Did the founding fathers really use invisible ink ink and other codes and ciphers?

Yes, the Founding Fathers did use invisible ink and various codes and ciphers during the American Revolutionary War. They utilized these methods for secure communication to prevent British forces from intercepting sensitive information. Notably, figures like George Washington and Benjamin Franklin employed invisible ink made from substances like lemon juice, and Franklin also developed a simple substitution cipher. These techniques were crucial for espionage and maintaining secrecy in their correspondence.