1 (act of) proving, attesting, verifying 2 proof, verification 3 (act of) validating 4 validation 5 (act of) determining 6 determination 7 (act of) affirming 8 affirmation 9 (act of) evidencing 10 evidence 11 (act of) arguing, disputing 12 argument, dispute 13 (act of) authenticating (in computing) 14 authentication (in computing)