Question

I am currently thinking of something to do as my final project for my C# class. The thing that came up to my mind was a password-protected data storing application which would require a password to access data stored in a binary file.

The problem is that I am not sure which encryption to use if I would decide to do this project.

What encryption would fit best this scenario? Which encryption is the best?

Just little more info what I have planned.

First, user must specify the user name/password information to save the data. Data would be saved in binary file which later should be able to view after login information are correct.

Answer 1

I think you should go with AES in CTR mode.

A C# implementation of Rijndael (the underlying cipher of AES) can be found here.

There is probably not such a thing as the best encryption algorithm, but it is what everybody else is using right know.

To clarify further:

This is how encryption works:

Plaintext -> [encryption] -> Ciphertext -> [decryption] -> Plaintext

This is what you would have to use for a password manager.

This is how hashing works:

Message -> [hashing] -> Hash -> [???] -> Message

You can (and should) use hashing algorithms to store (hashed) passwords in a database for authentication purposes (e.g. log into a website). To do so, you use a salt or a key-based message authentication code.

Instead of “dehashing” the hash stored in the database, you just hash the user input and verify if it matches. This does not work for an application like a password manager.

With a cryptographically secure hashing function (like SHA-512), it is currently impossible to “dehash”, i.e., even if you know the hash, you cannot retrieve the message.