Chapter 9. Jefferson-Patterson Ciphers

Soon after becoming president of the United States, Thomas Jefferson received a imaginative proposal from Robert Patterson for a novel cipher system, one that clearly surpassed the earlier and simpler designs of James Lovell. Patterson, an immigrant to America in 1768 from the north of Ireland, became a schoolmaster near Philadelphia for a short time before returning to that city and continuing his private studies. He established a country store in New Jersey several years before the Revolution, but after a year he closed that establishment and became principal of the Academy in Wilmington, Delaware.

After the outbreak of hostilities with Great Britain, Patterson, who had been a sergeant in a militia company ...

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