E-Book Overview
This book provides an excellent foundation for solving cipher systems. The text describes the fundamental principles of cipher solution plus use of the unilateral frequency distribution in the solution process is covered in some detail. Various unilateral and multilateral systems are carefully discussed. In addition, the text introduces the student to the solution of digraphic substitution ciphers, including the solution of the Playfair Cipher. Numerous problems are provided for solution by the student.
E-Book Content
A CRYPTOGRAPHIC SERIES nAn MILITARY CRYPTANALYSIS PART II With Added PROBLEMS and COMPUTER PROGRAMS Introductory remarks ........................................... Cipher alphabets for polyalphabetic substitution ................ Theory of solution of repeating-key systems ..................... Repeating-key systems Lvith standard cipher alphabets ......... Repeating-key systems with mixed cipher alphabets, I .......... Repeating-key systems with mixed cipher alphabets, IT ......... Theory of indirect symmetry of position in secondary alphabets Application of principles of indirect symmetry of position. ...... Repeating-key systems with mixed cipher alphabets, III ........ Repeating-key systems \vith mixed cipher alphabets, TV ........ Appendix l...................................................... Appendix 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P R O B L E M S . .................................................... COMPUTER PROGRAMS ...................................... Yagm . . . . . . 1-3 . .