Universities and NHS trusts in England have been hit hard by ransomware in the last year, according to Freedom of Information requests carried out by two cybersecurity firms.
Bournemouth University, which boasts a cybersecurity centre, has been hit 21 times in the last 12 months.
Twenty-eight NHS Trusts said they had been affected.
Ransomware is a form of computer malware which encrypts files and then demands a ransom for their release.
It can travel via email or hide in downloadable files and programmes from corrupted sites and applications, and the ransom is usually payable in bitcoins.
Cybersecurity firm SentinelOne contacted 71 UK universities. Of the 58 which replied, 23 said they had been attacked in the last year.