黑箱

hēixiāng
  1. black box
  2. flight recorder
  3. opaque system (computing)

CEDICT

computing

Entry Composition

1 黑 hēi
  1. black
  2. dark
  3. sinister
  4. secret
  5. shady
  6. illegal
  7. to hide (sth) away
  8. to vilify
  9. (loanword) to hack (computing)
2 箱 xiāng
  1. box
  2. trunk
  3. chest