Added pyrsa-priv2pub CLI tool

1 files changed, 77 insertions, 0 deletions

diff --git a/rsa/util.py b/rsa/util.py
new file mode 100644
index 0000000..9c1c863
--- /dev/null
+++ b/rsa/util.py
@@ -0,0 +1,77 @@
+# -*- 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
+#
+#      http://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.'''
+
+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('--in', dest='infilename', type='string',
+            help='Input filename. Reads from stdin if not specified')
+    parser.add_option('--out', 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 >>sys.stderr, 'Reading private key from %s in %s format' % \
+            (cli.infilename, cli.inform)
+        with open(cli.infilename) as infile:
+            in_data = infile.read()
+    else:
+        print >>sys.stderr, 'Reading private key from stdin in %s format' % \
+            cli.inform
+        in_data = sys.stdin.read()
+
+
+    # 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 >>sys.stderr, 'Writing public key to %s in %s format' % \
+            (cli.outfilename, cli.outform)
+        with open(cli.outfilename, 'w') as outfile:
+            outfile.write(out_data)
+    else:
+        print >>sys.stderr, 'Writing public key to stdout in %s format' % \
+            cli.outform
+        sys.stdout.write(out_data)
+
+