Health Minister Stephen Donnelly has described initial tests on the decryption key supplied by the health service IT hackers as “positive”.

The key was made available on Thursday evening almost one week after the IT system was targeted in a ransomware attack.

The HSE was forced to close down all of its IT services as a result of the attack, causing widespread delays and the cancellation of appointments at hospitals across the country.

Mr Donnelly said work was being carried out to ensure the validity of the key.

“The initial results are positive but obviously it’s a detailed technical piece of work and we need to be absolutely sure this will help restore the health systems rather than potentially cause further harm,” the minister told RTE’s Morning Ireland programme.

He added that “good progress” was being made in separate attempts to restore the IT systems across the country.

Mr Donnelly said that as of Thursday evening some of the most important IT systems were back up and running at a local level in some hospitals. These include imaging software for radiology and some patient administration systems.

But he said radiation oncology remained a problem and that the restoration of these services is an “absolute priority” for the HSE.

Mr Donnelly told the programme it was “unclear” why the decryption key was being made available and that it “came as a surprise” to the Government.

He added that there could be “any number of reasons” behind the move, and it would not be useful for him to speculate.

The Wicklow TD also reiterated that the Irish Government did not pay any ransom to the hackers involved in the attack.

“Categorically, no ransom has been paid by this Government directly, indirectly, through any third party or in any other way. Nor will any such ransom be paid,” he said.

Mr Donnelly also told the programme that the Government was taking the threat by the hackers that data would be uploaded online “very seriously”.

Hackers have reportedly threatened to release patient data on Monday if a ransom is not paid.

He appealed for anyone who is contacted about their information to bring it to the attention of the gardai.

On Thursday the HSE’s chief executive, Paul Reid, described the “catastrophic” impact of a “stomach-churning” hack of its IT systems.

Mr Reid criticised the attack as a “callous act” and said it was an attack on health workers who have been working “relentlessly” throughout the coronavirus pandemic.

The number of appointments in some areas of the system has dropped by 80% as health workers grapple with paper records while work continues to recover IT systems.

The National Cyber Security Centre and the Garda National Cyber Crime Bureau are carrying out an international investigation into the attack.

PA Media