The Internet affords anonymity to its users, a blessing to privacy and freedom of speech. But that very anonymity is also behind the explosion of cyber-crime that has (1)_____ across the Web.

    Can privacy be preserved (2)_____ bringing safety and security to a world that seems increasingly (3)_____?

    Last month, Howard Schmidt, the nation’s cyber-czar, offered the federal government a (4)_____ to make the Web a safer place—a “voluntary trusted identity” system that would be the high-tech (5)_____ of a physical key, a fingerprint and a photo ID card, all rolled (6)_____ one. The system might use a smart identity card, or a digital credential (7)_____ to a specific computer, and would authenticate users at a range of online services.

    The idea is to (8)_____ a federation of private online identity systems. Users could (9)_____ which system to join, and only registered users whose identities have been authenticated could navigate those systems. The approach contrasts with one that would require an Internet driver’s license (10)_____ by the government.

    Google and Microsoft are among companies that already have these “single sign-on” systems that make it possible for users to (11)_____ just once but use many different services.

    (12)_____ , the approach would create a “walled garden” in cyberspace, with safe “neighborhoods” and bright “streetlights” to establish a sense of a (13)_____ community.

    Mr. Schmidt described it as a “voluntary ecosystem” in which “individuals and organizations can complete online transactions with (14)_____, trusting the identities of each other and the identities of the infrastructure (15)_____ which the transaction runs”.

    Still, the administration’s plan has (16)_____ privacy rights activists. Some applaud the approach; others are concerned. It seems clear that such a scheme is an initiative push toward what would (17)_____ be a compulsory Internet “driver’s license” mentality.

    The plan has also been greeted with (18)_____ by some computer security experts, who worry that the “voluntary ecosystem” envisioned by Mr. Schmidt would still leave much of the Internet (19)_____. They argue that all Internet users should be (20)_____ to register and identify themselves, in the same way that drivers must be licensed to drive on public roads.

答案精析：空处所填词是offered（提供）的直接宾语，破折号后“身份自动识别系统”为空处所填词的同位语，to make the Web a safer place（使网络更安全）是offered的目的，从后文可知，该系统的预期效果是实现网络安全，可判断它应该是施密特为政府提出的建议，故D选项为正确答案。

错项排除：原文中“身份识别系统”是使网络环境更安全的手段，并非原因，故A选项错误。B、C选项代入原文语义不通，不符合语境。