He is not permitted to give interviews or make public statements and yet he has used YouTube three times to make short audio statements, setting off a media sensation in Peru as he rallies supporters and trades insults with political enemies.
The legal loophole that let Mr Fujimori go online has unnerved Peru's justice minister, and government lawyers are trying to come up with new legislation, for the self-broadcasting internet age, to further restrict inmates' speech.
Like other prisoners, Mr Fujimori is not allowed to have a computer or a mobile phone, but he does have access to a public phone on the police base outside Lima where he is held. So he delivers tweets and recorded messages to supporters over the pay phone - and they post them online.
It's become a headache for President Ollanta Humala's government.
Mr Humala has refused to pardon the 75-year-old Fujimori, who in 2009 became the world's only ex-president to be convicted by his own country's judiciary for crimes committed in office.
While awaiting his sixth trial on more corruption charges, Mr Fujimori passes his days writing his memoirs, painting and listening to opera, especially Maria Callas.