It is closely related to cryptanalysis — the difference being that the original document was not deliberately written to be difficult to decipher.
Some people have also used the word metaphorically to mean something like 'understanding'.
Examples of script decipherment:
Famous documents that have been the subject of actual or attempted decipherment:
A newly discovered column in the hieroglyphic test on La Mojarra Stela 1: a test of the epi-Olmec decipherment.
Jul 11, 1997; The remains of a distinctive script tradition are found on monuments from southern Mexico, ranging from Cerro de las Mesas in the...
Andis Kaulins. Stars, stones and scholars: the decipherment of the megaliths as an ancient survey of the Earth by astronomy.(Brief Article)(Book Review)
Jun 01, 2004; ANDIS KAULINS. Stars, stones and scholars: the decipherment of the megaliths as an ancient survey of the Earth by...