EntityQ735055· pop 5· linked from 8 articlesD'Agapeyeff cipherSign in to saveunbroken cipherConnectionscryptographyEntitycartographyEntitycryptanalysisEntitycipherEntityPolybius squareEntityletter frequencyEntityindex of coincidenceEntityElonka DuninEntityAmerican Cryptogram AssociationEntityCategories1939 in literatureUndeciphered historical codes and ciphers