Cipherday #80 · September 11, 2026

The answer to Cipherday #80

The full three-cipher chain from September 11, 2026, the public-domain quote it hid, and how each cipher worked. Today’s chain stays sealed until it becomes a past day.

The revealed quote

“A stitch in time saves nine.”— traditional proverb

Small repairs made early spare you a far larger mending later on.

The cipher chain

1. Stage 1 · Caesar · Shift of 18

   Ciphertext

   Lsdc vgwk fgl uggc jauw.

   Decodes to

   Talk does not cook rice.

   Every letter was slid 18 places down the alphabet; sliding it back the same amount restores the line.

2. Stage 2 · Substitution · Keyword “COMPASS”

   Ciphertext

   C dkura pevepap cbcejrt etrahs mcjjkt rtcjp.

   Decodes to

   A house divided against itself cannot stand.

   A keyword scrambled the alphabet into a fixed cipher alphabet, so each letter always stands for the same partner — letter frequency gives it away.

3. Stage 3 · Vigenère · Keyword “SPHINX”

   Ciphertext

   S haqgzz xu bvjw hhdrp fxum.

   Decodes to

   A stitch in time saves nine.

   A repeating keyword shifted each letter by a different amount, which is what lets one letter encrypt two ways; the right keyword resolves it.