Hi, I thought about a quite basic cipher based on sha256. It seems very simple but it’s more an example to be sure I understood how it works:
1. I want to cipher a message of length N bits (N % 256 = 0)
2. Define a password
3. Sha256 the password, it gives one hash
4. Continue to apply sha256 on the previous hash, until you can produce an N bits sequence by concatenating all hashes
5. Apply OTP between the message and the sequence of hashes
I guess it has already been proposed and it would probably not be very efficient, but would this be considered as a robust method for the average user? I didn’t include things like preserving the original length of the message etc.