Zodiac Killer's 340 Cipher Cracked Now!

















































        ... Or call it a "significant progress towards the solution". I have partly deciphered the unsolved Zodiac-340 cipher which is supposed to be composed by the Zodiac Killer over 40 years ago. The cracked part reveals a name.


Listed below are the steps I have taken to (partly) decipher the Zodiac 340 message:


Step 1 : Using “Zodiac” as Entry Point


Matching that part with “ZODIAC” seems almost automatic.


Step 2 : Guessing the “Amazing”/”Amuzing” and “Ignoring”/”Ignorant” Parts


After Step1, part of Lines 2-3 becomes :


   Put the word “amazing” or “amuzing” into Line#3. Since W becomes N, this will also fit into Line#2, yielding a reasonable end word such as “iGnOriNg” or “iGnOraNt”. Some other word like “bOriNg” would be unlikely for that part, since this would produce the odd ending : --M-G BORING. Plus, remember that the letter which was sent along with the cipher contained a clue about being ignored : “When I am ignored....”

    We cannot be sure whether it should be “iGnOriNg” or “iGnOraNt”, nevertheless we can place the letters I, N, R safely, in either case.

    Recalling Zodiac's misspellings in Zodiac-408 cipher, we'd better keep in mind that “amuzing” could be also possible instead of “amazing”. Thus for this part we have so far:


Step 3 : “Going” Part


After Step2, part of last two lines becomes :


    The OI part suggests something like “doing”, “going”, or “into it..” . “doing” seems unlikely since Y=D is also a part of “Ignoring”/”Ignorant” (Step 2). So Y should be either G or T. I went with G, since “going” and “ignoring” seemed more common than “into it” and “ignorant”.


Step 4 : “Uncle”

Revisiting Line 2-3 we have :


Let's concentrate on -NC--I--- AM-ZING part.

It should be “Uncle”. “Including”, “Encri..”, “Encou...”, etc. are not possible.

“Encoding” is a candidate, but then there will a single letter between “encoding” and “amuzing”, plus this is not as common as “uncle”. So is it “uncle is so am-zing” ? I put “Uncle is so amuzing” there.


Step 5 : “Going” => “Is going to” and “Posting” Parts


Revisiting the “going” part (Step 3) :

I made a guess about it that it could be “is going to”.

Now, look at line above. There are obvious hints that it is “posting”. The cipher was “post”ed along with a letter.


Step 6 : The big U-Turn now : M is becoming S !!


It's time to see the picture as a whole now:

















   Concentrate on the last sentence, starting from the word “posting”: “Posting....nu... is going to... Zodiac .m”

  If this is a grammatically correct English phrase, it likely should end as “Zodiac iS” rather than “Zodiac I'm”. I figured out that it is something like “... Posting it and no one is going to sai (say) who Zodiac is”.


I dared a try, so the last letter (M) became S.

The text is getting a latin/spanish character.


Step 7 : “Disgust”


After M->S conversion it appeared FISGUSR in the text. F=D and R=T makes it DISGUST.

The F->D conversion fits to SPIF -> SPID and


parts. (Becoming something like “DiagnoseD” after the conversion)


Step 8 : Back to “Uncle” - What does he do?








Uncle is so asuzing el ... Uncle issoas uzing elnites?

“elnites” could be an anagram for “lentis” (latin word for “lens”)

(The text has an intense Latin/Spanish character) .

I also thought that the Zodiac sign could mean “I”

And it fits the following to become “ISOLA” (island) :


Ok. Uncle is uzing lentis... and?








Sqq ? Seet (seat) sad ... eets (eats) adn(and)


Notice that those guesses also fit that short sentence, making it “... goes” :

Step 9 : After applying the changes in Step8 now we have a name!











I was shocked when I noticed for the first time that there is a name appearing: Daniel Sentino.

I had never dealt with that part, so could that name appear by chance??? 


“Daniel Sentino posting eead (it) ... (a) nut is going to sai (say) thees I Zodiac is” !


This name (Daniel Sentino) fits to the following pattern by length (Zodiac's "My Name is..." cipher)


















Step 10 : Is it possible to go far?


Maybe yes. I guess the part before Daniel Sentino might be “La tinto Islantus”

Tinto is “red” and “islantus” could be the fish , the cichlid species (cichlasoma istlanum)



























The most important thing is whether it says that “A NUT” is going to say... or “DOANUTL” (Donald) is going to say it. Donald was the solver of the first cipher as you know.





  • This is a playful message written in “bad English”, mixed with several words borrowed from languages of Latin origin (Latin, spanish, italian, etc.). So it has a very different tone of voice than Zodiac 408. Remember what Zodiac (?) wrote in the letter he sent along with that cipher: "I thought you would need a good laugh".
  • No mention of slaves or afterlife. The verb “kill” was never used. The pi symbol is missing this time.
  • The first line looks as if it is saying “pleeeaseeee ignoring”
  • Los Angeles appears at line #8, and "study" or "studio" at line #10.
  • The name is either Daniel Sentino , or Daniel Mentino (less possibility).
  • Zodiac-340 cipher is also a monoalphabetic substitution cipher, but with the difference that the Zodiac-340 ciphertext does not map to a meaningful plaintext as a whole. That is to say, there is a unique meaningful part in the message, and all other parts can be ignored once you have uncovered this important part which contains the “real” message. This is why all cracking efforts failed so far – people were after a completely meaningful message, word by word, letter by letter, as it was the case with Zodiac-408 before. Since Zodiac-340 cipher is not of that character, they went wrong.






You will need my written permission to copy & publish this solution on any communication medium.


This is the first publication of this solution of the 340 cipher (on 4th October 2012). 


4th October 2012



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Comments (2)

  1. josephcovinojr

    This new crime suspense thriller novel advances fresh new heretofore un-investigated plausible LEADSin this case, check it out:

    April 29, 2013
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  4. winniesloan

    The bottom line, reading right to left, says, “It’s Zodiak speaking”

    March 04, 2014
  5. alien666

    Yep. If you read the words from the end to the begin, says ““It’s Zodiak speaking, sending a post in Latin”.

    Is there someone who knows Latin?

    February 23, 2017