Feds put heat on Web firms for master encryption keys:
If the government obtains a company's master encryption key, agents could decrypt the contents of communications intercepted through a wiretap or by invoking the potent surveillance authorities of the Foreign Intelligence Surveillance Act. Web encryption -- which often appears in a browser with a HTTPS lock icon when enabled -- uses a technique called SSL, or Secure Sockets Layer.
"The government is definitely demanding SSL keys from providers," said one person who has responded to government attempts to obtain encryption keys. The source spoke with CNET on condition of anonymity.
The person said that large Internet companies have resisted the requests on the grounds that they go beyond what the law permits, but voiced concern that smaller companies without well-staffed legal departments might be less willing to put up a fight. "I believe the government is beating up on the little guys," the person said. "The government's view is that anything we can think of, we can compel you to do."
How they do it? probably like this (see wikipedia):
Room 641A is a telecommunication interception facility operated by AT&T for the U.S. National Security Agency that commenced operations in 2003 and was exposed in 2006.
and this:
GCHQ taps fibre-optic cables for secret access to world's communications
British spy agency collects and stores vast quantities of global email messages, Facebook posts, internet histories and calls, and shares them with NSA, latest documents from Edward Snowden reveal