TrueCrypt Audit Stirs Back To Life


The organizers of the TrueCrypt audit expect the cryptanalysis of the open source encryption software to begin shortly; phase two will be handled by NCC Group’s Cryptography Services practice.

The stagnant TrueCrypt audit stirred to life in the last 24 hours with the announcement that the second phase of the audit, tasked with examining the cryptography behind the open source disk encryption software, will begin shortly.

NCC Group’s Cryptography Services has been contracted to do the cryptanalysis of the original TrueCrypt 7.1a version, which is the baseline for newer forks, said Johns Hopkins professor Matthew Green, one of the originators of the movement to have the integrity of the code evaluated.

Questions arose as shrapnel from the Snowden revelations flew in all directions about potential backdoors in widely used software, including TrueCrypt, which has been downloaded close to 30 million times. This coupled with the fact that the authors of TrueCrypt have never been publicly revealed added a sense of urgency to the movement

Green, along with Kenn White, began a grassroots fundraising effort to audit TrueCrypt, and the first phase of the audit was done in relatively short order, examining the TrueCrypt bootloader and Windows kernel driver; architecture and code reviews were performed, as well as penetration tests including fuzzing interfaces. Conducted by iSEC Partners, the first phase of the audit turned up a dozen vulnerabilities and some questions about code quality, but zero backdoors.

The cryptanalysis was supposed to be wrapped up by the fall of 2014, according to original estimates. After the TrueCrypt authors abruptly shut down the project in the spring of 2014, speculation ramped up that perhaps they’d been served a court order to turn over their encryption keys, and rather than comply, they closed up shop as an overt warrant canary. Other speculation was that the project had been hacked and could not continue, or that the authors simply no longer wanted to pursue maintaining the code as more and more surveillance revelations surfaced.

“This threw our plans for a loop,” Green said yesterday in a blog post. Green and White’s Open Crypto Audit Project had raised $70,000 to audit TrueCrypt and they planned to crowdsource the crypto audit and that part of the project was to be coordinated by Thomas Ptacek, formerly of Matasano Security. Green, however, said the authors’ decision to abandon TrueCrypt development forced them in a different direction. Ptacek, for his part, took some of the blame and wrote a post on HackerNews explaining how work on cofounding a new security company and other time constraints caused things to go “off the rails.”

Green said a few weeks back, OCAP signed a contract with NCC Group’s Cryptography Services (a blend of iSEC, Matasano and Intrepidus Group experts) to audit TrueCrypt 7.1a. The start date, Green said, remains flexible as they try to contain costs and stretch donations farther.

“In our copious spare time we’ve also been looking manually at some portions of the code, including the TrueCrypt RNG and other parts of the cryptographic implementation,” Green said. “This will hopefully complement the NCC/iSEC work offer a bit more confidence in the implementation.”

A statement from NCC Group said that it will focus on the most widely used and standardized components: XTS mode used with AES and the Double and Triple Compositions.

“it’s likely we’ll be getting eyes on several other crypto-related portions of the codebase,” NCC Group said. “But these will be the primary focus.”

Green apologized in his post to the project’s donors for the pace of the project.

“This project has been a bit slower than any of us would like, but results are coming,” Green said. “Personally, my hope is that they’ll be completely boring.”

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