American Encryption History – Word Encryption
We’ve Come a Long Way
American Word Encryption – Advances in cryptography make today’s encrypted portals nearly impossible to access by outsiders. But let’s look at where we started.
Cryptography in the form of codes, ciphers, invisible ink, and hidden messages was used as a form of data encryption by both sides during the Revolutionary war, including many Loyalists who spied for Britain.
Shortly after the first battle in Concord, New Hampshire, Benjamin Thompson learned of the Colonist’s military plans from leaders who were unaware of his loyalist inclinations. Thompson secretly relayed this information to the British in Boston using invisible ink.
Invisible Ink
Thompson created his invisible ink using gallotannic acid which could then be reactivated by the British using ferrous sulfate. He coupled his secret invisible ink messages with an ordinary message written in plain readable ink. Typically, the cover message revolved around commerce; such as requesting a package delivery or asking for a copy of a receipt. This way, if the message was ever intercepted by the American rebels, they would not be suspicious to question an apparently blank piece of paper.
Thompson’s cover method was far from perfect. The visible portion took barely half a page, and yet, there were three pages enclosed in the letter, so it was still somewhat suspicious. The real content of Thompson’s message detailed how many men the Colonists hoped to raise, that their first movement would be against Boston, and their plans to appeal to the French and other European powers for assistance.
Part-Time Spy
Eventually, Thompson went from being a part-time spy to leaving his wife at the outbreak of the war to serve General Gage as a colonel and continue espionage. Not all of General Gage’s spies fared so well and Dr. Benjamin Church is one example.
Dr. Church was one Gage’s most highly placed spies. He was a member of the Sons of Liberty and the Committees of Correspondence. Additionally, he was elected as a delegate to the Massachusetts Provisional Congress and a liaison to the Continental Congress. In fact, Washington himself appointed Dr. Church as the Chief Physician of the Continental Army – all the while he was a spy for the British.
In August of 1775, Godfrey Wenwood, a Rhode Island baker was approached by his former mistress requesting he connect her with some British officers so she could pass along a letter to them. Wenwood was suspicious, so he convinced her to leave the letter with him to pass on himself. Instead of delivering the letter, he gave it to a friend who opened it to discover cryptic writing of Greek characters, symbols, numbers, and letters, similar to how encrypted file storage makes your documents unreadable to outsiders.
Unable to understand it, the friend gave the encrypted letter back to Wenwood who then presented the letter to George Washington in September 1775.
Enter George Washington
Washington had the woman interrogated and eventually, she admitted the letter came from Dr. Church. Washington and his fellow patriots were stunned because Dr. Church was a highly valued and trusted man in his army. Dr. Church was called before Washington to explain himself.
Church admitted to writing the letter but claimed it was intended for his brother and consisted of trivial matters. In reality, the letter was addressed to Major Cane of the British military. Church refused to decrypt the letter and prove his innocence.
Washington requested two independent decryptions of the letter. The first was done by Dr. Samuel West and the other by a team of men. Everyone enlisted arrived at the same result.
The cipher used a simple mono-alphabetic substitution. Every letter of the alphabet is replaced by a different character, letter, or number. In this letter, for example, Church used a number to represent the letter A, a lower case p replaced E and the Greek letter Theta (Θ) was an R for example.
Mono-alphabetic ciphers are fairly easy to solve because the same letter is always replaced with the same cipher character. It is surmised that Church believed the common misconception that the use of non-alphabetic characters makes a substitution system more secure. History shows otherwise as Washington decryptors solved the message in less than two days. Decrypting the cipher revealed that the Church was providing General Gage with information on revolutionary ammunition, rations, and recruiting, as well as troop strength in Philadelphia and the general mood of the Continental Congress.
The Conviction
When confronted about the letter, Church claimed he was trying to deter the British by showing how strong the American forces were. No one bought into Church’s claims and this one encrypted letter was enough to convict him.
Church was jailed and later offered his freedom as part of a prisoner exchange. The British refused the proposed exchange, so he was exiled to the West Indies in 1780. En route to the islands, the ship carrying Church sank, and he was never heard from again.
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