292 lines
9.7 KiB
Python
292 lines
9.7 KiB
Python
# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# https://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Commandline scripts.
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These scripts are called by the executables defined in setup.py.
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"""
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import abc
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import sys
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import typing
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import optparse
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import rsa
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import rsa.key
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import rsa.pkcs1
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HASH_METHODS = sorted(rsa.pkcs1.HASH_METHODS.keys())
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Indexable = typing.Union[typing.Tuple, typing.List[str]]
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def keygen() -> None:
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"""Key generator."""
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# Parse the CLI options
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parser = optparse.OptionParser(usage='usage: %prog [options] keysize',
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description='Generates a new RSA keypair of "keysize" bits.')
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parser.add_option('--pubout', type='string',
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help='Output filename for the public key. The public key is '
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'not saved if this option is not present. You can use '
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'pyrsa-priv2pub to create the public key file later.')
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parser.add_option('-o', '--out', type='string',
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help='Output filename for the private key. The key is '
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'written to stdout if this option is not present.')
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parser.add_option('--form',
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help='key format of the private and public keys - default PEM',
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choices=('PEM', 'DER'), default='PEM')
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(cli, cli_args) = parser.parse_args(sys.argv[1:])
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if len(cli_args) != 1:
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parser.print_help()
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raise SystemExit(1)
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try:
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keysize = int(cli_args[0])
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except ValueError:
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parser.print_help()
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print('Not a valid number: %s' % cli_args[0], file=sys.stderr)
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raise SystemExit(1)
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print('Generating %i-bit key' % keysize, file=sys.stderr)
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(pub_key, priv_key) = rsa.newkeys(keysize)
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# Save public key
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if cli.pubout:
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print('Writing public key to %s' % cli.pubout, file=sys.stderr)
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data = pub_key.save_pkcs1(format=cli.form)
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with open(cli.pubout, 'wb') as outfile:
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outfile.write(data)
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# Save private key
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data = priv_key.save_pkcs1(format=cli.form)
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if cli.out:
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print('Writing private key to %s' % cli.out, file=sys.stderr)
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with open(cli.out, 'wb') as outfile:
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outfile.write(data)
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else:
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print('Writing private key to stdout', file=sys.stderr)
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sys.stdout.buffer.write(data)
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class CryptoOperation(metaclass=abc.ABCMeta):
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"""CLI callable that operates with input, output, and a key."""
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keyname = 'public' # or 'private'
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usage = 'usage: %%prog [options] %(keyname)s_key'
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description = ''
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operation = 'decrypt'
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operation_past = 'decrypted'
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operation_progressive = 'decrypting'
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input_help = 'Name of the file to %(operation)s. Reads from stdin if ' \
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'not specified.'
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output_help = 'Name of the file to write the %(operation_past)s file ' \
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'to. Written to stdout if this option is not present.'
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expected_cli_args = 1
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has_output = True
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key_class = rsa.PublicKey # type: typing.Type[rsa.key.AbstractKey]
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def __init__(self) -> None:
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self.usage = self.usage % self.__class__.__dict__
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self.input_help = self.input_help % self.__class__.__dict__
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self.output_help = self.output_help % self.__class__.__dict__
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@abc.abstractmethod
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def perform_operation(self, indata: bytes, key: rsa.key.AbstractKey,
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cli_args: Indexable) -> typing.Any:
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"""Performs the program's operation.
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Implement in a subclass.
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:returns: the data to write to the output.
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"""
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def __call__(self) -> None:
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"""Runs the program."""
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(cli, cli_args) = self.parse_cli()
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key = self.read_key(cli_args[0], cli.keyform)
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indata = self.read_infile(cli.input)
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print(self.operation_progressive.title(), file=sys.stderr)
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outdata = self.perform_operation(indata, key, cli_args)
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if self.has_output:
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self.write_outfile(outdata, cli.output)
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def parse_cli(self) -> typing.Tuple[optparse.Values, typing.List[str]]:
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"""Parse the CLI options
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:returns: (cli_opts, cli_args)
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"""
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parser = optparse.OptionParser(usage=self.usage, description=self.description)
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parser.add_option('-i', '--input', type='string', help=self.input_help)
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if self.has_output:
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parser.add_option('-o', '--output', type='string', help=self.output_help)
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parser.add_option('--keyform',
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help='Key format of the %s key - default PEM' % self.keyname,
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choices=('PEM', 'DER'), default='PEM')
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(cli, cli_args) = parser.parse_args(sys.argv[1:])
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if len(cli_args) != self.expected_cli_args:
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parser.print_help()
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raise SystemExit(1)
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return cli, cli_args
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def read_key(self, filename: str, keyform: str) -> rsa.key.AbstractKey:
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"""Reads a public or private key."""
