All rights reserved

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CRYPTANALYSIS OF SIGABA

A Project Report

Presented to

The Faculty of the Department of Computer Science

San Jose State University

In Partial Fulfillment

Of the Requirements for the Degree

Master of Computer Science

By

Wing On Chan

May 2007

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© 2007

Wing On Chan

ALL RIGHTS RESERVED

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APPROVED FOR THE DEPARTMENT OF COMPUTER SCIENCE

Dr. Mark Stamp

Dr. John Avila

Dr. Robert Chun

APPROVED FOR THE UNIVERSITY

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ABSTRACT

CRYPTANALYSIS OF SIGABA

by Wing On Chan

SIGABA is a World War II cipher machine used by the United States. Both the 

United States Army and the United States Navy used it for tactical communication. In this 

paper, we consider an attack on SIGABA using the largest practical keyspace for the 

machine. This attack will highlight the strengths and weaknesses of the machine, as well as 

provide an insight into the strength of the security provided by the cipher.

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