Julian Assange, 47, will not face a full extradition hearing until next year.
Assange appeared by video link from prison on Friday, 14 June, at a hearing to decide the next step in the process to extradite him to the United States.
Judge Emma Arbuthnot decided Assange would face a five-day extradition hearing on 25 February 2020.
Assange's lawyer, Mark Summers, said the case represented an "outrageous and full-frontal assault on journalistic rights."
Assange is in London's Belmarsh prison where he is serving a 50-week sentence for jumping bail and hiding in the Ecuadorean embassy after being sought for extradition to Sweden over rape allegations.
He appeared, dressed in a grey t-shirt and wearing black-framed glasses, and spoke only briefly.
Ben Brandon, a lawyer representing the United States, ran through a summary of the accusations against him and when he said Assange had cracked a US defence network password, the Australian-born WikiLeaks founder interrupted and said: "I didn't break any password whatsoever."
Mr Brandon said the case "related to one of the largest compromises of confidential information in the history of the United States."
He was too ill to appear at his last hearing but has recovered sufficiently to appear by video link for the Westminster Magistrates' Court hearing in central London.
Dozens of people protested outside the court, urging the British government to stand up to the Trump administration and refuse to extradite Assange whose only crime, they claimed, was to expose the US's nefarious activities around the world.
The US want to prosecute Assange under the 1917 Espionage Act, blaming him for directing WikiLeaks' publication of a huge trove of secret documents which they say endangered informants who provided confidential information to US and coalition forces in Iraq and Afghanistan.
Assange claims he is a journalist whose right to free speech is protected by the First Amendment of the US Constitution.
On Friday he was told his next court appearance would not be until October. His lawyers are appealing against the sentence for the bail offence and hope he will be freed from jail before the autumn.