The importance of confidential files is often relative to the situation at that time. With the passage of time, the disclosure of files will no longer affect the parties and related institutions, so it can be decrypted.
Decrypting files can help latecomers understand the cultural background and decision-making ideas of the incident, which is a valuable intellectual wealth. As a country, increasing the total wealth of society means strengthening national strength, so it is necessary to decrypt expired secrets so that more people can use them.
1972, president Nixon issued executive order 1652, which shortened the closed period of confidential official files formed by government agencies from 50 years to 30 years.
1978, president Carter issued the presidential executive order 12065, which further stipulated the steps of declassifying confidential official files, requiring government agencies to declassify and inspect confidential files that have expired for 20 years and make them as open as possible to the public. If they can't open them after 20 years, they will be automatically decrypted at the end of 30 years and must be opened.
As a government agency, the CIA must implement the relevant government regulations on file management.