The Playfair cipher was invented in 1854 by an English scientist and inventor of many scientific breakthroughs of what era?
Playfair cipher The Playfair cipher or Playfair square or Wheatstone-Playfair cipher or Wheatstone cipher is a manual symmetric encryption technique and was the first literal digram substitution cipher. The scheme was invented in 1854 by Charles Wheatstone, but bears the name of Lord Playfair who promoted the use of the cipher.
John Wallis John Wallis ( ; 3 December 1616 – 8 November 1703) was an English mathematician who is given partial credit for the development of infinitesimal calculus. Between 1643 and 1689 he served as chief cryptographer for Parliament and, later, the royal court. He is credited with introducing the symbol ∞ for infinity. He similarly used 1/∞ for an infinitesimal.