There are many unanswered questions surrounding the Zodiac Killer. He was never caught, and the 340-word cipher which he sent to the San Francisco Chronicle has never been cracked. Until this week, when a Massachusetts man named Corey Starliper claimed to have cracked the code and revealed Zodiac's true identity.
There are several reasons why a cryptogram might never be solved. Unfortunately it isn't true that, as Starliper is quoted in the local newspaper, "Any code created by man can be cracked by man." For example, it has been widely tested and verified that messages encrypted by one-time pads cannot be cracked (barring a scenario where the one-time pad is not thoroughly destroyed after use, which is how these things often go).
It is also true that 340 random letters cannot be cracked. Might the Zodiac Killer have deliberately sent a block of gibberish to the newspaper, in order to vex investigators? His first few missives were trivially cracked by random amateur public sleuths (after they were published in the newspaper). This certainly would have stung the man's ego.
As much as we might want the mystery to finally have been solved, Starliper's work has been pretty thoroughly torn apart online. Problems identified so far include:
- Starliper begins with the observation that 340 is the area code for the U.S. Virgin Islands. However, this number wasn't assigned to the USVI until 1997.
- The substitution cipher changes frequently - sometimes as often as every letter. Seemingly at random. Using this metric, you can make anything say anything.
- Starliper's work has been sent to a professional cryptographer who reviewed it and declared it "not valid."
- Starliper began by changing the non-alphabetical symbols (like < and > ) into what he perceived as being their nearest alphabetical counterparts. This flies in the face of cryptography convention, to say the least.
- Starliper's decrypt also brings no new information to the table, and isn't nearly as nutty as the other confirmed Zodiac letters (in which he explains that, for example, he is killing people to use their souls as slaves in the afterlife).
- It points blame on Arthur Leigh Allen, who was the only prime suspect during the initial investigation. However, only circumstantial evidence has ever been provided for Allen's guilt. And a 2007 DNA test on the saliva used to close one of the Zodiac Killer's envelopes tested out as not matching that of Arthur Leigh Allen.