Jeremy Hammond, the Anonymous hacktivist who released millions of emails relating to the private intelligence firm Stratfor, has denounced his prosecution and lengthy prison sentence as a “vengeful, spiteful act” designed to put a chill on politically-motivated hacking.

Hammond was sentenced on Friday at federal court in Manhattan to the maximum 10 years in jail, plus three years supervised release. He had pleaded guilty to one count under the Computer Fraud and Abuse Act (CFAA) flowing from his 2011 hack of Strategic Forecasting, Inc, known as Stratfor. In an interview with the Guardian in the Metropolitan Correction Center in New York, conducted on Thursday, he said he was resigned to a long prison term which he sees as a conscious attempt by the US authorities to put a chill on political hacking.

He had no doubt that his sentence would be long, describing it as a "vengeful, spiteful act". He said of his prosecutors: "They have made it clear they are trying to send a message to others who come after me. A lot of it is because they got slapped around, they were embarrassed by Anonymous and they feel that they need to save face.”

Most pointedly, Hammond suggested that the FBI may have manipulated him to carry out hacking attacks on “dozens” of foreign government websites. During his time with Anonymous, the loose collective of hackers working alongside WikiLeaks and other anti-secrecy groups, he was often directed by a individual known pseudonomously on the web as “Sabu”, the leader of the Anonymous-affiliated group Lulzsec, who turned out to be an FBI informant.

Hammond, who is under court orders restricting what he says in public, told the Guardian that Sabu presented him with a list of targets, including many foreign government sites, and encouraged him to break into their computer systems. He said he was not sure whether Sabu was in turn acting on behalf of the FBI or other US government agency, but it was even possible that the FBI was using Sabu’s internet handle directly as contact between the two hackers was always made through cyberspace, never face-to-face.

“It is kind of funny that here they are sentencing me for hacking Stratfor, but at the same time as I was doing that an FBI informant was suggesting to me foreign targets to hit. So you have to wonder how much they really care about protecting the security of websites.”

In the interview, conducted in a secure prison meeting room hours before the 28-year-old Chicagoan was sentenced, he was sanguine about his prospects. “I knew when I started out with Anonymous that being put in jail and having a lengthy sentence was a possibility. Given the nature of the targets I was going after I knew I would upset a lot of powerful people.”

Dressed in a brown prison jump suit, and with a long wispy goatee and moustache (he planned to shave both off before the sentencing hearing), Hammond was scathing about the way the CFAA was being twisted in his view for political ends. “They are widening the definition of what is covered by the Act and using it to target specifically political activists,” he said.

He invoked the memory of Aaron Swartz, the open-data crusader who killed himself in January while awaiting trial under the CFAA for releasing documents from behind the subscription-only paywall of an online research group. “The same beast bit us both,” Hammond said. “They went after Aaron because of his involvement in legitimate political causes – they railroaded charges against him, and look what happened.”

Hammond has been in custody since March 2012 having been arrested in Chicago on suspicion of the Stratfor leak of millions of emails that were eventually released by WikiLeaks as the Global Intelligence Files. His sentence is an indication of the aggression with which prosecutors have been pursuing political hackers in the US – other Anonymous members in Britain involved in the breach of Stratfor were sentenced to much shorter jail terms.

Hammond stressed that he had not benefitted personally in any way from the Stratfor email release, that exposed surveillance by private security firms on activists including Anonymous members themselves, Occupy protesters and campaigners in Bhopal, India involved in the push for compensation for victims of the 1984 industrial catastrophe. “Our main purpose in carrying out the Stratfor hack was to find out what private security and intelligence companies were doing, though none of us had any idea of the scale of it.”

Paradoxically, Hammond insists that he would never have carried out the breach of Stratfor’s computer system had he not been led into doing it by Sabu – real name Hector Xavier Monsegur – the fellow hacker who is himself awaiting sentencing having pleaded guilty to 12 hacking-related criminal charges. “I had never heard of Stratfor until Sabu brought in another hacker who told me about it. Practically, I would never have done the Stratfor hack without Sabu’s involvement.”

Hammond discovered that Monsegur was an FBI informant the day after his own arrest. As he was reading the criminal complaint against him, he saw quotes marked CW for “co-operating witness” that contained details that could only have come from Sabu.

“I felt betrayed, obviously. Though I knew these things happen. What surprised me was that Sabu was involved in so much strategic targeting, in actually identifying targets. He gave me the information on targets.”

Part of Sabu’s interest in him, he now believes, was that Hammond had access to advanced tools including one known as PLESK that allowed him to break into web systems used by large numbers of foreign governments. “The FBI and NSA are clearly able to do their own hacking of other countries. But when a new vulnerability emerges in internet security, sometimes hackers have access to tools that are ahead of them that can be very valuable,” he said.

Looking back on his involvement with anonymous, the Chicagoan said that he had been drawn to work with Anonymous, because he saw it as “a model of resistance – it was decentralised, leaderless.” He grew increasingly political in his hacking focus, partly under the influence of the Occupy movement that began in Wall Street in September 2011 and spread across the country.

Chelsea Manning, the US soldier formerly known as Bradley who leaked a massive trove of state secrets to WikiLeaks now serving a 35-year sentence in military jail, was a major influence on him. Manning showed him that “powerful institutions – whether military or private security firms – are involved in unaccountable activities that the public is totally unaware of that can only be exposed by whistleblowers and hackers”.

Hammond has often described himself as an anarchist. He has a tattoo on his left shoulder of the anarchy symbol with the words: “Freedom, equality, anarchy”. Another tattoo on his left forearm shows the Chinese representation of “leader” or “army”, and a third tattoo on his right forearm is a glider signifying the hacking open-source movement that is drawn from the computer simulation Game of Life .

He says he plans to use his time in prison “reading, writing, working out and playing sports – training myself to become more disciplined so I can be more effective on my release”. As to that release, he says he cannot predict how he will be thinking when he emerges from jail, but doubts that he would go back to hacking. “I think my days of hacking are done. That’s a role for somebody else now,” he said.