The first section of this article is a refresher, before we incorporate the rarely mentioned 'American Greetings' card, postmarked December 1990. This card, devoid of any handwriting on the card inner, was the sister communication to the Halloween card, also beginning with "From your secret pal", but contained a photocopy or xerox of two keys that have mystified as to their meaning. We will attempt to combine this communication with the Halloween card and explain its relevance to the Zodiac Killer's unsolved 340 cipher. As always, this analysis must be treated with a healthy dose of skepticism.
So firstly, I would like to press home the notion that the Zodiac Killer's 340 cipher was nothing more than a ruse, designed to stick two fingers up to the challenge laid down by Professor D.C.B. Marsh of the American Cryptogram Association (ACA) on October 22nd 1969, when he "invited Zodiac to send The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name." The Zodiac Killer would eventually reveal the workings of the 340 cipher just over a year later when he mailed the rather cryptic Halloween card on October 27th 1970, revealing the trick, not treat, he had perpetrated on his challengers. The killer couldn't have been any more obvious when he actually wrote "sorry no cipher" on the envelope inner.
So firstly, I would like to press home the notion that the Zodiac Killer's 340 cipher was nothing more than a ruse, designed to stick two fingers up to the challenge laid down by Professor D.C.B. Marsh of the American Cryptogram Association (ACA) on October 22nd 1969, when he "invited Zodiac to send The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name." The Zodiac Killer would eventually reveal the workings of the 340 cipher just over a year later when he mailed the rather cryptic Halloween card on October 27th 1970, revealing the trick, not treat, he had perpetrated on his challengers. The killer couldn't have been any more obvious when he actually wrote "sorry no cipher" on the envelope inner.
In 1970, the Zodiac Killer mailed the Dragon card, the Kathleen Johns letter, the Little List letter and the '13 Hole' postcard, none of which stated the glaringly obvious, that he hadn't sent a cipher with any of them. Why would he then apologize for not sending a cipher with the Halloween card when it was patently apparent upon opening the communication? Even if he had wanted to apologize, why didn't the Zodiac Killer just write "sorry no cipher"? The fact he wrote it twice in the form of two intersecting lines suggests this design was created for a purpose. The only other intersecting text on the entire card were the words "Paradice" and "Slaves", so was the author of the Halloween card telling us that something he had created wasn't a cipher, only the intersecting words of "Paradice" and "Slaves"? If we could find "Paradice" and "Slaves" intersecting each other in any previously unsolved cipher, structured in similar fashion to "sorry no cipher", then this should be a strong argument to the meaning behind the Halloween card. We need to find "Slaves" running horizontally, preferably at the center of the 340 cipher and bisect it with the word "Paradice" (hopefully beginning with the letter "P" somewhere at the top of the cipher along the 9th column).
Fortunately, nine characters along the top row is the letter "P". Then we must travel downwards 17 characters in order to create two lines of equal length and find the "E" of "Paradice". This will now be represented by the character "<". We now have two lines of 17 characters, bisected by a "+" sign (the center of the crosshairs). The 'wings' of the crosshairs are represented by two dashes, situated in columns 1 and 17. These represent the two "S" letters of "Slaves". This is all very convenient.
There are only two identical characters (the "+" sign) in the 9th column along the first 10 rows, and we know the letter "A" is center of the bisecting "Paradice" and "Slaves" on the Halloween card. It is then a simple task of placing the "R" of "Paradice" and "LV" of "Slaves" into position, to exactly mirror the Halloween card formation. It is then not difficult to find the word "By" in all four quadrants of the 340 cipher, again mirroring the Halloween card. See here for visual.
The second clue may have also come from the envelope, when the Zodiac Killer underlined the 'LAV' of the misspelled Paul Avery on the address side. The three letters 'LAV' bisected the center point of the 340 cipher. What are the odds of "sorry no cipher" mimicking the "Paradice" and "Slaves" formation on the Halloween card, which then mimicked the 340 cipher, along with the three alphabetical letters 'LAV' being integral to both.
There are only two identical characters (the "+" sign) in the 9th column along the first 10 rows, and we know the letter "A" is center of the bisecting "Paradice" and "Slaves" on the Halloween card. It is then a simple task of placing the "R" of "Paradice" and "LV" of "Slaves" into position, to exactly mirror the Halloween card formation. It is then not difficult to find the word "By" in all four quadrants of the 340 cipher, again mirroring the Halloween card. See here for visual.
The second clue may have also come from the envelope, when the Zodiac Killer underlined the 'LAV' of the misspelled Paul Avery on the address side. The three letters 'LAV' bisected the center point of the 340 cipher. What are the odds of "sorry no cipher" mimicking the "Paradice" and "Slaves" formation on the Halloween card, which then mimicked the 340 cipher, along with the three alphabetical letters 'LAV' being integral to both.
The Zodiac Killer knew that the first anniversary of his 340 cipher being unsolved was fast approaching, and this Halloween opportunity of revealing his trick to the world, albeit wrapped in another cryptic message, was simply too much to resist.
