My question in particular is:
Does using the same key multiple times ease bruteforcing the used keyfile or passphrase?
My question in particular is:
Does using the same key multiple times ease bruteforcing the used keyfile or passphrase?
LUKS's current default is AES-XTS. AES-XTS does not have significant chosen plain test attacks.
No it should not be an issue. The weak link is typically your password. Also for key generation consider using an option like PBKDF2 with SHA-512 with the highest number of iterations practical for you. This will increase the time needed to unlock. Try to make it a second or more instead of small fractions of a second. This makes it harder for the attacker to brute force test all possible keys. recommended-options-for-luks-cryptsetup