authenticity vs untruth

authenticity

noun
  • The quality of being genuine or not corrupted from the original, of having the same origin (or attribution, commitment, intention, etc.) as claimed. 

untruth

noun
  • The condition of being false; truthlessness. 

  • A lie or falsehood. 

How often have the words authenticity and untruth occurred in a corpus of books? (source: Google Ngram Viewer )