Another interesting idea would be to encode and commemerate the discovery of cosmic bursts by the CIA's Vela satellites. This spectrum analysis intelligence had to be "decoded". It fits with the artists theme of decoding the mysteries of the universe. The Kryptos insricption might relate to the analysis or raw data reports from the Vela sattellites.

The CIA Discovers Gamma Rays from Outer Space! - In 1967, during the Johnson Administration, the United States entered a treaty that banned the testing of nuclear weapons in space. In order to verify that the terms of the treaty were being observed, in the late 1960s the CIA and other intelligence agencies arranged for the Air Force to launch the VELA series of surveillance satellites, which carried omni-directional detectors sensitive to pulses of gamma rays that would have been emitted in great numbers by any space-based tests of nuclear weapons. The VELA satellites never detected a nuclear explosion, or at least never detected one originating in our Solar System.

However, from the time when the first VELA probe was activated bursts of gamma rays were detected every few days. The intelligence analysts were baffled and suspected satellite malfunctions or some form of deliberate jamming that would hide real tests. Finally, with several satellites in orbit simultaneously it became possible to use the arrival time of the pulses at different locations to determine the direction of the source of the radiation. It was found that the bursts came from a number of directions outside the solar system. The existence of these bursts was kept as a closely guarded secret for several years. Finally, in 1973, a paper was published in Astrophysics Journal Letters describing the observation of gamma ray bursts, and the astrophysicists of the world were confronted with a new phenomenon, which, at the time of the 17th Texas Symposium of Relativistic Astrophysics has still not been adequately explained.

I swear to you that if you do this work properly, you will one day have a river of flowing gold" - Zozimus (Alexandria 3rd century AD).

Appropriate motto. About the right number of characters. From the right time period. It is the instructions (or more of an admonition) on the correct way to construct the Philosophers's Stone. However it's probably wrong. But that's what I would have encoded on the Kryptos.

I wonder if artist James Sanborn has spoofed the CIA by getting them to put a statue on their property which actually refers to their experiments with LSD as a "Philosopher's Stone" that could divine truth.

Here's a paragraph from an article I found on the subject at
http://www.totse.com/en/politics/central_intelligence_agency/ciacid.html

"The whole concept of a truth drug was a bit farfetched to begin with. It presupposed that there was a way to chemically bypass the mind's censor and turn the psyche inside out, unleashing a profusion of buried secrets, and that surely some approximation of "truth" would emerge amidst all the personal debris. In this respect the CIA's quest resembled a skewed version of a familiar mythological theme from which such images as the Philosopher's Stone and the Fountain of Youth derive -- that through touching or ingesting something one can acquire wisdom, immortality, or eternal peace. It is more than a bit ironic that the biblical inscription on the marble wall of the main lobby at CIA headquarters in Langley, Virginia, reads, "And ye shall know the Truth and the Truth shall set you free".

Archimedes ran through the streets of Syracuse naked. Artists like the "naked truth". Archimedes was working on a "crown of gold". He was trying to separate the base metal from the gold. What is true from what is not.

That's what the CIA is supposed to do.

There are many ways to disguse a message, but an artist is restricted by the fact that there are only so many messages worth encoding in a legacy work.

Parts of the Rosetta stone translation refer to gold crowns of Ptolemy. "with them. And in order to make this new shrine to be easily distinguishable [both at the present day, and in future times, they shall set] upon this shrine [ten royal double crowns, made of gold and upon [each of the double crowns there shall be placed the [serpent which it is right and proper to make for the [double crown of gold], instead of the two Uraei"

The rosetta Stone translated into a proclamation about recsinding certain taxes by Ptolemy V.

?OBKRUOXOG HULBSOLIF BBWFLRVQQ PRNGKSSO TWTQSJQ SSEKZZWAT JKLUDIAWI NFBNYP VTTMZFP KWGDKZXTJC DIGKUHUAUEKCAR

The word "Eureka" can be found in the last part of the cipher if the letters are rearranged.

DIGKUHUAUEKCAR

"UEKCAR" rearrange the letters and drop the "C" to get "Eureka". The Rosetta stone was in Greek, Coptic and another dead language of hieroglyphs. King Tut, Carter et al, dealt with death. Archimedes worked for the Ptolomys.

Maybe its something like, "Nothing is certain but death and taxes"

But some words are in Greek, some in Coptic, or maybe even French.

The sculpture looks like the Rosetta Stone in form and mass.

I think the final undeciphered part of Kryptos will be a passage from the Rosetta Stone. I base this on the pyschological vibes I get from the artist. I think if you put the text of the Rosetta Stone into a codebreaking program, it will quickly identify the particuliar passage. It will probably be the first passage that was deciphered.