Officials in Stratford, Ont. paid just over $75,000 to unlock the city's data after a cyber attack in April that inserted malware onto its servers.

The city says the attacker began encrypting its systems on the morning of April 14. Within five hours, the city had disconnected its servers from the internet and disconnected users to halt the infection.

Six physical servers and two virtural servers were affected, as well as some of the city's systems, making them unavailable to users.

The city began negotiating with the attackers on April 17 and by April 25, decryption was underway, with all systems back to normal by April 29, two weeks after the attack began.

To regain access to its data, the city paid the attackers the equivalent of $75,091.30 in Bitcoin, but has since submitted an insurance claim for all the costs associated with the incident.

Deloitte LLP, a cyber incident response company, was hired to monitor and assess the situation and was able to confirm that no personal information was disclosed as a result of the incident.

The contractor also said things could have been worse had the city not already had a number of security controls in place.

An investigation by Stratford police and the OPP Cyber Crime Unit is ongoing, so no details are being released at this time.