA-512'. :return: a message signature block. :raise OverflowError: if the private key is too small to contain the requested hash. """ msg_hash = compute_hash(message, hash_method) return sign_hash(msg_hash, priv_key, hash_method) def verify(message, signature, pub_key): """Verifies that the signature matches the message. The hash method is detected automatically from the signature. :param message: the signed message. Can be an 8-bit string or a file-like object. If ``message`` has a ``read()`` method, it is assumed to be a file-like object. :param signature: the signature block, as created with :py:func:`rsa.sign`. :param pub_key: the :py:class:`rsa.PublicKey` of the person signing the message. :raise VerificationError: when the signature doesn't match the message. :returns: the name of the used hash. """ keylength = common.byte_size(pub_key.n) encrypted = transform.bytes2int(signature) decrypted = core.decrypt_int(encrypted, pub_key.e, pub_key.n) clearsig = transform.int2bytes(decrypted, keylength) # Get the hash method method_name = _find_method_hash(clearsig) message_hash = compute_hash(message, method_name) # Reconstruct the expected padded hash cleartext = HASH_ASN1[method_name] + message_hash expected = _pad_for_signing(cleartext, keylength) if len(signature) != keylength: raise VerificationError('Verification failed') # Compare with the signed one if expected != clearsig: raise VerificationError('Verification failed') return method_name def find_signature_hash(signature, pub_key): """Returns the hash name detected from the signature. If you also want to verify the message, use :py:func:`rsa.verify()` instead. It also returns the name of the used hash. :param signature: the signature block, as created with :py:func:`rsa.sign`. :param pub_key: the :py:class:`rsa.PublicKey` of the person signing the message. :returns: the name of the used hash. """ keylength = common.byte_size(pub_key.n) encrypted = transform.bytes2int(signature) decrypted = core.decrypt_int(encrypted, pub_key.e, pub_key.n) clearsig = transform.int2bytes(decrypted, keylength) return _find_method_hash(clearsig) def yield_fixedblocks(infile, blocksize): """Generator, yields each block of ``blocksize`` bytes in the input file. :param infile: file to read and separate in blocks. :param blocksize: block size in bytes. :returns: a generator that yields the contents of each block """ while True: block = infile.read(blocksize) read_bytes = len(block) if read_bytes == 0: break yield block if read_bytes < blocksize: break def compute_hash(message, method_name): """Returns the message digest. :param message: the signed message. Can be an 8-bit string or a file-like object. If ``message`` has a ``read()`` method, it is assumed to be a file-like object. :param method_name: the hash method, must be a key of :py:const:`HASH_METHODS`. """ if method_name not in HASH_METHODS: raise ValueError('Invalid hash method: %s' % method_name) method = HASH_METHODS[method_name] hasher = method() if hasattr(message, 'read') and hasattr(message.read, '__call__'): # read as 1K blocks for block in yield_fixedblocks(message, 1024): hasher.update(block) else: # hash the message object itself. hasher.update(message) return hasher.digest() def _find_method_hash(clearsig): """Finds the hash method. :param clearsig: full padded ASN1 and hash. :return: the used hash method. :raise VerificationFailed: when the hash method cannot be found """ for (hashname, asn1code) in HASH_ASN1.items(): if asn1code in clearsig: return hashname raise VerificationError('Verification failed') __all__ = ['encrypt', 'decrypt', 'sign', 'verify', 'DecryptionError', 'VerificationError', 'CryptoError'] if __name__ == '__main__': print('Running doctests 1000x or until failure') import doctest for count in range(1000): (failures, tests) = doctest.testmod() if failures: break if count % 100 == 0 and count: print('%i times' % count) print('Doctests done')	14.35 KB	2021-04-05 15:08
📄 pkcs1_v2.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Functions for PKCS#1 version 2 encryption and signing This module implements certain functionality from PKCS#1 version 2. Main documentation is RFC 2437: https://tools.ietf.org/html/rfc2437 """ from rsa._compat import range from rsa import ( common, pkcs1, transform, ) def mgf1(seed, length, hasher='SHA-1'): """ MGF1 is a Mask Generation Function based on a hash function. A mask generation function takes an octet string of variable length and a desired output length as input, and outputs an octet string of the desired length. The plaintext-awareness of RSAES-OAEP relies on the random nature of the output of the mask generation function, which in turn relies on the random nature of the underlying hash. :param bytes seed: seed from which mask is generated, an octet string :param int length: