Can you recover the matrix & Setting?
Having solved the headlines we can construct a partial matrix of plain and cipher equivalents for each headline. From this can you recover the full matrix and the Setting? If not, read on below.
We have recovered these five headlines in the previous step:
GJSUJD GDCUUSU DHNPGCE: USEJIS TOSSU PE XJEPG.
caesar crosses rubicon: senate flees in panic.
BMKKLRK DMK GHMU MUJ DRUNAI GVVQ.
cassius has lean and hungry look.
YVWPX FATXL KEVPAPF EIWOQ ABXL WD HEVYC.
crone gives warning about ides of march.
VKSFSE TBOKTZTBQFNR TB HTXXNK IXLF
brutus incriminated in killer plot
TWJA WHLBHP VWTKHLR WHZ UBJJBIR KWJR.
mark antony laments and borrows ears.
From the solved headlines we can build a partial enciphering matrix:
abcdefghijklmnopqrstuvwxyz
JNG.ST..P..O.ECX.DUIH.....
M.BJH.NDL.QG.UV..AK.R...I.
EIYBXDFCA...HPW..VLQOTK...
QVORN...T.HXZBLI.KEFS.....
WU.ZK.....AVTHB..JRL..I.P.
Using symmetry, as explained in the article on Quagmire 3, the complete matrix is recovered. You can use the program here to do the job. Copy the five headlines and their solutions (as above) and paste them into the program and click the ‘solve’ button. You will get:
abcdefghijklmnopqrstuvwxyz
JNGQSTVKPZROWECXADUIHBYLFM
MSBJHPNDLWQGFUVOZAKXRETCIY
EIYBXDFCASGMHPWJNVLQOTKZRU
QVORNYCUTAHXZBLIDKEFSGMPWJ
WUNZKXEQOYAVTHBCMJRLDSIGPF
The Setting PLATO is visible under plain ‘i’, which also tells us that 'I' is the first letter of the mixed alphabet.