I recently learned about diceware and was thinking about how it could possibly be used to create a one time password scheme. I'm thinking S/KEY is probably more appropriate, but would a system that does this be considered secure?
- Use a strong random number generator to create an initial seed
- Generate a new random number from a CSPRNG
- Create a diceware password from the lower 15 bits (for 5 dice, 18 for 6 dice, etc)
- Store the seed securely
Generating lists of passwords can obviously be done provided you have the starting seed, and you can always generate new passwords by changing the initial seed. Seems simple enough, and diceware's wordlist is > 3 times the size of S/KEY's which seems to make it more secure... However, such a simple scheme seems likely to be insecure due to something I'm missing. Has this scheme been studied before? Is it viable?
Edit: I realized my step 3 is flawed. We need multiple random numbers to extract 15 bits for each word output from diceware. In other words, we need 60 bits for 5 words, and 120 bits for 8 words. But, the point remains the same.