TheCodeBreakers
of West Coast rum running vessels." One such system, employing two
different commercial codes, passed through five steps: The clerk (1)
encoded the plaintext in the commercial ABC Code, 6th edition, (2) added
1000 to the numerical codegroup, (3) looked up this codenumber in
another commercial code, the Acme, (4) transcribed the codeword
opposite that codenumber, and (5) enciphered that codeword in a
monoalphabetic substitution. Much of this complexity, however, was
vitiated by the clerk's habit of only partially encoding messages and
enciphering the rest in a monoalphabetic substitution that appears to
have been the same as for the code. Mrs. Friedman illustrated
the process with an actual message (which may have some slight
errors in it):
plaintext Anchored in harbor. Where and when are you sending
fuel?
in ABC Code 07033 52725 24536
+1000 08033 53725 25536
annaabi.ee 
