Locky is a type of ransomware that first appeared in 2016. It encrypts files on a victim's computer, making them inaccessible until a ransom is paid. Typically, it spreads through malicious email attachments or links, often disguised as legitimate documents. Once Locky infects a system, it generates a unique key to encrypt files and demands payment in Bitcoin for the decryption key. Victims are usually given a limited time to pay, increasing the urgency and pressure to comply. Cybersecurity experts recommend regular backups and caution when opening emails to avoid such threats.