example_strings.json

{
  "algorithms":"Failure in algorithm design",
  "bobs":"bobs",
  "Cats":"THIIIISSS ISS A SECRET"
}

string_crypto.py

import json
import sys
import re
import base64
import os.path
import getpass
from Crypto.Cipher import AES
from Crypto.Cipher import Random
from Crypto.Protocol.KDF import PBKDF2

def varnamevalid(s):
	return re.match(r"\w+") != None
	
def encrypted(key,s):
	iv=Random.new().read(AES.block_size)
	cipher=AES.new(key,AES.MODE_CFB, iv)
	msg=iv+cipher.encrypt(s)
	b64msg=base64.standard_b64encode(s)
	return "$LOGCODE["+b64msg+"]"
	
def decrypted(key,b64msg):
	msg=base64.standard_b64decode(b64msg)
	iv=msg[0:AES.block_size]
	ciphertext=msg[AES.block_size:]
	cipher=AES.new(key,AES.MODE_CFB.iv)
	return cipher.decrypt(ciphertext)

def encrypt(strings,password,prefix=""):
	key=PBKDF2(password,"cryptstrings")
	strdict=json.load(strings)
	header='#ifndef CRYPTSTRINGS_HPP\n#define CRYPTSTRINGS_HPP\n\n#include<string>\n\nnamespace cs {\n'
	content='#include "cryptstrings.hpp"\nnamespace cs {';
	for k,v in strdict.iteritems():
		if(varnamevalid(k)):
			decl='static const std::string '+k
			header+='extern '+decl+';\n'
			content+=decl+'="'+encrypted(v)+'";\n'
		else
			print 'Warning: "'+k+'" cannot be interpreted as a C++ variable, it will not be exported'
	header+="}\n#endif\n"
	content+="}\n"
	open(os.path.join(prefix,"cryptstring.hpp"),'w').write(header)
	open(os.path.join(prefix,"cryptstring.cpp"),'w').write(content)

def decrypt(file,password):
	key=PBKDF2(password,"cryptstrings")
	def decsub(mo):
		return decrypted(key,mo.group(1))
	return re.sub(r"\$LOG\((.+?)\)",decsub,file.read(),re.MULTILINE)
	
if __name__=='__main__':
	password=None
	decrypt_option=False
	for i in range(len(sys.argv)):
		if(sys.argv[i]=='--password'):
			password=sys.argv[i+1]
		else if(sys.argv[i]=='--decrypt'):
			decrypt=True
		else if(sys.argv[i]=='--encrypt'):
			decrypt==False
	if(not password):
		password=getpass.getpass("Enter password")
		
	if(decrypt_option):
		sys.stdout.write(decrypt(sys.stdin,password))
	else:
		encrypt(sys.stdin,password)