Edward Snowden's message to SXSW is that end-to-end encryption is–along with public oversight–a crucial part of ensuring our future privacy.

Many people believe that the N.S.A., if it decides to do so, can crack any encryption method. Soghoian, an expert in online security, said that this was generally true, but he nonetheless agreed with Snowden that the widespread adoption of end-to-end encryption would be a good thing. Breaking encrypted messages takes a lot of time and effort, he explained. If all online messages were encrypted properly, the N.S.A. would find it difficult to monitor large numbers of people. “Encryption makes bulk surveillance too expensive,” Soghoian said. Snowden, for his part, was even more optimistic about the promise of encryption. “The bottom line is that encryption does work,” he said. In support of this argument, he pointed to his own use of secure communications. Since he revealed to the world the inner workings of the N.S.A., the U.S. government has had a huge team trying to track him and his work, he said, but as far as he knew they hadn’t succeeded.

Also relevant to this: How Apple secures your iCloud keychain even from itself.