If the ransomware used an (because your computer had no internet connection during encryption, or the C2 server was unreachable), you are in luck. Security researchers have released free decryption tools.
Modern ransomware typically uses or RSA algorithms. happ decrypt
The .happ extension is a sign of STOP ransomware, but not all hope is lost. —it may recover everything. If the tool says your key is “online,” your only practical options are backups or waiting for a future decryptor update. If the ransomware used an (because your computer
: The software implements an automatic version fallback logic. If a specific version fails, it cycles through available keys (e.g., crypt4 → crypt3 → crypt2 → crypt ) to find the correct match. or the C2 server was unreachable)