John A. Nagy’s recent book “George Washington’s Secret Spy War” claims that the general’s skill as a spymaster acquired during the French and Indian War won the War for Independence. Using Washington’s diary as a primary source, Nagy discovered hundreds of spies who went behind enemy lines to gather intelligence. Although it was a rule of the period that a gentleman did not read private mail, the American commander-in-chief used espionage to level the playing field and exploited its use to win victory over the best trained army of his day.
Although Gen. Washington respected the brave men who went into dangerous places at his request, he did not completely trust them. Because mistakes can be made, Washington preferred agents who had the intelligence and training to use ciphers.
The Pig Pen cipher was used by the Americans, British, French and Hessians. A substitution cipher, it exchanges letters for symbols which are fragments of a grid. Both the sender and receiver must agree on the placement of the letters in the grid. Letters in the grid are identified by the number of dots in the segment. Each letter in the segment is replaced by a segment with the corresponding dots.