Hate to cite to TIME, but here you go:
http://time.com/4933386/donald-trump-secret-pardon-law/
AS TO PARDONS AND SECRET PARDONS
All of the above-referenced post is true, with one HUGE CAVEAT: the Office of the Pardon Attorney has to be used for the public records laws to take effect. The President has inherent authority to simply sign a document himself and issue a pardon. The Office of the Pardon Attorney is an explicit creature of the Executive – it is governed by regulations promulgated by DOJ. See U.S. Const., Art. II, Sec. 2 (“[the president] shall have Power to Grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment”); 28 C.F.R. §§ 0.35, 0.36.
I'm not even sure that the Congress could pass a law requiring pardons to be conducted in a certain way. Based on the way the Constitution is worded, the power is absolutely in the hands of the president and it is for the executive to determine the manner in which pardons are granted and whether or not they are made public. It has been customary that they are made public, but there is no legal obligation that they be made public, or that the Office of the Pardon Attorney even be read into a specific pardon. The only reason FOIA comes into play is WHEN the Office of the Pardon Attorney is used. There is, however, no constitutional or other legal requirement that the Office of the Pardon Attorney be used.
What this means is that HUSSEIN probably wrote himself a SECRET PARDON that read something like this: I, HUSSEIN, hereby pardon myself for all offenses against the United States from [insert date of birth] to [insert final day as president].
Take a look at Nixon's pardon – it specifies only Article II as the legal basis. Also of interest is that Nixon was pardoned for offenses during a specific time period. Available here: https://www.gpo.gov/fdsys/pkg/STATUTE-88/pdf/STATUTE-88-Pg2502.pdf
I'm seriously in debt, but if I had any money, I'd bet it all that HUSSEIN handed out SECRET PARDONS like fucking candy, and they were for LIFETIMES (e.g., the Bushes, Clintons, and himself, among many). The race is on to get rid of President Trump not because they are worried about criminal prosecution for crimes before January 2017, but because they are worried about how it’s going to look when the pardons become public. As President Trump tweeted on June 4, 2018 (he’s teasing the information, in my view), “As has been stated by numerous legal scholars, I have the absolute right to PARDON myself, but why would I do that when I have done nothing wrong?”