It is believed that in part, largely to the prompting of the Clinton Administration to declassify across the board older classified documents - in general those over fifty years old- regardless of their degree of classification or sensitivity, the National Security Agency has now declassified some five-thousand highly sensitive documents which can now be found in the National Archives. A listing with title of these released documents can be found in book C-83, NSA CRYPTOLOGIC DOCUMENTS also by Aegean Park Press.
The present book C-89, NSA REVEALS HOW THE CODES OF MEXICO WERE BROKEN, describes the techniques used in "breaking" the Mexican cryptographic systems. The solutions of the systems, MXC, MXD, MXE, and MXH, as titled by NSA, are described in detail. The systems include transposition, substitution, and combination transposition-substitution systems. In addition, the National Security Agency has kindly provided dozens of raw traffic which the reader or student can attempt to solve.
The reader will surely wonder why the U.S. Government has permitted the release of the material found in this book. The dictum that gentlemen do not read the mail of other gentlemen has now been proven to be false.
