I made an account on Ether blockchain client long time ago and I lost my passphrase (actually it consists of two words which I probably know (not sure) and some additional numbers among this words that I forgot). But I have a keystore-file (UTC) and I know the external wallet adress (etherscan shows that ballance doesn't changed for 1200 days, which is good). How can I to recover my account? Maybe to brute force combinations offline, how can I do it?
I have some light knowledge in cryptography and can write a program in C/C++, maybe Python. But I don't know how to use data from UTC file and don't understand it's structure. It would be acceptable to make a program, and run it on the processor for a weeks.