The most common and most likely answer to this crossword clue is the 8 letter word PATENTEE
I've seen this crossword clue in Independent
P
A
T
E
N
T
E
E
More clues leading to the result PATENTEE
Buddy explains!
The straight part
We know that "One has certain rights" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one has certain rights = patentee.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PATENTEE mean?
PATENTEE noun- One to whom a grant is made, or a privilege secured, by patent.