Though we have come a long way, the right to privacy — the foundation of the freedoms enshrined in the United States Bill of Rights — remains under threat. Some of the world’s most popular online services have been enlisted as partners in the N.S.A.’s mass surveillance programs, and technology companies are being pressured by governments around the world to work against their customers rather than for them. Billions of cellphone location records are still being intercepted without regard for the guilt or innocence of those affected. We have learned that our government intentionally weakens the fundamental security of the Internet with “back doors” that transform private lives into open books. Metadata revealing the personal associations and interests of ordinary Internet users is still being intercepted and monitored on a scale unprecedented in history: As you read this online, the United States government makes a note.