November 1979 - Vol. 22 No. 11
Features
A psychology of learning BASIC
This paper addresses the question: What does a person know following learning of BASIC programming? Several underlying conceptual structures are identified: (1) a…
Password security: a case history
This paper describes the history of the design of the password security scheme on a remotely accessed time-sharing system. The present design was the result of countering…
Breaking substitution ciphers using a relaxation algorithm
Substitution ciphers are codes in which each letter of the alphabet has one fixed substitute, and the word divisions do not change. In this paper the problem of breaking…
The problem of storing and searching large sparse tables is ubiquitous in computer science. The standard technique for storing such tables is hashing, but hashing has…
In this paper we show how to divide data D into n pieces in such a way that D is easily reconstructable from any k pieces, but even complete knowledge of k - 1 pieces…