K-12 學校計算機網路/第 9 章

安全基礎

	Technology of Filtering Programs: Blocking Child Pornography on the Internet 

布萊恩·阿普特

Child pornography.  The Internet, a prime source of free, unfettered information, leaves it vulnerable to child pornography, a very small part of what’s available on the Internet that is not readily in public view. Erotic and pornographic information, available on the Internet virtually to everyone, including children, has created a great deal of concern. Because some 20% of children (1 in 5) aged 10 to 17 have been sexually solicited over the Internet, efforts have been made to block child pornography, including the Child Online Protection Act (COPA) (1998) that had been passed and, then, struck down as unconstitutional, most recently July 22 by the U.S. Circuit Court of Appeals in Philadelphia. The federal appeals court, in its ruling, argued that COPA is overly broad and vague and violates the First Amendment because “filtering technologies and other parental control tools offer a less restrictive way to protect children from inappropriate content online.” (Tessler, J., A.P., July 23, 2008, 3A)
What is child pornography?  Child pornography consists of photographs, videotapes, magazines, books, and films that depict children in sexual acts. It is illegal. Although law enforcement has begun to police the Internet, it still relies principally on a vigilant watch of cyberspace to apprehend lawbreakers and on the technology of filtering to block or screen pornography from children using the Internet. 
  But not only schools and families! Businesses are also concerned with the type of Internet materials their workers are assessing over corporate networks. Most companies simply don’t want their workers accessing that material on company time. Some companies now lease the same software parents and schools are buying, and it checks all incoming Internet traffic to every computer in the company on a vigilant watch of cyberspace to apprehend lawbreakers. 

工作場所監控方法：許多公司使用“資料包嗅探器”來跟蹤員工的網際網路行為，這種軟體會檢查或“嗅探”網路上傳輸的每個資料包，並將它們儲存在日誌檔案中。過濾的“嗅探器”只捕獲從指定網站進入網路的資料包。這使技術支援人員能夠檢查檔案並重建網際網路行為。一種更隱蔽的軟體，稱為鍵盤記錄器，會在員工不知情的情況下安裝在他們的電腦上。這種軟體會記錄每次按鍵，並將其記錄下來。兒童網際網路保護法 (CIPA) 及其過濾擴充套件。CIPA 要求接受普遍服務折扣 (USD) 的接收者和接受 ESEA 第三章或圖書館服務資金的接收者必須擁有技術來過濾兒童色情內容和對未成年人有害的材料。然而，地方官員有權為了研究或其他合法目的暫時暫停過濾或遮蔽。網際網路過濾技術：然而，比立法行動更有效的，是網際網路過濾技術——一種軟體，可以讓父母和老師確保他們的孩子不會瀏覽色情內容。一些公司，如 Net Nanny、SurfWatch 和 CyberPatrol，製造和銷售保護軟體，可以監控他們在網際網路上的時間。這些軟體功能強大，易於安裝，可以幫助父母保護孩子。該軟體會檢查網站內容，並禁止孩子訪問不適合他們的網站。一些廣泛用於家庭網路的路由器具有過濾功能，可以遮蔽色情內容、仇恨網站、可疑聊天室和其他網際網路危險。此外，它們與 Google、Yahoo、Alta Vista、Dogpile、Lycos、AllTheWeb 和 MSN 等廣泛使用的搜尋引擎中提供的“安全搜尋”選項合作。當孩子們在全球資訊網上使用搜索引擎進行“僅圖片”搜尋時，他們不會看到指向遮蔽網站的連結，這些網站提供針對色情圖片的保護。過濾可以以多種方式實現：過濾服務。像 AOL 和 MSN 這樣“對兒童友好的”網際網路服務提供商，為他們的客戶提供有效的過濾服務。過濾軟體。一些軟體程式會監控網際網路使用情況，並阻止全球資訊網以及像對等下載網路、聊天室、即時訊息、FTP、論壇和電子郵件等鮮為人知但同樣危險的區域中的令人反感網站。去年夏天（2007 年 7 月）出現了一項打擊兒童色情內容的新戰線。Verizon 和 Time Warner Cable 是美國最大的兩家服務提供商，它們為大約 1600 萬用戶提供服務。此前，紐約州的臥底探員發現網際網路提供商允許兒童色情內容在網上氾濫（但在抵抗和長時間談判之後），它們同意限制對兒童色情內容的訪問，並從伺服器中刪除傳播兒童色情內容的網際網路公告板和網站。他們進一步同意刪除託管在三家公司伺服器上的販賣兒童色情內容的網站。

