Classified National Security Information Protection Act Article 39-1

Information originally approved for permanent classification under this Act shall be re-approved within two years from the date of the amendment and promulgation of Article 12, and the classification period shall be calculated from the date of the original approval. If the re-approval has not been completed within two years, it shall be deemed to be declassified from the expiration date and handled according to Article 31.For information with a classification period exceeding thirty years, if the extension of such period is approved according to the preceding paragraph, the extended period shall be calculated from the day after the original period reaches the thirtieth year, and the extensions shall be approved in accordance with Article 12.
中文原文 國家機密保護法第39-1條
原依本法核定永久保密之國家機密,應於第十二條修正施行之日起二年內,依本法重新核定,其保密期限溯自原先核定之日起算;屆滿二年尚未重新核定者,自屆滿之日起,視為解除機密,依第三十一條規定辦理。
國家機密保密期限已逾三十年者,依前項規定重新核定延長保密期限,延長之期限應溯自國家機密保密期限屆滿三十年之次日起算,依第十二條規定逐次核定延長。

English translation for reference only; the Chinese text prevails. Not legal advice.