Source : Webster's Revised Unabridged Dictionary (1913)

Authenticate \Au*then"ti*cate\, v. t. [imp. & p. p.
   {Authenticated}; p. pr. & vb. n. {Authenticating} (?).] [Cf.
   LL. authenticare.]
   1. To render authentic; to give authority to, by the proof,
      attestation, or formalities required by law, or sufficient
      to entitle to credit.

            The king serves only as a notary to authenticate the
            choice of judges.                     --Burke.

   2. To prove authentic; to determine as real and true; as, to
      authenticate a portrait. --Walpole.

Source : WordNet®

authenticated
     adj : established as genuine [syn: {attested}, {documented}]