By my reckoning those memos were work product of his employment and, as such, not his personal property to be casually tossed around.
By admitting this Comey is even dumber than I previously thought he was.
Contemporary notes taken by a member of executive branch of a conversation between that official and the president are not the personal property of the official. After Comey was fired, those notes were no longer his notes to leak. By directing a “Friend” to leak the contents of that memo, Comey apparently committed a crime. In the end we may find that all the other leaks of the FBI investigation were coming from “Friends” of Comey.