Did you know?
QR stands for 'quick response'. The QR code was invented in 1994 by Masahiro Hara, an engineer in Japan, to keep track of car parts in factories. Today we scan QR codes to pay, read and learn!
More than 2,000 years ago, the Greek historian Polybius described a way to turn letters into pairs of numbers using a 5 × 5 grid. Messages could even be sent at night by holding up torches!
For centuries, nobody could read Egyptian hieroglyphs (picture writing). The Rosetta Stone, found in 1799, carried the same message in three scripts, including Greek. Using it, Jean-François Champollion cracked the code in 1822!
Try this: Crack the Number Grid
Draw a 5 × 5 grid. Fill it with the alphabet, row by row: A B C D E in row 1, F G H I/J K in row 2 (I and J share a box), and so on. Each letter becomes its row number, then its column number, so B is 12. Decode this word: 43 32 24 31 15.
Show answer
SMILE
Go further: Codes Made of Shapes
The pigpen cipher, also called the noughts-and-crosses cipher, swaps letters for shapes. Draw a noughts-and-crosses grid and write A to I in its nine spaces. Now each letter is written as the lines around its space. E sits in the middle, so it becomes a little square! Make more grids, with dots or X shapes, for the rest of the alphabet. About 300 years ago, a group called the Freemasons used this cipher to keep their records private.