DecipherCipher Hub / Crossing Lines

Cipher Challenge

Crossing Lines

Several plausible lines of attack present themselves in this mid-level Checkerboard challenge. Keep competing ideas in play, compare what each one explains, and be ready to revise a promising theory when the evidence asks you to.

Checkerboard

Source & status

Origin
Original to Decipher
Solution
Established

Ciphertext

TEONH ETPGA TAGNT LGESA TPGAG NGEHE HNONH ESNGE OLGES NGEHE OLOPG LHESP GEHES AGLHN SETLG ESESP GETEG NSATP SEGEG NGEGL OPHNH EGESE HPHET EGETE TETPH NGNGL GASEG ETETP HEGES EGNTP HPGAS AGEGL GNTLG EHEGL GATET AHEHP ONGAT ESEHP GATET PGNTP HPGAH NOEGE TNHPH EGEOP HPSNT PGATA HPGAH PGAGE GAHPG NGEOE HPHPS PHEGE GNONH EGAGE TESAT PGNTL GLHNT PGATA GPGEG EGAGN HEOLH PONGN HPTNH NGEHA ONGEG ASEGE GNTLG EGAON OPOEG EHEHN SAGEH EGESN GLGPT PTEOE ONGNG NTLGE HPHET EGEHE TPOPH LGPTP GETEG LHLGL GNTLG NTLHE HPONT ATLGN TLGEO PGLHE HNTLG NTLGL GNGAH PHPGA GETLG LTESA GLGPS PGETE HEGES EHPGA HNGNH EONSE GNTPG ATAGN TLGEH EHPON GNGEH EGEHA ONTPH EGETE SEHPO PHLGL HETPG ATAGE SNGEH EOLGA GETPT ATLOE HPHET PGATA HPOEH NGEHE SNGLG NTPHP GA.

Submit Flag

The Flag is the first 64 non-whitespace characters of the recovered Solution, or all of them when there are fewer. Keep cipher fillers.