intended length in octets of the mask, at most 2^32(hLen) :param str hasher: hash function (hLen denotes the length in octets of the hash function output) :return: mask, an octet string of length `length` :rtype: bytes :raise OverflowError: when `length` is too large for the specified `hasher` :raise ValueError: when specified `hasher` is invalid """ try: hash_length = pkcs1.HASH_METHODS[hasher]().digest_size except KeyError: raise ValueError( 'Invalid `hasher` specified. Please select one of: {hash_list}'.format( hash_list=', '.join(sorted(pkcs1.HASH_METHODS.keys())) ) ) # If l > 2^32(hLen), output "mask too long" and stop. if length > (2*32 hash_length): raise OverflowError( "Desired length should be at most 2**32 times the hasher's output " "length ({hash_length} for {hasher} function)".format( hash_length=hash_length, hasher=hasher, ) ) # Looping `counter` from 0 to ceil(l / hLen)-1, build `output` based on the # hashes formed by (`seed` + C), being `C` an octet string of length 4 # generated by converting `counter` with the primitive I2OSP output = b''.join( pkcs1.compute_hash( seed + transform.int2bytes(counter, fill_size=4), method_name=hasher, ) for counter in range(common.ceil_div(length, hash_length) + 1) ) # Output the leading `length` octets of `output` as the octet string mask. return output[:length] __all__ = [ 'mgf1', ] if __name__ == '__main__': print('Running doctests 1000x or until failure') import doctest for count in range(1000): (failures, tests) = doctest.testmod() if failures: break if count % 100 == 0 and count: print('%i times' % count) print('Doctests done')	3.38 KB	2021-04-05 15:08
📄 prime.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Numerical functions related to primes. Implementation based on the book Algorithm Design by Michael T. Goodrich and Roberto Tamassia, 2002. """ from rsa._compat import range import rsa.common import rsa.randnum __all__ = ['getprime', 'are_relatively_prime'] def gcd(p, q): """Returns the greatest common divisor of p and q >>> gcd(48, 180) 12 """ while q != 0: (p, q) = (q, p % q) return p def get_primality_testing_rounds(number): """Returns minimum number of rounds for Miller-Rabing primality testing, based on number bitsize. According to NIST FIPS 186-4, Appendix C, Table C.3, minimum number of rounds of M-R testing, using an error probability of 2 ** (-100), for different p, q bitsizes are: * p, q bitsize: 512; rounds: 7 * p, q bitsize: 1024; rounds: 4 * p, q bitsize: 1536; rounds: 3 See: http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf """ # Calculate number bitsize. bitsize = rsa.common.bit_size(number) # Set number of rounds. if bitsize >= 1536: return 3 if bitsize >= 1024: return 4 if bitsize >= 512: return 7 # For smaller bitsizes, set arbitrary number of rounds. return 10 def miller_rabin_primality_testing(n, k): """Calculates whether n is composite (which is always correct) or prime (which theoretically is incorrect with error probability 4-k), by applying Miller-Rabin primality testing. For reference and implementation example, see: https://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test :param n: Integer to be tested for primality. :type n: int :param k: Number of rounds (witnesses) of Miller-Rabin testing. :type k: int :return: False if the number is composite, True if it's probably prime. :rtype: bool """ # prevent potential infinite loop when d = 0 if n < 2: return False # Decompose (n - 1) to write it as (2 r) * d # While d is even, divide it by 2 and increase the exponent. d = n - 1 r = 0 while not (d & 1): r += 1 d >>= 1 # Test k witnesses. for _ in range(k): # Generate random integer a, where 2 <= a <= (n - 2) a = rsa.randnum.randint(n - 3) + 1 x = pow(a, d, n) if x == 1 or x == n - 1: continue for _ in range(r - 1): x = pow(x, 2, n) if x == 1: # n is composite. return False if x == n - 1: # Exit inner loop and continue with next witness. break else: # If loop doesn't break, n is composite. return False return True def is_prime(number): """Returns True if the number is prime, and False otherwise. >>> is_prime(2) True >>> is_prime(42) False >>> is_prime(41) True """ # Check for small numbers. if number < 10: return number in {2, 3, 5, 7} # Check for even numbers. if not (number & 1): return False # Calculate minimum number of rounds. k = get_primality_testing_rounds(number) # Run primality testing with (minimum + 1) rounds. return miller_rabin_primality_testing(number, k + 1) def getprime(nbits): """Returns a prime number that can be stored in 'nbits' bits. >>> p = getprime(128) >>> is_prime(p-1) False >>> is_prime(p) True >>> is_prime(p+1) False >>> from rsa import common >>> common.bit_size(p) == 128 True """ assert nbits > 3 # the loop wil hang on too small numbers while True: integer = rsa.randnum.read_random_odd_int(nbits) # Test for primeness if is_prime(integer): return integer # Retry if not prime def are_relatively_prime(a, b): """Returns True if a and b are relatively prime, and False if they are not. >>> are_relatively_prime(2, 3) True >>> are_relatively_prime(2, 4) False """ d = gcd(a, b) return d == 1 if __name__ == '__main__': print('Running doctests 1000x or until failure') import doctest for count in range(1000): (failures, tests) = doctest.testmod() if failures: break if count % 100 == 0 and count: print('%i times' % count) print('Doctests done')	4.95 KB	2021-04-05 15:08