  New York State developed a new system for identifying child pornography online. Every online picture has a unique “Hash Value” that, once identified and collated, can be used to digitally match the same image wherever it is distributed. By building a library of the Hash values for images identified as child pornography, investigators are able to filter through tens of thousands of online filters at a time, speedily identifying which Internet Service Providers (ISPs) are providing access to child pornography. Investigators, by pursuing Internet service providers, essentially moved beyond the traditional enforcement strategy of confronting the producers of child pornography and their customers. Spearheaded by the National Center for Missing and Exploited Children, these major Internet service providers represent a significant new front on the battle against child pornography.
   Many in the communication industry, arguing that, given the decentralized and largely unmonitored nature of the Internet, they could not be responsible for content online, had previously resisted similar efforts.  But not only that! These companies, plus Sprint, agreed to shut down access to traffic in pornographic images of children on Usenet, one of the oldest outposts of the Internet that, some thirty years ago, was one of the earliest sources of information online. As the World Wide Web continued to flourish, Usenet, essentially supplanted by other search agents, became a favored back alley for traffickers in illicit material. 
  For all of the apparent progress of filtering campaigns against Internet pornography, extended by the goal of making it extremely difficult to find or disseminate pornography online, it is acknowledged that access can not be eliminated entirely. Potential obstacles include third-party companies that sell paid subscriptions that permit consumers to access newsgroups privately, thus preventing even their Internet service providers from tracking their activity. 
  However, for all of its limitations, the process of filtering to prevent child pornography on the Internet has had significant success. For while Internet usage skyrocketed, crimes against children notable declined during the last ten years.

網站限制。有些瀏覽器可以檢查網站中嵌入的特殊評級標籤。有關這些標籤的資訊，請參見網際網路內容評級協會 (ICRA) www.icra.org。這些標籤通常標識一個網站或一個特定頁面的內容描述符。使用者可以將瀏覽器設定為顯示“幻想暴力”但不顯示性內容的頁面。嵌入評級標籤的網站不會顯示，因為瀏覽器無法確保該網站是安全的。這種評級標籤系統並沒有得到廣泛使用，可能有用，但到目前為止，似乎還不是解決網際網路上兒童色情內容問題的普遍解決方案。如何判斷網站是否適合？首先，在內容進入系統時過濾傳入內容。過濾器被程式設計為查詢可能包含“太多肉色”的目標詞語或影像。然而，這種過濾器無法消除有關性教育或乳腺癌的網站。（特里爾，2006 年）此外，雖然過濾器會查詢包含目標詞語的電子郵件，但它可能無法識別“s*e*x”為“sex”。不過，色情垃圾郵件傳送者瞭解常見過濾器的侷限性，並繞過它們。掃描影像很棘手。這就是為什麼儘管內容過濾器經常存在缺陷，但學校別無選擇，只能考慮它們。因為它們可能能夠遮蔽以前未知的惡意網站。

Second method. The second method is based on lists of “good” and “bad” sites. A number of firms that do little but label websites send out regular updates of the “good” and “bad” lists to the subscribers, who may add their sites to the list.
  Search engines are a new area of concern, Google, by using the “cache” option on its  search result page, can allow its users to see websites without having actually to visit the sites. Google keeps copies of web pages on their site. Even after a website has been removed, Google may still be able to display its contents.
  Images are another area of concern. Google permits users to search for images without visiting the site from which the image resides. A student can enter the name of a famous person into a search engine’s image search engine and come up with a listing of nude and seminude images. One protective measure you can take with Google is to turn on its built-in filter called SafeSearch. This setting offers protection both against “adult” images and text.
  Few have the time to look for all the ways to evade the filters—but evidently students do. Which is why there is no effective substitute for simply watching the students. It’s not hard to spot the reaction when students stumble across pornography they should not have found. Hopefully, one can block that website in a short while. In addition, computer-based logging programs can be used to track student activity. If the students have found their way around the filter, the log files will indicate this. Throughout, the age of the student and concerns for privacy should be weighed against the student’s protection. For the protection required for a high school student differs than that for a third grader.  

