80 lines
3.0 KiB
Python
80 lines
3.0 KiB
Python
# -*- coding: utf-8 -*-
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#
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# 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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"""Utility functions."""
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from __future__ import with_statement, print_function
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import sys
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from optparse import OptionParser
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import rsa.key
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def private_to_public():
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"""Reads a private key and outputs the corresponding public key."""
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# Parse the CLI options
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parser = OptionParser(usage='usage: %prog [options]',
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description='Reads a private key and outputs the '
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'corresponding public key. Both private and public keys use '
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'the format described in PKCS#1 v1.5')
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parser.add_option('-i', '--input', dest='infilename', type='string',
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help='Input filename. Reads from stdin if not specified')
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parser.add_option('-o', '--output', dest='outfilename', type='string',
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help='Output filename. Writes to stdout of not specified')
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parser.add_option('--inform', dest='inform',
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help='key format of input - default PEM',
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choices=('PEM', 'DER'), default='PEM')
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parser.add_option('--outform', dest='outform',
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help='key format of output - default PEM',
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choices=('PEM', 'DER'), default='PEM')
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(cli, cli_args) = parser.parse_args(sys.argv)
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# Read the input data
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if cli.infilename:
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print('Reading private key from %s in %s format' %
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(cli.infilename, cli.inform), file=sys.stderr)
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with open(cli.infilename, 'rb') as infile:
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in_data = infile.read()
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else:
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print('Reading private key from stdin in %s format' % cli.inform,
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file=sys.stderr)
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in_data = sys.stdin.read().encode('ascii')
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assert type(in_data) == bytes, type(in_data)
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# Take the public fields and create a public key
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priv_key = rsa.key.PrivateKey.load_pkcs1(in_data, cli.inform)
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pub_key = rsa.key.PublicKey(priv_key.n, priv_key.e)
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# Save to the output file
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out_data = pub_key.save_pkcs1(cli.outform)
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if cli.outfilename:
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print('Writing public key to %s in %s format' %
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(cli.outfilename, cli.outform), file=sys.stderr)
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with open(cli.outfilename, 'wb') as outfile:
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outfile.write(out_data)
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else:
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print('Writing public key to stdout in %s format' % cli.outform,
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file=sys.stderr)
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sys.stdout.write(out_data.decode('ascii'))
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