Undeciphered codes and unsolved ciphers — the texts that have resisted every attempt to read them. 12 case files in the archive.
Five confirmed Northern California murders 1968-1969 by an unidentified killer who sent taunting letters and ciphers. Z408 solved 1969; Z340 solved December 2020.
A 15th-century manuscript at Yale, written in an alphabet that matches no known writing system. Carbon-dated to 1404-1438.
An unidentified man found dead on an Adelaide beach in 1948. Identified July 2022 via DNA genealogy as Carl 'Charles' Webb. Cause of death still unknown.
The US Army Signal Intelligence Service's decryption of Soviet diplomatic cables. Gene Grabeel's 1943 start; Meredith Gardner's 1946 breakthrough.
Three ciphertext documents published in 1885. B2 decrypted using the Declaration of Independence as key; B1 and B3 undeciphered after 140+ years.
The undeciphered writing system of the Harappan civilization. ~4,000 inscribed objects, ~400 base signs, short inscriptions.
Fired clay disc discovered July 3, 1908 by Luigi Pernier at the Minoan palace of Phaistos. 45 distinct signs in spiral arrangement.
The encrypted sculpture by Jim Sanborn at CIA headquarters in Langley. The four ciphertexts, the three solved passages, the famously unbroken K4, the artist clues (BERLIN, CLOCK, NORTHEAST), and the 2025 archival discovery and auction of the solution.
The enciphered note the composer Edward Elgar sent to Dora Penny in 1897. The 87 squiggle-characters, the single-alphabet structure, the failed solutions, and why a short message from a known sender has never been read.
Luigi Serafini 1981 illustrated encyclopedia of an imaginary world written in an invented script. The asemic writing, the partly decoded page numbers, and the artist own statement that there is no hidden meaning.
The ~450-page manuscript in an unknown script held by the Hungarian Academy of Sciences. The religious illustrations, the hoax-versus-genuine debate, and the contested 2018 Kiraly-Tokai decipherment as a coded Christian prayer book.
The 18th-century enciphered manuscript cracked in 2011 by Kevin Knight, Beata Megyesi, and Christiane Schaefer using computational methods. The decipherment revealed the rituals of a German secret society, the Oculists.