History

Famous Unsolved Coded Messages

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Updated:3/7/2026
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Coded Message
Year Created
Origin
Status
Known For
Zodiac Killer's Z340 Cipher
1969San Francisco, USASolved 2020 (51 years later)Serial killer's taunting cipher sent to newspapers, cracked by amateur codebreakers in 2020, Z408 solved earlier
Voynich Manuscript
c. 1404-1438Unknown (possibly Italy)Unsolved220-page illustrated codex in unknown script and language, bizarre botanical drawings, defies all decryption attempts
Kryptos (CIA Sculpture)
1990CIA Headquarters, Langley, VA3 of 4 sections solved, K4 unsolvedJim Sanborn's sculpture at CIA HQ, final 97 characters still unsolved, even the CIA can't crack it
Beale Ciphers
c. 1820sBedford County, Virginia1 of 3 solved, treasure unfoundAllegedly describes location of buried gold/silver treasure worth $43M+, cipher #2 keyed to Declaration of Independence
Dorabella Cipher
1897EnglandUnsolved87 characters written by composer Edward Elgar to a friend, nobody knows the alphabet or the message
Shugborough Inscription
c. 1748-1763Shugborough Hall, EnglandUnsolved8 letters O-U-O-S-V-A-V-V carved beneath relief of Poussin painting, possibly Holy Grail clue, Bletchley Park failed
Phaistos Disc
c. 1700 BCECrete, Minoan civilizationUnsolvedFired clay disc with 241 stamped symbols in spiral, one-of-a-kind artifact, Bronze Age mystery
Tamam Shud Case (Somerton Man)
1948Adelaide, AustraliaCode unsolved, body identified 2022Dead man on beach with torn page from Omar Khayyam, coded letters on back, identity was finally solved via DNA in 2022
Chaocipher
1918USAAlgorithm revealed 2010 posthumouslyJohn Byrne's cipher machine offered to US government, rejected, kept secret for 90 years, family donated papers
Ricky McCormick's Encrypted Notes
1999St. Louis, MissouriUnsolvedTwo coded notes found in murdered man's pockets, FBI's top unsolved cryptanalysis case, may be key to homicide
D'Agapeyeff Cipher
1939EnglandUnsolved (author forgot key)Published as a challenge in a cryptography textbook, the author later admitted he couldn't remember how he encrypted it
Rohonc Codex
Unknown (pre-1743)Possibly HungaryUnsolved192-page codex in unknown writing system with religious illustrations, dismissed as hoax by some, 10 times Voynich's size
Copiale Cipher
c. 1730sGermanySolved 2011105-page manuscript of a secret society's initiation rituals, cracked using computational linguistics, revealed oculist lodge
Linear A
c. 1800-1450 BCEMinoan CreteUnsolvedScript of the Minoan civilization, predecessor to Linear B (which was deciphered), language itself is unknown
Zodiac Killer's Z13 and Z32
1969-1970San Francisco, USAUnsolvedShort ciphers claiming to contain the Zodiac's real name, too short to crack statistically, taunting 'My name is...'

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