| # -*- 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')) |