關於使用過濾程式的爭論在教育界引起了爭議。支援過濾的倡導者認為，過濾器在阻止孩子進入不合適的網站方面做得很好。反對過濾的倡導者認為，過濾軟體會阻止孩子進入包含合適資訊但“不合適”詞語的網站。過濾軟體中使用的“道德指南針”也受到了質疑。人們認為，老師應該能夠教孩子如何避免不合適的網站，而不必讓孩子被過濾軟體鎖在網站之外。有效的組合是過濾系統、教育和警惕。雖然網路自由可能在中等教育中運作良好，但似乎將色情網站納入小學教育存在太大風險。在這些網站上停留片刻就足以增加色情興趣或開始對這種影像脫敏。因此，建議在小學階段採用過濾系統、教學和警惕相結合的方法。教育工作者在場的存在不應該被低估。附近有老師在場，並且對學生在網際網路上搜索的內容積極感興趣，可以有效地阻止不合適的訪問。將電腦放置在房間裡，以便老師能夠始終檢視螢幕內容，也是一個很好的課堂威懾手段。

  Images, we noted above, are also a concern.  Student may enter the name of a famous person into a search engine’s image and retrieve questionable images. One protective measure you can use is to turn on SafeSearch a built-in filter that protects against both “adult” images and texts.
  Although it does not seem that one has the time to search for all the ways around the filters, students seem to find the ways. There is little option, then, but to simply watch the students and quickly block a questionable website. Also, you can also use computer-based log files to keep track of the activities of students. The age of the student and concerns for privacy should be weighed against the student’s right for privacy and protection-- the protection required for a high school student differs from that of a third grader.

PICS。正在處理這個問題的一個組織是網際網路內容選擇平臺 (PICS)，該組織試圖讓父母控制孩子可以訪問的材料型別。PICS 正在努力制定行業標準，用於允許根據網際網路上所有網站和文件的內容對其適合兒童的程度進行評級。此外，該組織還將制定標準，使軟體能夠根據這些適合性評級來遮蔽網站。

   But not only schools and families! Businesses are also concerned with the type of Internet materials their workers assess over corporate networks. Retrieving and displaying sexual material can be interpreted as sexual harassment, and can lead to serious legal ramifications. In addition, most companies don’t want their workers accessing that material on company time. Some companies now lease the same software parents and schools are buying. Instead of installing the software on individual computers, however, the software is installed on a server, which checks all incoming Internet traffic to every computer in the company.

家長控制如何運作。（1）SurfWatch 軟體會檢查每個向 TCP/IP 堆疊傳來的地址的 URL。它會搜尋五種型別的 URL：http、nntp、ftp、gopher 和 IRC——這些 URL 最有可能包含令人反感的內容。它會將每個 URL 放入一個單獨的“盒子”中。它允許其餘傳入的網際網路資料透過。（2）SurfWatch 軟體安裝在父母想要監控的計算機上，以確保孩子無法訪問網際網路上的令人反感的內容。當孩子啟動軟體訪問網際網路時，SurfWatch 會根據使用的是 PC 還是 Macintosh，連線到 Winsock 或 MacTCP。一個 SurfWatch 軟體模組位於 Winsock 或 MacTCP 的“前面”，監控到達 TCP/IP 堆疊的 TCP/IP 資料流。結論。儘管網際網路上的兒童色情內容可能只佔網際網路內容的一小部分，但它對社會構成了巨大挑戰。為了保護兒童免受兒童色情內容的侵害，使用過濾系統是阻止色情內容的有效方法。此外，主要伺服器（如 AOL、Verizon 和 Time Warner）與父母、教育工作者和圖書館員之間的重要合作關係將進一步降低兒童色情內容的發生率。熱線是接收公眾投訴、為執法部門收集情報、從伺服器中刪除非法內容和提供安全教育的一種機制。簡而言之，一項針對色情內容的有效合作關係正在形成。有關家長控制如何運作的摘要，請參見下面第 10 頁的圖示一和二。

