Puzzlemasters - Agent Penny Dropp's Puzzle

From: Agent Penny Dropp, HQ
Security Level: Top Secret – Eyes Only
Status: COMPROMISED

Agents,

We’ve intercepted a scrambled memo from an unknown source - codename SILENCER - believed to be a rogue operative embedded deep within HQ.

The message was heavily encrypted, transmitted using an obsolete Cold War cipher we haven’t seen in decades - a worrying sign.

Intel suggests it contains the trigger code for a system-wide blackout across HQ’s encrypted communications. If activated, we’ll lose all spy contact in the field - including tea break alerts.

We’ve managed to decipher some of the message, but the transmission is unstable and degrading fast. We need the code decoded and the threat neutralised immediately.

You’ve got one shot to crack the code and stop SILENCER before this, and all our comms, vanish for good.

This message will self-corrupt in… well, you get the idea.

Good luck,

Agent Penny Dropp

Senior Field Commander
“If it’s encrypted, it’s important. If it’s urgent, it’s probably on fire.”

We’ve decoded what we can, but the transmission is still heavily redacted. The device trigger looks to be a colour and three letters.

Knowing that this rogue operative is one of us, we’re convinced that the transmission contains everything you need to complete this mission... Decode the memo (it looks like some kind of letter shift code), work out what the redacted words are, and use these to figure out the trigger code for the device.

From previous missions, we know that you need to first identify which coloured button to press. We think Clues 1-4 reveal this. Then, we need to know which three letters to enter. Clue number 5 will reveal these. 

KCKM = MEMO

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