Question

A hash chain is the successive application of a cryptographic

hash function to a piece of data. Describe how does the one-way
hash chain builds a secret critical one-time password system.

Answer 1

A hash chain can be used to generate a series of unique passwords in a one-time password system. Each password in the chain is used only once, providing a high level of security.

Step-by-step explanation:

A hash chain is a sequence of hash functions applied successively to a piece of data. In the context of a one-time password (OTP) system, a hash chain can be used to generate a series of unique passwords that change with each use.

Here's how it works: the initial password is hashed to produce a new password, which is then hashed again to generate the next password in the chain, and so on. Each password in the chain is used only once, and the user usually starts at a specific position in the chain.

When a user wants to authenticate, they provide the current password in the chain. The system verifies the password by hashing it and checking if it matches the stored password for that position. If a match is found, the user is authenticated and the system generates and stores the next password in the chain for future use.