Cipher

Cipher is a quote cryptogram on Puzzle Theory, a site of twenty daily word, number and logic puzzles that all reset at 00:00 UTC. Every letter of a famous quote or proverb has been replaced by another letter, and the same swap holds across the whole line. Your job is to find out what each coded letter really stands for.

A new puzzle goes up at 00:00 UTC and is the same for every player. Two letters are filled in for you at the start. Under the coded line sits a row of boxes, one for each coded letter in the quote: type a real letter into a box and it fills in every place that letter appears, so one good guess can open up several words at once. Each real letter can only be used once, and giving it to a new coded letter takes it off the old one. A timer and a count such as 2/14 letters show how far along you are, and the puzzle finishes by itself as soon as every guess matches the quote. A Reveal solution button gives up and shows the answer.

The quotes are short and familiar. In the game's code the Normal daily is drawn by the date from a bank of 35 well-known lines, with a new letter key made for each day, so a regular player will meet a quote again within a few weeks, though in a different code. Hard mode adds 16 longer, less familiar quotes to the mix.

The daily quote and the unlimited practice mode are free and need no sign-up. Puzzle Theory Pro, a paid plan with a 7-day trial, opens the Hard mode, a 30-day archive of past puzzles and synced streaks, and removes ads; the free page loads Google AdSense. A leaderboard for the day sits beside the puzzle.

Cipher suits players who like newspaper cryptograms and want one short quote a day in the browser, with letters rather than numbers as the code.