In some countries some parts of history books of students have been removed by authorities of the time. For example, it has happened for Achaemenid Empire (a part of ancient Iran history) 2 years ago in history books of Iranian students. It is a kind of ideological censorship but I am finding for a better term or word to describe it.
Iranian authorities justified it as an attempt to focus on the Islamic part of Iran history and avoid of reading something complicated which may not be according to Islamic culture of Iran nowadays.
However, Iranians think there is nothing offensive and criminal in those ages but it has been removed because talks about a different religion, handwriting, and culture that Iranians had and caused golden ages for Iran history without Islamization. It is ironically strange because the other authorities remove dark histories like criminal attacks and genocides but Iranian authorities removed the most glorious part of Iran history! I think we have to find or create a new word to describe it if there is nothing similar!
Censoring is too broad and general. The word or phrase should not be one that is used for censoring sexual or offensive materials from art or literature, or removing something which seems vulgar or offensive. Historical revisionism might be the correct kind of word, but it refers to Communism ideas about revision about the history, religion, and political ideas, so it may be a correct word for North Korea but not about Iranian kind of it.