The city of Stratford agreed to pay an attacker more than $75,000 worth of Bitcoin in exchange for decryption keys to unlock its information systems following an April cyber attack.

According to an information update on the Stratford website, the city paid the attacker 10 Bitcoin — a digital form of currency — which was then valued at $7,509.13 each.

The city said it has submitted a cyber insurance claim, which should foot most of the bill. The city's deductible is $15,000.

The cyber attack happened on April 14, after an attacker installed malware on six physical servers and two virtual ones. The city didn't return to normal business operations until April 29.

An investigation by the consulting company Deloitte found that no personal information was lost or disclosed as a result of the attack.

The city said it has since beefed up its security measures to prevent another attack from happening.

A police investigation into the cyber attack continues.