I'm probably just inviting myself to get trolled by replying to this, but this comment is just ridiculously wrong on so many levels.
> The fact that the guy behind it is hyping it via the New York Times, a generalist publication, instead of validating the thing through professional cryptographers (which he isn't) and recognised privacy champions such as the EFF is very telling.
Cryptographer Matthew Green on Signal's crypto and code quality (it was called RedPhone/TextSecure at the time of this writing): https://blog.cryptographyengineering.com/2013/03/09/here-com...
Version 1.0 of EFF's Secure Messaging Scorecard gave Signal 7/7: https://www.eff.org/node/82654.
> The thing has not been properly validated or verified (for a start, because there is no design document to validate against, and no published goals to verify against)
Signal has been analyzed, with favorable results, by academic researchers at least twice:
> it uses an ad-hoc encryption scheme from a non-cryptographer
Moxie Marlinspike and Trevor Perrin probably wouldn't call themselves "cryptographers," but almost anybody in the field would agree that they are experts on applied cryptography.