  The oval-shaped Surf/Watch module looks for and screens http, nntp, ftp, gopher, IRC, which are most likely to contain objectionable material, from their respective boxes.
 SurfWatch checks thousands of sites and indexes those found to be objectionable. URLs in each of the boxes are checked against those from objectionable sites, blocking the site so that information can’t be viewed. 
 Not only images that offend but offensive words as well!  SurfWatch looking for objectionable words, pattern matching, alerts the child that the site has been blocked, preventing that information from being viewed. 
  In addition, SurfWatch employs a rating system, Platform for Internet Content Selection (PICS), to determine if objectionable material can be found among the documents. Objectionable material is blocked, preventing it from entering the TCP/IP stack. As above, the child is alerted that the site has been blocked.
  If the URL is not found objectionable, it is passed to the TCP/IP stack and then to the Internet software, where the child can view it and interact with it. SurfWatch does the checking instantaneously so there is no apparent delay in getting material from the Internet.
  Because of the furious growth of the Internet, new sites are created frequently. SurfWatch, to keep from being dated, automatically updates the data of sites every month, keeping the list of sites current.
  Businesses, to prevent workers from accessing objectionable sites over corporate networks, have the SurfWatch software installed on a site through which all Internet traffic must travel, filtering Internet traffic for the entire company.

參考文獻 里布爾，邁克，& 貝利，傑拉德 (2007) 學校的數字公民。俄勒岡州尤金：ISTE

特里爾，塞恩·B. (2006) 資金有限的技術：教育工作者和其他專業人士的生存指南。紐約：教師學院出版社。

安全和負責任的網際網路使用中心 http://csriu.org/about

教育工作者針對計算機犯罪和技術濫用的指南 www.uni.uiuc.edu/~dstone/educatorsguide.html

百科全書-維基百科，自由的百科全書

首頁-華夏公益教科書，開放內容教科書的集合。

YouTube 訪談：卡桑德拉·邁達，高階技術培訓師

以企業界為例，這位資深技術培訓師表明，安全是其客戶的主要關注點，但她能夠透過提供一些具體細節並保持積極的態度來減輕他們的擔憂。請記住，如果您試圖向教師和家長推銷您的系統——請保持積極的態度。不要列出所有可能出現的問題（這並不是說服人的有效方法），而要列出您計劃採用的所有解決方案和安全措施。向這位企業培訓師學習，在保持積極和自信的同時解決安全問題。

http://www.youtube.com/watch?v=IQpC53ByRc0

Kmr2136 (talk) 15:09, 10 March 2009 (UTC)

圖表：家長控制如何運作（Gralla，2004，324）

選擇題：1. 過濾系統的核心是：a. Gopher; b. ftp; c. SuperWatch; d. http。2. 最近同意禁止兒童色情的電纜公司：a. ESPN; b. Time Warner; c. Fox; ABC。3. 最有效地阻止兒童在網際網路上觀看色情內容的方法是：a. 有效的過濾系統; b. 立法行動; c. 自願行動; d. 家長指導。4. 谷歌上允許兒童在網際網路上觀看色情內容的工具：a. 搜尋; b. 雅虎; c. AltaVista; d. 快取。

判斷題：1. 由於有效的過濾系統，父母和教師在與兒童色情內容的鬥爭中無需保持警惕。T 或 F 2. 網際網路使用者可能會看到可疑網站，而無需訪問該網站。T 或 F 3. 有效的過濾器被稱為 SafeSearch。T 或 F 4. 對抗兒童色情內容最有效的工具是以下幾種的組合：過濾系統；教育；警惕。T 或 F

選擇題答案

1. 1- b (SurfWatch)
2. 2-b (Time Warner)
3. 3-a (過濾系統)
4. 4-c (快取)

判斷題答案

1. 1-F
2. 2-T
3. 3-T
4. 4-T