Intellectual Property Law

Zodiac Killer?s ?Unmasking? Lacks Cryptographic Proof

By Kevin Poulsen

The Southern California women who claimed Wednesday that her deceased father was the famed Zodiac killer says she can prove it in part by providing the secret key to the murderer’s encrypted messages — with one rather serious caveat.

San Francisco was abuzz this morning with Deborah Perez’s claim that she was present as a 7-year-old girl during at least one of the string of seven confirmed murders that paralyzed San Francisco in the late 1960s.

But Perez’s 20 minute press conference turned out to be sadly devoid of solid evidence of her claims. Perez says she wrote some of the letters the Zodiac killer sent out decades ago, a claim her attorney, Kevin McLean, says is supported by a handwriting expert. She also claims she has the eye glasses the killer took from one of his victims — cab driver Paul Stine — and McLean hopes police can recover DNA evidence from the glasses, or at least match the prescription to Stine.

Perez says she realized her father was behind the famous unsolved killings when she saw a composite sketch of the Zodiac killers on an episode of America’s Most Wanted in 2007, though she did not offer reporters a photo of her father for comparison.

That left the cryptographic claim as the most promising — something that could be easily and decisively verified.

The Zodiac killer sent two coded messages to Bay Area newspapers in 1969. One of them — a 408 character cryptogram — was quickly cracked by a high school teacher. The other, a 340 character message, has never been convincingly solved.

“There are letters that were sent that were in cryptic code,” McLean teased at the press conference. “Debra has been able to decipher some of those codes, because it was a code between she and her father.”

If Perez can decypher the 340 character message — which has defied cryptanalysis for decades — that would be incredibly strong evidence of her claim. Perez declined at the press conference to elaborate on the secret code.

So Threat Level reached her and her lawyer by phone later. And it turns out she can only decypher the code that was already publicly decyphered decades ago.

“My dad didn’t give me one of the codes, which is that 340 cipher,” she said.

“He didn’t give her the key but she knows how it works,” added McLean.

The jury is still out on Perez’s other evidence. But Threat Level suspects that the Zodiac killer’s real identity remains a mystery.

Full post as published by Threat Level on April 29, 2009 (boomark / email).