TrueCrypt Cryptanalysis to Include Crowdsourcing Aspect

Organizers of the TrueCrypt audit say they hope to crowdsource some of the cryptanalysis slated for phase two.

TrueCrypt may yet get forked, but it won’t come at the hands of the Open Crypto Audit Project (OCAP), which has a working plan to move forward with a cryptanalysis of the open source encryption software.

OCAP is the brand name for the grassroots movement that arose out of the ashes of the Snowden revelations and concerns about the integrity of TrueCrypt, which has been downloaded close to 30 million times. The first phase of the audit, conducted by iSec Partners examining the TrueCrypt bootloader and kernel driver, found no backdoors; phase two, to begin shortly, will examine the cryptography holding up TrueCrypt.

“I want to be really clear about this: We are considering several scenarios, including potentially supporting a fork, but we’re certainly not doing it before the audit is done,” said Kenneth White, who along with Johns Hopkins professor Matthew Green kickstarted the TrueCrypt audit and OCAP. “We’re not set up to do software development. It’s an important point that we don’t want people to feel like they contributed to an audit and we’re funneling money to a development project.”

OCAP has reportedly raised upwards of $70,000, almost tripling the group’s initial funding goals; and already they’ve pledged to coordinate an audit of OpenSSL, which will be funded by the Linux Foundation under its Core Infrastructure Initiative. A critical vulnerability in OpenSSL was at the center of the Heartbleed storm.

After a bizarre week during which the anonymous TrueCrypt developers cryptically announced that their software was unsafe and development had shut down, the suddenness, uncertainty and mystery of their action kicked off reams of speculation about possible reasons. Were they served with a secret court order for encryption keys, a la Lavabit, and the shutdown was a warrant canary? Was the software hacked beyond repair? Or were they simply 10 years into a project and no longer wanted to pursue such a project in this environment of surveillance and scrutiny?

“The best evidence I’ve seen so far is that it’s what they say on the surface.”

“The best evidence I’ve seen so far is that it’s what they say on the surface: they’ve been at this for 10 years; they started in their late 20s and they’re not interested in doing this anymore,” White said, adding that he tried to reach out to the team through the channels that proved successful last fall when the audit movement began, but to no avail. “As to the criticism about the way they abruptly shut down, all I know is that if your only face to the public is a website and email, and the only verification of trust is a signature key, and all are gone or in question, I’m not clear what remains of the TrueCrypt team anymore.

“I think the community owes them some gratitude for a valiant effort for so many years,” White said.

Despite the massive wrench thrown into the works by last week’s events, phase two of the audit of TrueCrypt 7.1 remains on course, White said. Thomas Ptacek of Matasano Security and Nate Lawson of Root Labs will be the technical leads for phase two; Ptacek will be coordinating and organizing phase two, White said. Efforts to reach Ptacek for comment were unsuccessful; Lawson referred inquiries to White.

White said the next phase of the cryptanalysis, which will include an examination of everything including the random number generators, cipher suites, crypto protocols and more could be wrapped up by the end of the summer. Some of the work, White said, could be crowdsourced following a model used by Matasano, known as the Matasano Crypto Challenges. The now-defunct challenges were a set of more than 40 exercises demonstrating attacks on real-world crypto, exploiting weaknesses in real systems and cryptographic constructions. Those interested in participating emailed Matasano and were sent eight challenges at a time, each stage more difficult than the previous. That same format could be part of the TrueCrypt audit, White said.

“It’s an incredible way for people to identify researchers rising and promising researchers who are not widely known in the community,” White said. “We have top people collaborating and now with the crowdsourcing, I’m excited about it.”

In the meantime, two Swiss men, Thomas Bruderer and Joseph Doekbrijder, have launched, which they said is, for now, a collection point where existing versions of TrueCrypt are available. The site lists four priorities for the effort, including making TrueCrypt available again, and eventually fork TrueCrypt and find funding to continue development of the software.

“Currently the news is still in flux, and we will support any efforts in reviving TrueCrypt,” the two posted on their site, adding that they will not promote anonymous development of TrueCrypt going forward. “If other Initiatives arise we will try to support them. At the moment we want to make sure everyone who wants can continue to use TrueCrypt.”

White, meanwhile, warns curious users that numerous TrueCrypt downloads have popped up since the shutdown, and users should be skeptical.

“We would really urge people to be very careful of anything on SourceForge and any of the download sites that have popped up. We know nothing of their provenance. Trust only curated archives,” White said. “These things make me nervous. It’s an easy avenue for malware.”

This article was updated to include a clarification that the Linux Foundation is funding an audit of OpenSSL.

Suggested articles