Malware that encrypts data until a ransom has been paid is on the rise, according to cyber crime experts who have spotted a copycat of a famous version of the security threat.
The growing trend has even been given its own category, ransomware, and security firm IntelCrawler said it is beginning to proliferate.
The most famous example, CryptoLocker, has claimed thousands of victims this year, and IntelCrawler researchers said they have found another, called Locker, which demands £92 to restore encrypted files.
The ransomware has been spotted in Russia, Europe and America, and is spread via infected files placed on compromised websites and through files disguised as MP3s.
It deletes the original files from the infected computer, replacing them with encrypted versions of the data, which can only be decrypted once the ransom is paid to obtain the key to the enigma.
IntelCrawler's Andrey Komarov told the BBC: "Our researchers are working on the universal decryption software in order to help the victims."