The "limbs in the loch" murderer William Beggs has secured an agreement with prison authorities giving him access to a computer.
Beggs murdered teenager Barry Wallace
Beggs has been working on an appeal against his conviction and sentence.
The killer planned to take legal action against the prison service to establish his right to use the equipment.
Beggs, 40, murdered 18-year-old Barry Wallace and then cut up his victim before dumping body parts in Loch Lomond and off the Ayrshire coast.
The Scottish Prison Service had originally ruled that Beggs should not have equipment on which data could be stored secure from examination by jail staff.
Beggs was convicted at the High Court in Edinburgh of murdering Mr Wallace after a Christmas night out in 1999.
Beggs, originally from Northern Ireland, picked up the teenager in Kilmarnock, took him back to his flat in the town and sexually assaulted him.
He later murdered Mr Wallace and dismembered his body.
Parts of Mr Wallace's body were found in Loch Lomond and his head was recovered from an Ayrshire beach.
At the time of the trial, a police officer who had investigated an earlier charge against Beggs described him as "a serial killer in the making".