The Conti Ransomware uses AES-256 encryption via a hard-coded public key. The unique factor is the use of multiple threads for the encryption process, which allows faster encryption as compared to other ransomwares. The ransomware uses a CreateIoCompletionPort() call to create 32 thread instances which work simultaneously to encrypt files. After encryption, the ransomware adds extension to all the encrypted files. It can be seen in the image below