Classical and machine ciphers, from Caesar’s shift and the ACA’s 62 types to Enigma and Lorenz, and text as notes: enciphered with a key, chained, many broken without one.
Cipher Chain
Runs a message through steps in turn — 100 of the app’s own: ciphers from Caesar to the ACA’s types, three machines, Base64 and fifteen more encodings, two hiding places, eight text operations — to a coded text the route undoes from its last step back, each step saying what its way back loses. Shannon (1949) called such chains product encipherment, his first example a substitution followed by a transposition.
Terms
About this tool
History
Claude Shannon (1949) calls two ciphers applied in turn their product: the message enciphered by one, the result by the other, the key of the whole both keys; his figure 3 undoes them in the opposite order. He writes (p. 671): “Product encipherment is often used; for example, one follows a substitution by a transposition or a transposition by a Vigenère, or applies a code to the text and enciphers the result by substitution, transposition, fractionation, etc.” The German army’s ADFGVX of 1918 is one. Cipher Chain replaced the Cipher Pipeline in 2026.
How it works
Each step is a cipher, machine, encoding or hiding place of the app’s own, from the module its tool uses: nine ciphers that keep spaces and punctuation; Scytale, Bacon and ADFGVX; 59 of the ACA’s types, by its rules; Enigma, Chaocipher and Solitaire; sixteen encodings; two ways of hiding in a cover text; eight operations on the text. Encoding runs the steps from the first, decoding from the last. After every step the tool decodes what it wrote and names what does not come back: case, punctuation, J read as I, a filler X, letters added to fill a block. The route copies as a key sheet, or as a link to Decode without the message or the cover texts.
How it was checked
The tests run all 100 steps on one sentence with their first keys, the four types whose block must hold the text on a text of that size, and read it back: the ciphers on the whole text, the byte encodings and the hiding places exactly, and every step that loses something but the Seriated Playfair says what; accented letters, and a text without letters, are tried too. Enigma’s AAAAA to BDZGO, Schneier’s SOLITAIRE to KIRAKSFJAN, Rubin’s Chaocipher example and the ACA’s Vigenère sheet pass through the chain; a route of five steps decodes to the message’s letters.
Limits
The ACA’s types write letters only, in fives; those with a square of 25 read J as I. The Cadenus, Route, Grille and Nihilist transposition take only a text their block holds; the Keyphrase and Tridigital give several letters for a sign. Capitals, small letters, trimming, removing spaces and replacing are one way. The M-209, Typex, SIGABA, Purple and Lorenz, whose keys are books of settings, are not steps. The link carries the keys: whoever has it and the coded text reads the message.