ciphertext vs encryption

ciphertext

noun
  • Encoded text, text that is unreadable. 

encryption

noun
  • The process of obscuring information to make it unreadable without special knowledge, key files, or passwords. 

  • A ciphertext, a cryptogram, an encrypted value. Usually used with the preposition "of" followed by the value that is hidden in it. 

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