The words "Paradice" and "Slaves" were decoded in the 408 cipher and featured prominently in the Halloween card, so what are the chances they were an integral part in the design of the 340 cipher as well? So much so, they may have formed crosshairs, bisecting the cipher at its midpoint? If none of the above was an intentional creation by Zodiac and it all fell out by accident, then he is certainly one hell of a fortunate designer.
In the words of Thomas Horan, the 340 cipher was certainly the "Great Zodiac Killer Hoax of 1969".
When the Zodiac Killer mailed his trinity of July 31st 1969 communications he withheld his identity or pseudonym, but beginning on August 4th 1969 with his 'Debut of Zodiac' letter through to his March 13th 1971 'Los Angeles' letter, every single letter the Zodiac Killer mailed began with "This is the Zodiac Speaking" (excluding cards). So why should the 340 cipher message be any different - which was effectively a letter within a card.
The words "Paradice" and "Slaves" were decoded in the 408 cipher and featured prominently in the Halloween card, so what are the chances they were an integral part in the design of the 340 cipher as well? So much so, they may have formed crosshairs, bisecting the cipher at its midpoint? If none of the above was an intentional creation by Zodiac and it all fell out by accident, then he is certainly one hell of a fortunate designer.
In the words of Thomas Horan, the 340 cipher was certainly the "Great Zodiac Killer Hoax of 1969".
When the Zodiac Killer mailed his trinity of July 31st 1969 communications he withheld his identity or pseudonym, but beginning on August 4th 1969 with his 'Debut of Zodiac' letter through to his March 13th 1971 'Los Angeles' letter, every single letter the Zodiac Killer mailed began with "This is the Zodiac Speaking" (excluding cards). So why should the 340 cipher message be any different - which was effectively a letter within a card.
We do not know if the Zodiac Killer was responsible for the mailing of the 'American Greetings' card, but for the purpose of this argument we will assume that he was. On the left is the photocopy of the two keys that arrived with the communication. The two keys must have had some meaning to the sender - but what? It is clear that the sender could have photographed the keys, drawn two keys or even pasted two 'newspaper keys' onto the card, but made the deliberate choice of photocopying two keys for a reason. The act of the photocopying, one would like to believe, was done to convey a message.
A negative photocopy inverts the colors of the document when creating a photocopy, resulting in letters that appear white on a black background instead of black on a white background. Negative photocopies of old or faded documents sometimes produce documents which have better focus and are easier to read and study. Wikipedia. To invert something is to put upside down or in the opposite position, order, or arrangement. Synonyms of invert, are to turn upside down, upturn, upend, turn around, turn about, turn inside out, turn back to front, reverse, flip (over) or transpose. Therefore, was the designer of the 'American Greetings' card hinting that we should "invert the key" or "flip the key". In other words, the key to the 340 cipher is to "invert" or "flip" it on its head in order to read it. The "sorry no cipher" arrangement on the Halloween card envelope was equated with "Paradice" and "Slaves", but could have been written with the 'vertical' "sorry no cipher" running downwards. Could this imply that "Paradice" was meant to be flipped on the 340 cipher, running from bottom to top?
A negative photocopy inverts the colors of the document when creating a photocopy, resulting in letters that appear white on a black background instead of black on a white background. Negative photocopies of old or faded documents sometimes produce documents which have better focus and are easier to read and study. Wikipedia. To invert something is to put upside down or in the opposite position, order, or arrangement. Synonyms of invert, are to turn upside down, upturn, upend, turn around, turn about, turn inside out, turn back to front, reverse, flip (over) or transpose. Therefore, was the designer of the 'American Greetings' card hinting that we should "invert the key" or "flip the key". In other words, the key to the 340 cipher is to "invert" or "flip" it on its head in order to read it. The "sorry no cipher" arrangement on the Halloween card envelope was equated with "Paradice" and "Slaves", but could have been written with the 'vertical' "sorry no cipher" running downwards. Could this imply that "Paradice" was meant to be flipped on the 340 cipher, running from bottom to top?
If we go to David Oranchak's excellent Zodiac Killer Ciphers website and employ his 340 cipher Webtoy using the 'flip vertically' function, the 20th and 1st rows are flipped, the 19th and 2nd rows are flipped, and so forth. In essence, the bottom line now becomes the top line. The "Zodiac" he gave us on the 20th line is now in the perfect position on the top line to open up this communication or cipher with the infamous words "This is the Zodiac Speaking", just like every other letter from August 1969 to March 1971.
The correspondence before the Halloween card was the October 5th 1970 '13 Hole' postcard. It too contained a cross and flipped text, stating "There are reports city police pig cops are closeing in on me. Fk I'm crackproof. What is the price tag now?"
Wouldn't it be nice if "Fk" meant "Flipped key" as well, and the '13 Hole' postcard was the third member of the trinity of solutions to the Zodiac Killer's unbreakable 340 cipher.
The correspondence before the Halloween card was the October 5th 1970 '13 Hole' postcard. It too contained a cross and flipped text, stating "There are reports city police pig cops are closeing in on me. Fk I'm crackproof. What is the price tag now?"
Wouldn't it be nice if "Fk" meant "Flipped key" as well, and the '13 Hole' postcard was the third member of the trinity of solutions to the Zodiac Killer's unbreakable 340 cipher.