The leak of a PGP-encrypted email between Ed Snowden's pet journalist Glenn Greenwald and a lawyer has created a bit of a fuss in crypto circles.
Jesselyn Radack, a national security and human rights brief, said an encrypted email sent by her to Greenwald was this week leaked by persons unknown to Cryptome, the long-running online library of leaked documents.
Radack is one of the lawyers representing NSA whistleblower Edward Snowden, something that adds spice to the already heady mix of intrigue.
The content of the email is not particularly sensitive; it references Greenwald's McGill journalism award, and the upcoming Polk media event, neither of which is particularly secret.
Quite how the plaintext of a PGP-encrypted email ended up on a public website has, by contrast, become the focus of interest and speculation. Has someone cracked PGP, some wondered.
One theory, however, is that Radack was tricked into adding a spurious public PGP key to her keyring and then accidentally sent her message not only to Greenwald but to an email address controlled by whoever has the corresponding private key for the mystery public key.
Then, it's claimed, she accidentally encrypted the email for some malicious third-party and sent it to them, allowing the miscreant to decrypt it and leak. It's possible a malware infection was able to help here.
"I have a copy of the full original email and it is encrypted to three keys. Two of them are correct and the third is a likely hostile party," said Tor developer Jacob Applebaum, who has worked with Snowden's dossier dump, in the first of a series of Twitter updates about the leak. "The third key involved is for an email address that may be run by a hostile party, with a PGP key. It is not controlled by Glenn [Greenwald] or Jess [Radack].
"It appears that the person who leaked the PGP encrypted text took out the metadata about a third key, which explains the ability to decrypt," he added.
Applebaum suggests that Cryptome is being manipulated as part of a disinformation campaign. "I think you are actively being played by someone to mess with everyone involved," he told the digital leak site.
Cryptome itself, however, is not altogether convinced about this scenario. It said it remained open to the possibility that some vulnerability involving PGP may somehow be in play, among other possibilities:
Cryptome views the Jacob Appelbaum's information in a message below an allegation similar to the original message. The message he provided could be tampered with as alleged of the original. PGP vulnerabilities are well known among comsec experts but not the public. Comsec experts often conceal vulnerabilities out of self-interest, instead provide misleading information – a practice widespread in most security industries.
A discussion on the issue, featuring various contrasting views as well as the leaked email, can be found here.
US security experts with a patriotic – generally pro-NSA – perspective (such as the th3j35t3r here), along with former NSA staffers (here), were delighted by the whole episode while others took a more neutral stance.
"If this leaked email on Cryptome were from or to me, I'd generate a new PGP key and wipe my computer, pronto," said Christopher Soghoian of the American Civil Liberties Union (ACLU), in an update to his personal Twitter account. ®