as salam alaikum
there is not reliable isnad found for this hadith; it is therefore problematic to accept it from a mere technical perspective. On the other hand, several scholars have quoted it, like Fakhr al-Din al-Razi in his "Tafsir", Muhaqqiq al-Karaki amongst his "Rasa'il", Ibn Abi Jumhur al-Ahsa'i in "al-Ghawali al-Li'ali" and al-Majlisi in "Bihar al-Anwar" and Ibn 'Arabi in "al-Futuhat al-Makiyyah".
As far as its content, some scholars have raised the following objections:
1) The perfection of Allah is self-subsistent and so it is His knowledge, meaning that He is known by Himself and does not need someone else to be known.
2) The Qur'an says: "To Him belong the Most Beautiful Names" (7:180). The word "treasure" (كنز) implies a conception related to a solid-material reality while "there is nothing like Him" (42:11).
3) The word "hidden" (مخفيا) is past participle and needs an active participle which in the said case would be other than Allah.
In conclusion, its authenticity is not ascertained.
With prayers for your success.