authentication
au•then•ti•cateBrE /ɔːˈθentɪkeɪt/
NAmE /ɔːˈθentɪkeɪt/
verb
verb formsto prove that sth is genuine, real or true
word origin
~ sth The letter has been authenticated by handwriting experts.~ sth as sth Experts have authenticated the writing as that of Byron himself. 
au•then•ti•ca•tion /BrE ɔːˌθentɪˈkeɪʃn; NAmE ɔːˌθentɪˈkeɪʃn/ noun [uncountable]
