Kryptos : K2. What is the origin of the “abscissa” keyword? I'm studying the Kryptos sculpture with its cryptographic puzzles K1 to K4.

Similar to the "palimsest" keyword for K1, the keyword "abscissa" for K2 was determined by brute-force.

To better understand the puzzle as a whole and ultimately solve K4, it's important to understand how the "agent in the field" might have discovered these keywords.

One suggestion is that the keyword "abscissa" is derived from the plaintext of K1 which reads:


  BETWEEN SUBTLE SHADING AND THE ABSENCE OF LIGHT LIES THE NUANCE OF IQLUSION


Which, given a sort of "cryptic crossword" reading can give you:


Between "Subtle Shading And" -> "SSA"
... the ABSence -> "ABS"
... of Light (speed of light == "C" in physics) -> "C"
... lies the nuance of Iqlusion -> "I"


And with standard sort of anagram "fun", one comes up with "ABSCISSA."

Not very strong, but maybe believable.

Is there a better theory out there?
I think the best theory is crib-dragging the phrase "virtuALLYINVISIBLE" from the morse code sections. This will line up with "itwastotALLYINVISIBLE" from K2 and reveal the entire keyword, repeating and removing any doubts.

Come to think of it, it may very well have been the intension of Sanborn to have us decode K2 first by this method, and then from K2's ending (IDBYROWS/XLAYERTWO) derive the word palimpsest, because that´s basically what it is. One text scraped away to make room for another text and hinted at by the use of "LAYER TWO".