On the Subject of Silo Authorization

There’s no way to win. The game itself is pointless!

• Press the “Receive” button. After 20%–40% of the bomb’s remaining time has passed, or a minimum of 30 seconds, an encrypted message will be spoken. You may repeat the message as desired by pressing “Receive” again, still waiting 30 seconds after the button is pressed. If you strike, a new message is generated.
• Ignore the first part of the message. The important parts are:
  • the code (a color followed by “Alpha”);
  • two messages of four characters each (spoken one after another as an 8-character sequence);
  • an authentication code (4 digits).
• Obtain the Silo ID and the Launch Location as follows. Each consists of three base-36 digits. Take the values modulo 36.

  	Silo ID use first letter of SN instead of 0 (zero)	Launch Location
  1	number of battery holders	number of solvable modules
  2	number of batteries	number of unsolved modules
  3	number of port plates	number of solved modules

• Decrypt both messages as described in the section Encryption/Decryption below. The decrypted messages are 3 characters each (total of 6 characters).
• Multiply the first of those 6 characters with the first character of the serial number, the second with the second, etc., then add up the results. Letters are A=10, ..., Z=35.
• If this sum does not equal the received authentication code, your response message will be as follows:
  • 1st character of the first decrypted message
  • 2nd character of the second decrypted message
  • 3rd character of the first decrypted message

• Otherwise, if the first decrypted message matches an indicator on the bomb, or if there are no indicators and the message is “MRP”, respond with that first message.
• Otherwise, if each individual character in the second decrypted message is contained in the serial number, respond with that second message.
• Otherwise, respond with the following message:
  • 1st character of the second decrypted message
  • 2nd character of the first decrypted message
  • 3rd character of the second decrypted message
• Encrypt the response using any cipher that was not used by the received message. Prepend it with the digit identifying the cipher (0, 1, or 2).
• Construct the response authentication code as follows:
  • If your received code was “Red-Alpha”, use the Launch Location; otherwise, use the Silo ID.
  • Multiply the first of the 3 characters with the first character of the unencrypted response message, the second with the second, etc., then add up the results. Letters are A=10, ..., Z=35.
• Enter the authentication code, Silo ID, encrypted message and launch location into the module and press Send to disarm the module.

Encryption/Decryption

Take the first character of a message modulo 3 to find the decryption method.

0	Post-Modern: Move your character backward (decryption)/forward (encryption) by the first character in the Silo ID on a QWERTY keyboard. For example, with a Silo ID of 155, 9 -> 0, 0 -> Q, M -> 1, etc.
1	Rot18: Add I (18 in base 10) to your character. Keep your character in the range of 0–Z. For example, 0 -> I, 1 -> J, A -> S, etc.
2	MAtbash: Swap your character with the mirrored character in the alphabet. For example, 0 -> Z, 1 -> Y, A -> P, etc.