RSA signature

rsa_sign.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import ConfigParser
from Crypto.Hash import SHA
from Crypto.PublicKey import RSA
from Crypto.Signature import PKCS1_v1_5
from base64 import b64encode

config = ConfigParser.ConfigParser()
config.readfp(open('config.ini'))

# test signature
#
# echo -n 'hello world' | openssl dgst -sha1 -sign private.pem | base64 > signature.txt
# base64 --decode -i signature.txt > signature-decoded.bin
# echo -n 'hello world' | openssl dgst -sha1 -verify public.pem -signature signature-decoded.bin

data = 'hello world'

key_file = config.get('secret', 'private_key_path')
print key_file

key = None
try:
    key = open(key_file, 'r').read()
except IOError:
    print 'private key not found'
    exit(1)

rsa_key = RSA.importKey(key)
signer = PKCS1_v1_5.new(rsa_key)

digest = SHA.new()
digest.update(data)

signature = b64encode(signer.sign(digest))
print signature