Files with adk suffix may also be encrypted files affected by the Angry Duck ransomware.
There is one other file type using
the ADK file extension!
.adk - OS/2 saved SKF format
ADK file extension - Angry Duck ransomware affected file
What is adk file? How to open adk files?
File type specification:
File extension adk seems to be also used by a ransomware labeled as Angry Duck, which encrypts users files and then changes their suffix. It then demands 10 BC for the decryption key.