📄 randnum.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Functions for generating random numbers.""" # Source inspired by code by Yesudeep Mangalapilly <yesudeep@gmail.com> import os from rsa import common, transform from rsa._compat import byte def read_random_bits(nbits): """Reads 'nbits' random bits. If nbits isn't a whole number of bytes, an extra byte will be appended with only the lower bits set. """ nbytes, rbits = divmod(nbits, 8) # Get the random bytes randomdata = os.urandom(nbytes) # Add the remaining random bits if rbits > 0: randomvalue = ord(os.urandom(1)) randomvalue >>= (8 - rbits) randomdata = byte(randomvalue) + randomdata return randomdata def read_random_int(nbits): """Reads a random integer of approximately nbits bits. """ randomdata = read_random_bits(nbits) value = transform.bytes2int(randomdata) # Ensure that the number is large enough to just fill out the required # number of bits. value \|= 1 << (nbits - 1) return value def read_random_odd_int(nbits): """Reads a random odd integer of approximately nbits bits. >>> read_random_odd_int(512) & 1 1 """ value = read_random_int(nbits) # Make sure it's odd return value \| 1 def randint(maxvalue): """Returns a random integer x with 1 <= x <= maxvalue May take a very long time in specific situations. If maxvalue needs N bits to store, the closer maxvalue is to (2 ** N) - 1, the faster this function is. """ bit_size = common.bit_size(maxvalue) tries = 0 while True: value = read_random_int(bit_size) if value <= maxvalue: break if tries % 10 == 0 and tries: # After a lot of tries to get the right number of bits but still # smaller than maxvalue, decrease the number of bits by 1. That'll # dramatically increase the chances to get a large enough number. bit_size -= 1 tries += 1 return value	2.58 KB	2021-04-05 15:08
📄 transform.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Data transformation functions. From bytes to a number, number to bytes, etc. """ from __future__ import absolute_import import binascii from struct import pack from rsa._compat import byte, is_integer from rsa import common, machine_size def bytes2int(raw_bytes): r"""Converts a list of bytes or an 8-bit string to an integer. When using unicode strings, encode it to some encoding like UTF8 first. >>> (((128 * 256) + 64) * 256) + 15 8405007 >>> bytes2int(b'\x80@\x0f') 8405007 """ return int(binascii.hexlify(raw_bytes), 16) def _int2bytes(number, block_size=None): r"""Converts a number to a string of bytes. Usage:: >>> _int2bytes(123456789) b'\x07[\xcd\x15' >>> bytes2int(_int2bytes(123456789)) 123456789 >>> _int2bytes(123456789, 6) b'\x00\x00\x07[\xcd\x15' >>> bytes2int(_int2bytes(123456789, 128)) 123456789 >>> _int2bytes(123456789, 3) Traceback (most recent call last): ... OverflowError: Needed 4 bytes for number, but block size is 3 @param number: the number to convert @param block_size: the number of bytes to output. If the number encoded to bytes is less than this, the block will be zero-padded. When not given, the returned block is not padded. @throws OverflowError when block_size is given and the number takes up more bytes than fit into the block. """ # Type checking if not is_integer(number): raise TypeError("You must pass an integer for 'number', not %s" % number.__class__) if number < 0: raise ValueError('Negative numbers cannot be used: %i' % number) # Do some bounds checking if number == 0: needed_bytes = 1 raw_bytes = [b'\x00'] else: needed_bytes = common.byte_size(number) raw_bytes = [] # You cannot compare None > 0 in Python 3x. It will fail with a TypeError. if block_size and block_size > 0: if needed_bytes > block_size: raise OverflowError('Needed %i bytes for number, but block size ' 'is %i' % (needed_bytes, block_size)) # Convert the number to bytes. while number > 0: raw_bytes.insert(0, byte(number & 0xFF)) number >>= 8 # Pad with zeroes to fill the block if block_size and block_size > 0: padding = (block_size - needed_bytes) * b'\x00' else: padding = b'' return padding + b''.join(raw_bytes) def bytes_leading(raw_bytes, needle=b'\x00'): """ Finds the number of prefixed byte occurrences in the haystack. Useful when you want to deal with padding. :param raw_bytes: Raw bytes. :param needle: The byte to count. Default \x00. :returns: The number of leading needle bytes. """ leading = 0 # Indexing keeps compatibility between Python 2.x and Python 3.x _byte = needle[0] for x in raw_bytes: if x == _byte: leading += 1 else: break return leading def int2bytes(number, fill_size=None, chunk_size=None, overflow=False): """ Convert an unsigned integer to bytes (base-256 representation):: Does not preserve leading zeros if you don't specify a chunk size or fill size. .. NOTE: You must not specify both fill_size and chunk_size. Only one of them is allowed. :param number: Integer value :param fill_size: If the optional fill size is given the length of the resulting byte string is expected to be the fill size and will be padded with prefix zero bytes to satisfy that length. :param chunk_size: If optional chunk size is given and greater than zero, pad the front of the byte string with binary zeros so that the length is a multiple of ``chunk_size``. :param overflow: ``False`` (default). If this is ``True``, no ``OverflowError`` will be raised when the fill_size is shorter than the length of the generated byte sequence. Instead the byte sequence will be returned as is. :returns: Raw bytes (base-256 representation). :raises: ``OverflowError`` when fill_size is given and the number takes up more bytes than fit into the block. This requires the ``overflow`` argument to this function to be set to ``False`` otherwise, no error will be raised. """ if number < 0: raise ValueError("Number must be an unsigned integer: %d" % number) if fill_size and chunk_size: raise ValueError("You can either fill or pad chunks, but not both") # Ensure these are integers. number & 1 raw_bytes = b'' # Pack the integer one machine word at a time into bytes. num = number word_bits, _, max_uint, pack_type = machine_size.get_word_alignment(num) pack_format = ">%s" % pack_type while num > 0: raw_bytes = pack(pack_format, num & max_uint) + raw_bytes num >>= word_bits # Obtain the index of the first non-zero byte. zero_leading = bytes_leading(raw_bytes) if number == 0: raw_bytes = b'\x00' # De-padding. raw_bytes = raw_bytes[zero_leading:] length = len(raw_bytes) if fill_size and fill_size > 0: if not overflow and length > fill_size: raise OverflowError( "Need %d bytes for number, but fill size is %d" % (length, fill_size) ) raw_bytes = raw_bytes.rjust(fill_size, b'\x00') elif chunk_size and chunk_size > 0: remainder = length % chunk_size if remainder: padding_size = chunk_size - remainder raw_bytes = raw_bytes.rjust(length + padding_size, b'\x00') return raw_bytes if __name__ == '__main__': import doctest doctest.testmod()	6.44 KB	2021-04-05 15:08
📄 util.py # -- coding: utf-8 -- # # Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # https://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Utility functions.""" from __future__ import with_statement, print_function import sys from optparse import OptionParser import rsa.key def private_to_public(): """Reads a private key and outputs the corresponding public key.""" # Parse the CLI options parser = OptionParser(usage='usage: %prog [options]', description='Reads a private key and outputs the ' 'corresponding public key. Both private and public keys use ' 'the format described in PKCS#1 v1.5') parser.add_option('-i', '--input', dest='infilename', type='string', help='Input filename. Reads from stdin if not specified') parser.add_option('-o', '--output', dest='outfilename', type='string', help='Output filename. Writes to stdout of not specified') parser.add_option('--inform', dest='inform', help='key format of input - default PEM', choices=('PEM', 'DER'), default='PEM') parser.add_option('--outform', dest='outform', help='key format of output - default PEM', choices=('PEM', 'DER'), default='PEM') (cli, cli_args) = parser.parse_args(sys.argv) # Read the input data if cli.infilename: print('Reading private key from %s in %s format' % (cli.infilename, cli.inform), file=sys.stderr) with open(cli.infilename, 'rb') as infile: in_data = infile.read() else: print('Reading private key from stdin in %s format' % cli.inform, file=sys.stderr) in_data = sys.stdin.read().encode('ascii') assert type(in_data) == bytes, type(in_data) # Take the public fields and create a public key priv_key = rsa.key.PrivateKey.load_pkcs1(in_data, cli.inform) pub_key = rsa.key.PublicKey(priv_key.n, priv_key.e) # Save to the output file out_data = pub_key.save_pkcs1(cli.outform) if cli.outfilename: print('Writing public key to %s in %s format' % (cli.outfilename, cli.outform), file=sys.stderr) with open(cli.outfilename, 'wb') as outfile: outfile.write(out_data) else: print('Writing public key to stdout in %s format' % cli.outform, file=sys.stderr) sys.stdout.write(out_data.decode('ascii'))	2.99 KB	2021-04-05 15:08

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