Critics, including some congressional leaders, say that the role of N.S.A. surveillance in thwarting terrorist attacks — often cited by the agency to justify expanded powers — has been exaggerated. In response to the controversy about its activities after Mr. Snowden’s disclosures, agency officials claimed that the N.S.A.’s sweeping domestic surveillance programs had helped in 54 “terrorist-related activities.” But under growing scrutiny, congressional staff members and other critics say that the use of such figures by defenders of the agency has drastically overstated the value of the domestic surveillance programs in counterterrorism.

Agency leaders believe that the N.S.A. has never enjoyed such a target-rich environment as it does now because of the global explosion of digital information — and they want to make certain that they can dominate “the Sigint battle space” in the future, the document said. To be “optimally effective,” the paper said, “legal, policy and process authorities must be as adaptive and dynamic as the technological and operational advances we seek to exploit.”

Intent on unlocking the secrets of adversaries, the paper underscores the agency’s long-term goal of being able to collect virtually everything available in the digital world. To achieve that objective, the paper suggests that the N.S.A. plans to gain greater access, in a variety of ways, to the infrastructure of the world’s telecommunications networks.

Reports based on other documents previously leaked by Mr. Snowden showed that the N.S.A. has infiltrated the cable links to Google and Yahoo data centers around the world, leading to protests from company executives and a growing backlash against the N.S.A. in Silicon Valley.

Yet the paper also shows how the agency believes it can influence and shape trends in high-tech industries in other ways to suit its needs. One of the agency’s goals is to “continue to invest in the industrial base and drive the state of the art for high performance computing to maintain pre-eminent cryptanalytic capability for the nation.” The paper added that the N.S.A. must seek to “identify new access, collection and exploitation methods by leveraging global business trends in data and communications services.”

And it wants to find ways to combine all of its technical tools to enhance its surveillance powers. The N.S.A. will seek to integrate its “capabilities to reach previously inaccessible targets in support of exploitation, cyberdefense and cyberoperations,” the paper stated.

The agency also intends to improve its access to encrypted communications used by individuals, businesses and foreign governments, the strategy document said. The N.S.A. has already had some success in defeating encryption, The New York Times has reported, but the document makes it clear that countering “ubiquitous, strong, commercial network encryption” is a top priority. The agency plans to fight back against the rise of encryption through relationships with companies that develop encryption tools and through espionage operations. In other countries, the document said, the N.S.A. must also “counter indigenous cryptographic programs by targeting their industrial bases with all available Sigint and Humint” — human intelligence, meaning spies.