Linear A is one of 2 characters or writing in Crete (one of the Greek islands). In addition to Linear A, Linear B was solved by Michael Ventris in 1952. But Linear A is still unbreakable, half read as it leads to Linear B. Although using the same language, if Linear B is applied to Linear A, the language is very Strange and unknown in any language. There is believed to be a connection between Linear A and The Phaistos Disk.
read here for The Phaistos Disk
World unsolved codes #2 Phaistos Disk
