How Bona! : Pythonで学ぶRSAを利用したユーザー認証

opensslラッパー

pycryptoをインストールするのは案外大変だったので，多くの環境で既にインストールされていると思われるopensslを使って，RSAに関連する機能のラッパーを作成してみました．
rsabyopenssl.py←右クリックで保存できます．

#!/usr/bin/evn python
#conding: utf-8

import subprocess

def subprocess_pipe(cmd, inbuff):
	p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
	return p.communicate(inbuff)

def genrsa(nbits, private_key_file, public_key_file, passphrase=None):
	if( passphrase == None ):
		pin = ''
		pout = ''
	else:
		pin = ' -passin pass:%s ' % passphrase
		pout = ' -des3 -passout pass:%s ' % passphrase

	cmd = 'openssl genrsa %s | openssl rsa -out %s %s' % ( str(nbits), private_key_file, pout)
	subprocess.call(cmd, shell=True)
	
	cmd = 'openssl rsa %s -in %s -pubout -out %s' % ( pin, private_key_file, public_key_file )
	subprocess.call(cmd, shell=True)

def encrypto( public_key_file, buff ):
	cmd = 'openssl rsautl -encrypt -pubin -inkey %s' % public_key_file
	response = subprocess_pipe( cmd, buff )
	return response

def decrypto( private_key_file, buff, passphrase=None ):
	if( passphrase == None ):
		pin = ''
	else:
		pin = ' -passin pass:%s ' % passphrase
	
	cmd = 'openssl rsautl -decrypt %s -inkey %s' % ( pin, private_key_file )
	response = subprocess_pipe( cmd, buff )
	return response

def rand( nbytes ):
	cmd = 'openssl rand ' + str(nbytes)
	return subprocess.check_output( cmd, shell=True )

if(__name__=='__main__'):
	import base64
	import sys
	nbits = 2048
	private_key_file = 'rsa.pri'
	public_key_file = 'rsa.pub'
	passphrase = 'Hello_RSA!'
	text = 'You got money!'
	
	genrsa(1024, private_key_file, public_key_file, passphrase )
	
	print text
	
	enc, ret = encrypto( public_key_file, text )
	if( ret != '' ):
		print 'encrypto error'
		sys.exit()
	print base64.b64encode(enc)

	dec, ret = decrypto( private_key_file, enc, passphrase )
	if( ret != '' ):
		print 'decrypto error'
		sys.exit()
	print dec