Ryan Ackroyd, 25, from Mexborough, South Yorkshire, appeared in court on charges relating to the Lulzsec hacking of the CIA and the UK's Serious Organised Crime Agency.
Ackroyd entered no plea, and will appear at Southwark Crown court on 11 May.
Judge Howard Riddle granted Ackroyd bail him bail until 11 May, on the condition that he does not access the internet. He is also not able to have possession of a smart phone, or any other device that could access the internet.
Westminster Magistrates' Court heard that Ackroyd alleging attempted to access other sites illegally, such as the NHS and News International.
Jake Davis and Ryan Cleary appeared in court last autumn accused of hacking into websites including that of the UK's Serious Organised Crime Agency. The 17-year-old appeared at West London Youth Court on March 13.
Suggested For You
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements. Learn more