Zodiac Cipher Cracked

I admit I don’t pay much attention to pencil-and-paper ciphers, so I knew nothing about the Zodiac cipher. Seems it has finally been broken:

The Zodiac Killer was a serial killer who preyed on couples in Northern California in the years between 1968 and 1970. Of his seven confirmed victims, five died. More victims and attacks are suspected.

The killer sent four messages to newspapers in California’s Bay Area, only one of which has ever been decrypted. This first message ­ split into three parts ­ claimed Zodiac wanted to kill victims so that they would become his slaves in the afterlife.

The 408-symbol cryptogram was cracked by Donald and Bettye Harden of Salinas, California.

Code and solution—with photos—here.

EDITED TO ADD (8/5): Solution seems to be a hoax.

Posted on August 5, 2011 at 12:25 PM27 Comments


Paul August 5, 2011 1:07 PM

Fake. First off, it’s Daily Mail (which a lot of Americans seem to trust; it’s weird how often Schneier posts Daily Mail links without providing skepticism).

From the article:

“After completing his work, Mr Starliper tried to reach out to Bay Area authorities to report his findings, but it wasn’t well-received.

After little success contacting Solano, Vallejo, and Napa counties, he tried the San Francisco Cold Case and Special Investigative Units.”

This sounds plausible. Granted, Leigh Allen wasn’t brown, but you’d think any counties touched by Zodiac would kill to publicize solid evidence. That must mean he wasn’t providing his methodology for cracking the code.

In 9 hours he claims to have decoded:


Yeah. Not buying it.

Jeff August 5, 2011 1:10 PM

I was waiting for Schneier to weigh in on this… and I was expecting more skepticism. Did you look closely at how he claims to have decoded it? Seems sketchy at best.

Increasingly Less Anonymous Poster of Brucedom August 5, 2011 2:02 PM

Thank for the link TS. Doubtful that will get as much publicity.

I’ve always wanted to try decrypting Bruce’s plain text posts as if they were encoded to reveal the truth about his involvement with the Cuban Missile Crisis. Now that I know this guy’s technique I can do it.

Frank Ch. Eigler August 5, 2011 2:40 PM

It’s like retroactively creating a “one-time pad” to decrypt a given cyphertext to any desired plaintext.

Paul August 5, 2011 3:05 PM

I found an error in his Caesar Cipher. FTFH:


Richard Steven Hack August 5, 2011 6:58 PM

Paul: As indicated above, it appears the Daily Mail picked up the story from other sites in California. So the story in the Mail isn’t relevant.

As to whether the guy actually did it, I defer to the crypto experts here and elsewhere who are skeptical.

Bruce Schneier August 6, 2011 9:49 AM

“I’m surprised that you posted this.”

As I said, I don’t pay much attention to pencil-and-paper ciphers.

Gabriel August 6, 2011 9:49 PM

@less anon: do you really think Bruce is gonna bother with stuff as trivial as the Cuban missile crisis? How about the Higgs boson which he creates in his sink? Or who truly rules the earth? Or where intelligent life may be found and how to get there. (hint: it involves a chuck Norris kick)

Gabriel August 6, 2011 9:55 PM

Bruce, I am saddened. I was hoping you would be the one to know what the voynich manuscript says. I’m sure Starliper will try to take credit for that.

al August 7, 2011 11:36 PM

personally I would be interested of knowing who really rules the earth since Gabriel now happened to mention it, so if Bruce has any info on that it would be appreciated.


Roger August 9, 2011 8:01 AM

David Oranchak has already posted an excellent rebuttal. A couple of other things to consider:
* The unsolved Zodiac ciphers are one of those things that continuously attract amateurs who are sure they have finally found the solution and won’t hear otherwise. Invariably, the “solution” involves so many degrees of freedom that they can make any message kind-of-sort-of fit.

  • This “solution” includes a confession by suspect Leigh Allen. I wouldn’t expect anyone to realise this unless they have an unhealthy obsession with the Zodiac murders (ahem), but Leigh Allen is to Zodiac as the “Royal Conspiracy” is to Jack the Ripper: a persistently popular theory that proves to be utterly ridiculous once you look into the detailed facts.

Helen-lyn malcolm December 21, 2011 1:50 PM

ive actually cracked what believe to be ciphers 3, 4, and 34o, you can check it out at ghosttheory.com helen-lyn malcolm tell me what you think.

Jourdan February 19, 2012 6:31 PM

Did anyone ever consider that the man who solved it with his wife could have done it. How many people tries and some guy and his wife solved this one and then cant solve the next one? You would think if the same person made these ciphers that the thinking behind it would be similar. So knowing the answer to one would help to possible find the answer to the other.

Helen-lyn malcolm April 21, 2012 11:28 PM

I completed what i thought was the zodiac cipher sometime ago. my results are as follows: cipher 340 Pen dripping cipher
If uv given up il give you another go
il save you something to rember me by
im kpping a vic
r you going to chase me
is the message to diff
what is cut or made for unlucky men
ur running out of bodies
all ul discovr is i no y you can stop and laugh
ceyhi for me
ps is good at many things you would like him alot
cee you around
have a great day
justice or victory
catch me if you can or kill me
im not slowing down youl neva find me julian
yt z

Helen-lyn malcolm April 21, 2012 11:33 PM

once again what i believe to be the ciphers decoded.

Cipher 3
chaseecz was fun
i kill bcuz i can
i am m w
if i hear zodiac has been found i will kill agn
please find z
catch me if you can

cipher 4
if you havent been laughing go c a dr
fmw in park picnic huntn
had a ball

Hope these help.

Les Hubble November 19, 2014 3:18 PM

Reference to the Zodiac “my name is____”. The block style anagram
[ AEN….NAM] has to simply be ANONYMOUS , very common in newspaper columns in newspapers in that period and the characters obsession with newspapers is obvious. I dont see the letter “J” anywhere, but then I haven’t seen most of the cryptograms.

Chad William Burke December 9, 2019 4:30 PM

Via a modified version of Edgar Allen Poe’s split alphabet cipher.

My name is —



the ????


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