double-alphabet cipher
nounUK /ˈdʌbəl ˈælfəbet ˈsaɪfə/
US /ˈdʌbəl ˈælfəbɛt ˈsaɪfər/
A secret code that uses two alphabets to hide a message.
The spy wrote the note in a double-alphabet cipher so no one could read it.
OTHER MEANINGS
2. A cipher that pairs each letter of the plaintext alphabet with a letter from a second, shifted alphabet.
The double-alphabet cipher shifted every letter by three places in the second row.
3. A coding method where two separate alphabets are used for encoding and decoding.
She kept one alphabet for writing and another for reading the double-alphabet cipher.
4. A classical encryption scheme involving two alphabet rows to confuse eavesdroppers.
Historians found a double-alphabet cipher hidden in the old diary.