恐怖主義是國際公害，其不僅威脅國際社會大多數人的生命、財產安全，也造成局部戰爭和武裝衝突，更使一些國家引發嚴重外交糾紛，造成區域長期動盪不安，直接威脅各國、各個地區乃至全世界的安全與穩定。「911事件」促使全球體認恐怖主義已成為人類和平與安全重大威脅。國際社會對國家安全威脅的防範日益迫切，而加強建立國際合作以防制恐怖主義。 國際恐怖主義活動近來顯現：恐怖活動呈現全球化；恐怖組織呈現跨地區、組織間連結與合作；組織活動更為隱蔽及更難追踪；恐怖份子的經濟實力更強，活動目的更明確；活動手段日趨多樣化；攻擊目標以「軟性對象」為主；攻擊方式以自殺炸彈及汽車炸彈較常見；電腦網路成為恐怖活動的新領域等現象之趨勢。國際恐怖主義活動威脅整體表現在，恐怖活動國際化、多樣化、廣泛化、隱形化、殘酷化、網絡化等態勢。 美國反恐怖主義政策，「911事件」後係以「全球為中心」。反恐政策思維三階段為，先確立「反恐畫線」的外交政策、 再以「邪惡軸心」論為標誌；後提出「先發制人戰略理論。反恐現為美國維護國家安全之最高戰略目標，指導反恐戰略的四項長期政策原則係：不對恐怖主義份子作任何妥協，交換任何條件；恐怖主義份子將為犯下的罪行被繩之以法；孤立支持恐怖主義的國家，並對其施加壓力，迫使其改弦易轍；幫助同美國合作的國家，提高其反恐怖主義的能力。 國際上目前進行國際合作反恐，雖多數國家的反恐作為有所不同，但原則已漸趨一致。反恐行動之目標，概歸為四個重點，即第一、終結國家對恐怖主義之支持；第二、建立與維持一種打擊恐怖主義之負責任的國際標準，以確認地方性之努力、提供行為之評估基礎、擴大資訊交流及持續追尋互惠政策；第三、強化與維持打擊恐怖主義之國際努力，第四、制止與破壞對恐怖主義之物質的支援等，特別是關於大規模毀滅性武器與飛彈擴散等方面。 台灣雖未受國際恐怖主義及其活動之荼毒，但不能忽視當前國際恐怖主義所可能產生之「暗示性」、「示範性」、「傳染性」作用。證諸台灣社會陸續發生仿效性之恐怖主義暴力行為事件，雖不能歸屬於恐怖份子，但其類似引起恐慌之手法，殊值國人關切重視。審視後911事件時期台灣的國家安全處境，政府針對國際合作反恐最新情勢發展，應在參與國際關係、及國土安全反恐作為方面，採取必要應對之政策措施，以確保國家利益與安全。

「九一一」事件後歐盟採取多項反恐措施，包括加強制定反恐法令、強化各項安全維護工作、打擊恐怖組織的財源與連絡管道，以及加強國際反恐合作等，另方面亦開始檢討伊斯蘭社群在當地社會的適應與融入問題，期能多管齊下，減低恐怖活動對歐洲地區的安全危害。本篇論文研究發現，「九一一」事件後歐洲地區的恐怖活動受到激進伊斯蘭思想之滲透影響，與傳統上歐洲地區以分離主義為主的恐怖活動在本質上已有所不同，因此歐盟的反恐作為也必須隨之調整，以因應新型態的恐怖威脅；惟歐盟在多年努力下雖已取得初步反恐成果，但過程中亦面臨部份措施引發爭議及各歐盟成員國之間的協調問題，在與美國等西方國家的國際反恐合作上亦非完全一致，以致未來仍需持續調整其反恐政策作為，俾更有效消弭其面臨之恐怖主義安全威脅。 / EU has adopted several counter-terrorism measures since the 911 terrorist attacks in 2001, with the aim to reduce the terrorist threats in Europe. In this thesis, the author argues that the nature of terrorist activities in Europe has changed from mainly ‘separatism’ before the 911 to ‘Islamic radicalism’ after that. In order to better cope with the new type of terrorist threats, EU has to adjust its counter-terrorism strategies and policies accordingly. However, although EU has garnered some fruits after years of sweat, it is still facing challenges of public criticism and disagreements among EU members as well as the allies across the Atlantic Ocean. In other words, more efforts are needed if the ultimate security and peace is to be acquired in Europe.

