Ransomware is a type of malicious software that, once installed, blocks access to a victim’s computer systems or data by encrypting them. The attacker then demands a ransom payment, often in cryptocurrency, in exchange for a decryption key to restore access. Some modern ransomware attacks use “double extortion,” where they also steal sensitive data and threaten to release it if the ransom isn’t paid.
Starting from around 2012, the use of ransomware scams has grown internationally. There were 181.5 million ransomware attacks in the first six months of 2018. This record marks a 229% increase over this same time frame in 2017. In June 2014, vendor McAfee released data showing that it had collected more than double the number of ransomware samples that quarter than it had in the same quarter of the previous year. CryptoLocker was particularly successful, procuring an estimated US$3 million before it was taken down by authorities, and CryptoWall was estimated by the US Federal Bureau of Investigation (FBI) to have accrued over US$18 million by June 2015.
Source: Gemini AI Overview - 11/6/2025