+==============================================================================+
|  DECRYPTION STATION — PUZZLE #2960                                |
+==============================================================================+

  CIPHER TYPE:     LUHN
  SECURITY LEVEL:  1/7

  STATUS:          [SOLVED]


  MISSION BRIEFING
  ----------------
Credit card PAN with Luhn check digit verification. Masked: ************5431. Length: 16. Verify the check digit is valid.

  INTERCEPTED DATA
  ----------------





> pan:
  4916835498765431



> hint:
  Double every second digit from the right. Sum all digits. Compute (10 - (sum % 10)) % 10. PAN: 4916835498765431. What is the check digit?



> answer format:
  single digit 0-9 (Luhn check digit)





  [INTEL] Pool fill: luhn diff 1


  DECRYPTION INPUT
  ----------------

  [PUZZLE ALREADY SOLVED]



  REVEALED ANSWER
  ---------------
  4


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