Code Breaking in Law Enforcement

There are some very interesting back issues at the FBI Forensic Science Communications webpage. Volume 8 number 2 issue talks about the long history of code breaking in law enforcement. Criminals have always tried to hide incriminating documents and secure their communications. Some of them were smart and used cryptography to protect information. Unfortunately for them, law enforcement has codebreakers, and they are mostly smarter than the bad guys.

Theodore Kaczynski, the Unabomber, kept log books of his crimes and plans of crimes, yet to commit. After his arrest FBI found these note books and succeeded in deciphering the incriminating writing. Two leaders of the Aryan Brotherhood prison gang were convicted for murder inside the jail, after experts broke their encrypted execution orders. During the prohibition years, rum-runners used encrypted radio communications on a large scale. Among the codebreaker in the battle against the the rum-runners was the legendary Elizebeth Friedman.

But the FBI wasn't always successful. In 1953, an encrypted text on microfilm was discovered in a hollow nickel. The code, called VIC cipher remained unbroken for four years, until a defected spy revealed information on Soviet cipher codes. See the Vic Cipher and hollow nickel case. The Zodiac killer published several ciphers, of which some were never broken. He never got caught.