Bacon (letter case) — Bacon's biliteral system hidden in the letter case of ordinary prose, so the message looks like innocent text.
Uppercase/lowercase of ordinary text encodes Bacon's five-bit letters.
A worked example§
Encrypting a sample with the cipher itself, at build time:
MEET ME BY THE OLD CLOCK TOWER AT DAWNNo key — the transformation is fixed.
produces the ciphertext
ThE raILwAY STaTIoN At AShForD WaS CROWDed WitH tRAvELLers WAiTINg fOr ThE dELAYed EXPrESs AnD The StATIoN MaSTer WAlKEd uP anD dOWN ThE PlATFORM MUTtERiNG ABouT THE WeAtHER anD TThis example is generated by running the cipher when the page is built, and the round trip is checked, so it always matches what the solver does.
How it is broken§
Steganography rather than cryptography: the detection is the attack. A mixed-case run whose length is a multiple of five is the tell.
History and context§
Bacon's own intent — he cared about concealing that a message exists, which is a different problem from concealing what it says.
See also§
Morse code · Bacon cipher · A1Z26 (numbered alphabet) · Polybius square · Tap code · NATO phonetic alphabet
Browse every cipher in the Codes and alphabets family, read the history of codebreaking, or return to the wiki main page.
Frequently asked questions§
How is the Bacon (letter case) broken?
Steganography rather than cryptography: the detection is the attack. A mixed-case run whose length is a multiple of five is the tell.
What key does the Bacon (letter case) use?
none. There are 2 possible keys.
How much ciphertext do I need?
At least 20 characters for this solver to attempt it; short messages can be readable and still not be proof.
Can I break a Bacon (letter case) on this page?
Not with the browser build, which targets the common puzzle families. The desktop version searches it: see the Windows app page.