rotating key cipher
nounUK /rəʊˈteɪtɪŋ kiː ˈsaɪfə/
US /ˈroʊteɪtɪŋ kiː ˈsaɪfər/
A secret code where the key changes each time you use it.
The spy used a rotating key cipher so that even if one message was cracked, the next would still be safe.
OTHER MEANINGS
2. A cipher in which the alphabet is shifted by a different amount for each letter or block.
The rotating key cipher shifted each letter by a new number taken from a secret list.
3. A method of encoding messages where the decoding key is updated after every use.
Each transmission used a rotating key cipher, so the key had to be replaced before the next call.
4. A puzzle technique where the substitution pattern turns or advances as you go.
The puzzle used a rotating key cipher, making the letters harder to guess as the message went on.