BERLIN – In the marble-lined hall of a former Prussian palace here today, former WikiLeaks spokesman Daniel Domscheit-Berg defended actions that have left the controversial whistleblowing site unable to receive new leaks online.

Introducing his new book Inside WikiLeaks, being released simultaneously today in 14 countries, WikiLeaks’ most prominent defector confirmed that he and other disaffected volunteers had taken the site’s software-based secure submission platform when they left the project, leaving the site technically unable to receive new material. The software was the intellectual property of one of the departing volunteers, he said.

In the process, the group also took with them a backlog of previously submitted leaked material — an action that has now prompted legal threats by WikiLeaks’ Berlin-based lawyer.

The 32-year-old German programmer said he and his group intend to return the material unused and unpublished, as soon as WikiLeaks can demonstrate the technical ability to keep the data and its sources safe. But WikiLeaks’ internal technical architecture has reverted to a primitive state, with little sign of progress in the months since the group’s departure, Domscheit-Berg said. The crippled submission system is effectively helping  to keep sources from unknowingly exposing themselves, he added.

“As a source, you can not compromise yourself today, because you can’t submit anything,” the German programmer said.

In a statement published by Der Spiegel, WikiLeaks lawyer Johannes Eisenberg called this concern for sources’ safety an “obvious justification,” and said he had been instructed to defend WikiLeaks’ claim to the material in court if necessary.

The statement said that WikiLeaks is clearly capable of keeping the material secure, and remains in a position to publish it safely.

In his press conference introducing the German-language version of the book here, Domscheit-Berg gave one of the most public airings yet of his side of the dispute that split WikiLeaks’ ranks during the stressful autumn of 2010.

Though his bitterness with WikiLeaks founder Julian Assange – who he describes as formerly his “best friend” – is evident in the book, he displayed a calm, rational front as he discussed the site’s history and impact with author Kuno Haberbusch, and later answered questions.

“I’m not angry today,” he told reporters. Yet he made it clear that the personal and philosophical divide between him and Assange was unbridgeable.

Most important to he and his group of defectors was the issue of transparency, and the ability to establish technological and organizational mechanisms to preserve sources’ anonymity, he said. He briefly described the group’s new project, OpenLeaks, which is being designed as a back-end “service provider” connecting anonymous whistleblowers with media groups and NGOs, and will not play a public WikiLeaks-style role.

Wikileaks’ own protection of sources has come into some question, most prominently with the release of the U.S. diplomatic cables in November. Well before WikiLeaks’ release of the cables, Wired.com reported from chat logs between Army intelligence analyst Bradley Manning and former hacker Adrian Lamo, in which Manning claimed to have provided a quarter-million State Department documents to WikiLeaks. At the time of publication, Manning had already been arrested by the military, and Lamo has provided the logs to the government.

Asked whether Wikileaks had compromised a source by publishing the U.S. diplomatic cables, Domscheit-Berg said it was an issue that “has to be considered.”

“By their publication, the existence of the cables has been established,” he said.

However, he stopped well short of confirming Manning as the source of the diplomatic cables – indeed, he writes in his book that a critical part of WikiLeaks’ security concept was the organization’s own inability to ascertain sources’ identities.  Nevertheless, Domscheit-Berg said the former intelligence analyst, whatever his real role, deserved the strong support of everyone who viewed the leaks as important.

“Just for the sake of (him) having potentially been the source, we all should unite in defending Mr. Manning against prosecution with whatever power we have, and make sure he gets out of this prison,” he said.

Domscheit did not quantify or describe the previously leaked material that is now the subject of WikiLeaks’ legal threats. However, he said it did not include the Bank of America documents Assange has previously promised to release.

He added that he was familiar with some Bank of America material held by WikiLeaks, but that it was “nothing spectacular.” However, Assange might have subsequently received additional information, he cautioned.

Despite WikiLeaks’ current technology problems, Domscheit-Berg was careful to say that the prominent site was not “dead.” It simply had to learn from its experiences, he said. “Maybe this whole story will have a happy ending after all.”