ciphertext vs plain text

ciphertext

noun
  • Encoded text, text that is unreadable. 

plain text

noun
  • Text or any data that is to be encrypted (as opposed to ciphertext). 

  • Data which consists only of human-readable text, as opposed to machine-readable binary data or formatting markup. 

adj
  • Consisting only of plain text. 

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