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print('Reading %s key from %s' % (self.keyname, filename), file=sys.stderr)
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with open(filename, 'rb') as keyfile:
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keydata = keyfile.read()
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return self.key_class.load_pkcs1(keydata, keyform)
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def read_infile(self, inname: str) -> bytes:
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"""Read the input file"""
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if inname:
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print('Reading input from %s' % inname, file=sys.stderr)
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with open(inname, 'rb') as infile:
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return infile.read()
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print('Reading input from stdin', file=sys.stderr)
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return sys.stdin.buffer.read()
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def write_outfile(self, outdata: bytes, outname: str) -> None:
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"""Write the output file"""
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if outname:
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print('Writing output to %s' % outname, file=sys.stderr)
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with open(outname, 'wb') as outfile:
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outfile.write(outdata)
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else:
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print('Writing output to stdout', file=sys.stderr)
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sys.stdout.buffer.write(outdata)
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class EncryptOperation(CryptoOperation):
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"""Encrypts a file."""
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keyname = 'public'
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description = ('Encrypts a file. The file must be shorter than the key '
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'length in order to be encrypted.')
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operation = 'encrypt'
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operation_past = 'encrypted'
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operation_progressive = 'encrypting'
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def perform_operation(self, indata: bytes, pub_key: rsa.key.AbstractKey,
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cli_args: Indexable = ()) -> bytes:
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"""Encrypts files."""
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assert isinstance(pub_key, rsa.key.PublicKey)
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return rsa.encrypt(indata, pub_key)
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class DecryptOperation(CryptoOperation):
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"""Decrypts a file."""
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keyname = 'private'
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description = ('Decrypts a file. The original file must be shorter than '
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'the key length in order to have been encrypted.')
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operation = 'decrypt'
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operation_past = 'decrypted'
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operation_progressive = 'decrypting'
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key_class = rsa.PrivateKey
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def perform_operation(self, indata: bytes, priv_key: rsa.key.AbstractKey,
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cli_args: Indexable = ()) -> bytes:
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"""Decrypts files."""
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assert isinstance(priv_key, rsa.key.PrivateKey)
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return rsa.decrypt(indata, priv_key)
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class SignOperation(CryptoOperation):
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"""Signs a file."""
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keyname = 'private'
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usage = 'usage: %%prog [options] private_key hash_method'
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description = ('Signs a file, outputs the signature. Choose the hash '
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'method from %s' % ', '.join(HASH_METHODS))
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operation = 'sign'
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operation_past = 'signature'
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operation_progressive = 'Signing'
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key_class = rsa.PrivateKey
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expected_cli_args = 2
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output_help = ('Name of the file to write the signature to. Written '
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'to stdout if this option is not present.')
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def perform_operation(self, indata: bytes, priv_key: rsa.key.AbstractKey,
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cli_args: Indexable) -> bytes:
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"""Signs files."""
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assert isinstance(priv_key, rsa.key.PrivateKey)
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hash_method = cli_args[1]
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if hash_method not in HASH_METHODS:
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raise SystemExit('Invalid hash method, choose one of %s' %
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', '.join(HASH_METHODS))
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return rsa.sign(indata, priv_key, hash_method)
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class VerifyOperation(CryptoOperation):
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"""Verify a signature."""
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keyname = 'public'
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usage = 'usage: %%prog [options] public_key signature_file'
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description = ('Verifies a signature, exits with status 0 upon success, '
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'prints an error message and exits with status 1 upon error.')
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operation = 'verify'
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operation_past = 'verified'
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operation_progressive = 'Verifying'
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key_class = rsa.PublicKey
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expected_cli_args = 2
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has_output = False
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def perform_operation(self, indata: bytes, pub_key: rsa.key.AbstractKey,
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cli_args: Indexable) -> None:
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"""Verifies files."""
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assert isinstance(pub_key, rsa.key.PublicKey)
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signature_file = cli_args[1]
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with open(signature_file, 'rb') as sigfile:
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signature = sigfile.read()
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try:
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rsa.verify(indata, signature, pub_key)
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except rsa.VerificationError:
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raise SystemExit('Verification failed.')
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print('Verification OK', file=sys.stderr)
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encrypt = EncryptOperation()
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decrypt = DecryptOperation()
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sign = SignOperation()
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verify = VerifyOperation()
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