Using cheap personal computers at home, Neil Woods, 26, of Chadderton, Oldham, Greater Manchester, and Karl Strickland, 22, from Liverpool, who 'spoke' on screen under codenames but never met, ran up bills for legitimate users running to tens of thousands of pounds over two years, Southwark Crown Court in south London was told.
They swapped other people's user identifications and authorisation codes enabling them to dial into systems belonging to companies, education establishments, British Telecom, the United States space agency Nasa, and the European Community. They kept copies on disk of much of their hundreds of hours of hacking.
There was evidence in the case referring to networks in the US, France, Iceland and Germany, James Richardson, for the prosecution, said. Both had pleaded guilty at an earlier hearing to conspiring to obtain telegraphic services dishonestly, and engaging in the unauthorised publication of computer information.
Woods, a graduate in computer science from Manchester University, also admitted causing damage to a computer owned by the then Polytechnic of Central London.
Mr Richardson told Judge Michael Harris that Woods, known in the hacking world as 'pad', and Strickland, nicknamed 'Gandalf' (the wizard in Tolkien's Lord of the Rings), were frequent illegal users of Janet, an education network in Britain linking universities, polytechnics and other academic institutions. The court was told how he had gained access by telephone to computers at the Polytechnic of Central London and had changed the message when users signed on to read simply 'Hi'.
When engineers had investigated the fault they were greeted with the message 'We are the Janet hackers.'
Mr Richardson said that the computer's makers had quoted a price of pounds 230,000 to rid the system of the faults. But he added that the authorities, finding the system was still workable, had in fact decided not to pay for the repairs.
The hackers also ran up huge bills for legitimate users with accounts at PSS, a British Telecom computer network. 'Many of the companies and organisations whose user identifications were being wrongly used were unaware of their unauthorised use because of the difficulty distinguishing between authorised and unauthorised activity,' Mr Richardson said. 'Bearing in mind charges relating to just two companies for two quarters, when bills of over pounds 7,000 were run up . . . the court can be satisfied that the value of the charges rounded down to the very lowest figure would have been pounds 25,000.' During one of their exchanges on computer, Woods typed on his keyboard: 'We want to be full-time hackers.' Strickland replied: 'If it moves, hack it.'
Mr Richardson said that during other sessions the two spoke of 'abusing' computer systems for hours and of 'smashing' data bases. On one occasion Strickland 'taunted' a computer operator who was logged on to the system he had hacked into.
Mr Richardson said that Strickland had correctly noted that running up someone else's telephone bill 'must be illegal'. However, when Woods said he was assured by another hacker that the activity was not illegal, Strickland decided to carry on.
At one stage Woods complained of being short of money and possibly needing to find a job. Strickland replied: 'I should, too, but I do not like the idea of work.'
In March, Paul Bedworth, a Yorkshire schoolboy who regularly communicated with Woods and Strickland, was cleared of similar charges by a jury, after a 15-day trial. Mr Bedworth, now 19 and a student of artificial intelligence at Edinburgh University, said in his defence that he had become addicted to hacking.
The case is expected to end today.