encrypted vs masked

encrypted

adj
  • Being in code; having been encrypted. 

masked

adj
  • Concealed; hidden. 

  • Wearing a mask or masks. 

  • Personate. 

  • Characterized by masks. 

  • Having the anterior part of the head differing decidedly in color from the rest of the plumage. 

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