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2. How to Share a Secret;Shamir;Communications of the ACM,1979
3. G.R. Blakley, Security Proofs for Information Protection Systems, 1981 IEEE-CS Workshop on Security and Privacy.
4. Helen M. Wood, The Use of Passwords for Controlled Access to Computer Resources, National Bureau of Standards Special Publication 500-9.
5. National Bureau of Standards, Passwords Usage, Proposed Federal Information Processing standard.