A substitution whose cipher alphabet is spelled out by a keyword: its letters first, then the rest in order.
substitution cipher
easy to break by hand
16th century — today
A classic keyed alphabet, described in early cryptologic manuals; popular with hobbyists ever since.
encrypt · decrypt · cryptanalysis
0 letters, 0 distinct symbols, sorted by frequency.
Compare the bars with English: the tallest cells should be E, T, A, O… Reading the shape first makes every later guess cheaper.
Decrypted so far