Cryptology

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Across
  1. 2. knightly cross
  2. 3. tribal group that stymied the Japanese
  3. 6. Holmes' men
  4. 9. a regular message
  5. 14. the sound of waves
  6. 15. scrambled eights?
  7. 16. flag-waving
  8. 17. a system used to encrypt plaintext
Down
  1. 1. anagram, for example
  2. 4. process, process, process
  3. 5. knowing this about letters helps
  4. 7. biblical code
  5. 8. a shifty emperor
  6. 10. Brit who developed a computer during WWII
  7. 11. a puzzling German?
  8. 12. dits and dahs could spell his name
  9. 13. it makes sense