Historically, Skype has faced legitimate security issues that hackers exploited. These were fixed by Microsoft and did not involve "activation codes" for the public:
: Some malicious tools may even install ransomware, locking you out of your device until a fee is paid. Known Skype Vulnerabilities
In reality, searching for or downloading these "codes" often leads to severe security risks, including malware infection and identity theft. The Reality of "Activation Code" Scams