The NSA revelations shattered earlier assumptions that internet data was nearly impossible to intercept for meaningful surveillance, said Joseph Lorenzo Hall, chief technologist at the Washington-based civil-liberties group Center for Democracy & Technology. That was because any given internet message gets split into a multitude of tiny "packets," each of which traces its own unpredictable route across the network to its destination.
The realization that spy agencies had figured out that problem spurred efforts to better shield data as it transits the internet. A few services such as Facebook's WhatsApp followed the earlier example of Apple's iMessage and took the extra step of encrypting data in ways even the companies couldn't unscramble, a method called end-to-end encryption.
CHALLENGES FOR AUTHORITIES
In the past, spy agencies like the CIA could have hacked servers at WhatsApp or similar services to see what people were saying. End-to-end encryption, though, makes that prohibitively difficult. So the CIA has to resort to tapping individual phones and intercepting data before it is encrypted or after it's decoded.
It's much like the old days when "they would have broken into a house to plant a microphone," said Steven Bellovin, a Columbia University professor who has long studied cybersecurity issues.
Cindy Cohn, executive director for Electronic Frontier Foundation, a group focused on online privacy, likened the CIA's approach to "fishing with a line and pole rather than fishing with a driftnet."
Encryption has grown so strong that even the FBI had to seek Apple's help last year in cracking the locked iPhone used by one of the San Bernardino attackers. Apple resisted what it considered an intrusive request, and the FBI ultimately broke into the phone by turning to an unidentified party for a hacking tool — presumably one similar to those the CIA allegedly had at its disposal.
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