Using the SHA-3 to Derive Encryption Keys Based on Key-File

This paper is about a proposal of the algorithm to derive encryption keys based on key-files using the hash algorithm SHA-3. For our upcoming design of block cipher with special key length, which is 111 bytes, we are facing the problem how to derive encryption keys, even there are for example scrypt or Argon2 key-derivation function, we would like to design algorithm specialized for generating hashes of the required length. Thus, we proposed whole new algorithm. We also wanted to forge encryption keys based on key-files and do not limit only for passwords as the source. So, this paper presents the design of the final algorithm and results from testing it. This work is also the first proposal and in the future is planned to test it more.