網路恐怖主義（Cyberterrorism）為「網際網路」（Internet）與「恐怖主義」（terrorism）相互結合之產物，指恐怖份子為求引發嚴重破壞，並造成平民死傷，透過網際網路入侵國家關鍵基礎設施（critical infrastructures），並以之要脅政府或人民完成其政治性、宗教性或社會性目標。至2012年7月為止，對於網路恐怖主義相關議題之討論雖已持續約30年之久，然而各界對於網路恐怖主義之「定義」及「威脅性」兩項基本問題，仍然眾說紛紜，無法取得一致共識，而全球各地缺乏網路恐怖攻擊之實際案例之情況，亦使爭辯益加激烈。 　　在美國政府方面，經過2001年911事件的重大衝擊，其對於恐怖主義相關議題之敏感程度已大幅提高，並陸續制定多項反恐政策。美國是當前國際反恐行動的領導者，既為軍事與科技大國，同時也是諸多國際恐怖組織策劃攻擊之主要目標，有鑑於此，美國政府致力於防治網路恐怖主義，保護國內關鍵基礎設施不受侵襲，以維持社會安定及國家安全，其因應方式足以成為世界各國制定類似政策之重要參考對象。 　　本論文經由探討網路恐怖主義之基本意涵，比較「網路恐怖主義」、「網路犯罪」及「網路戰爭」三個概念之間的差異，嘗試針對網路恐怖主義形成明確之界定；接著綜整各界針對網路恐怖主義威脅性之爭論，以了解網路恐怖主義之真實威脅程度；最後觀察美國自柯林頓（Clinton）政府至今，有關防治網路恐怖主義政策之一系列發展、美國政府如何評估網路恐怖主義之威脅，以及在當前的政策架構之下，為保護國內關鍵基礎設施，其相對應之具體措施為何，試圖對於其整體政策建立客觀評價。 / Cyberterrorism, the convergence of “Internet” and “terrorism,” refers to the specific terrorist activities that were intended to cause massive destruction and casualties, proceeded by intruding the supervisory control and data acquisition (SCADA) systems of national critical infrastructures via the Internet. Even though the discussion of the related issues of Cyberterrorism has continued for nearly 30 years now, neither the definition nor the evaluation of potential threat concerning Cyberterrorism has been settled. No consensus has been achieved. Furthermore, the lack of actual cases of Cyberterrorism attack around the world makes the debates even more intense. After the significant impact of September 11, 2001, the U.S. government has substantially raised the degree of sensitivity of the issues related to terrorism and developed a number of counter-terrorism policies. As the leader of the Global War on Terror and the greatest Power in the world, the U.S. is also the main target of many terrorist groups. With its military and scientific capabilities, the practices of the U.S. government on preventing Cyberterrorism, protecting its domestic critical infrastructures from intrusion, and maintaining social stability and national security would be excellent examples to other nations for the development of their own policies. To clarify the explicit definition of Cyberterrorism, this research refined the basic meaning of Cyberterrorism and distinguished differences among three related concepts: Cyberterrorism, Cybercrime, and Cyberwar. Moreover, this research sought to induct major arguments brought up by scholars in many intense debates on the extent of Cyberterrorism threat. Last but not least, by observing development of the U.S. related policy frameworks, how the U.S. government evaluates the extent of Cyberterrorism threat, and the corresponding measures for protecting the U.S. domestic critical infrastructures, this research presented an objective assessment on the U.S. overall counter-Cyberterrorism policies.

本論文以近年歐盟會員國境內之孤狼恐怖攻擊趨勢出發，分析歐盟因應孤狼恐怖主義威脅所制定之反恐政策，同時評估歐盟反恐政策之內外反恐成效，藉此檢視孤狼恐怖主義與歐盟反恐政策之因果關係。孤狼恐怖主義緣起於美國「無領袖反抗運動」與「暴力激進化」，並透過「全球伊斯蘭反抗運動」與「外國恐怖主義戰士」成為歐盟內部安全之威脅來源；而歐盟反恐政策之決策機構與執行機關，業已透過戰略方針與行動計畫等歐盟反恐法律文件，對內建立合作機制與輔助工具等內部反恐網絡，藉此強化歐盟與歐盟會員國之間的警察合作、司法合作、資訊與情報交換合作、以及邊境安全合作；對外則透過國際協定形式，與重要第三國以及國際組織建構外部反恐網絡，以雙邊與多邊反恐合作形式強化歐盟反恐能量。本論文亦以四起孤狼恐怖攻擊個案分析歐盟會員國層級之反恐措施，分析近年歐盟孤狼恐怖主義之現況與趨勢。 本論文發現，歐盟孤狼恐怖主義來自「聖戰恐怖主義」、「本土恐怖主義」、與「外國恐怖主義戰士」等三種威脅，而歐盟近年因應孤狼恐怖主義威脅之反恐政策與措施，已朝向2005年11月30日歐盟部長理事會《歐盟反恐政策》四大反恐戰略的「預防」層面發展，並以外國恐怖主義戰士為重要反恐目標；此外，歐盟除了著手打擊「激進化」與「暴力極端主義」等導致孤狼恐怖主義之根本原因原因外，亦持續因應敘利亞與伊拉克等衝突地區之「返國外國恐怖主義戰士」所帶來的後伊斯蘭國時代孤狼恐怖主義威脅。 / With the trend of lone-wolf terrorism in member states of the European Union, the thesis analyzes EU’s policy to counter threat from lone-wolf terrorism and also evaluates internal and external effectiveness of EU’s counter-terrorism policy, in an attempt to examine the correlation between lone-wolf terrorism and EU’s counter-terrorism policy. Lone-wolf terrorism originated in the United States from the “Leaderless Resistance” and “Violent Extremism” and further threatened EU’s internal security via “Global Islamic Resistance Movement” and “Foreign Terrorist Fighters.” The decision-making as well as the executing agencies of EU’s counter-terrorism policy has established mechanisms of cooperation and policy toolkits for internal counter-terrorism network by means of EU’s legal documents of counter-terrorism, strategic guidelines and implementing programs included, in order to consolidate cooperation of police, justice, exchange of communication and intelligence, as well as border security between EU and member states. Meanwhile, EU has also been constructing its external counter-terrorism network with bilateral and multilateral agreements with third states and international organizations of importance. The thesis also offers four case studies of lone-wolf terrorist attacks of EU’s member states to analyze conditions and trends of lone-wolf terrorism in EU. The thesis concludes that “Jihadist terrorism,” “Home-grown Terrorism,” and “Foreign Terrorist Fighters” are the three main types of threat of lone-wolf terrorism in EU, and that EU counter-terrorism policy has been developing strategy of “prevention”, one of which stated in “EU’s Counter-terrorism Strategies” of November 30th, 2005, by Council of the European Union, and considering foreign terrorist fighters as its main target. Additionally, EU has been countering not only root causes of lone-wolf terrorism, such as “radicalisation” and “violent extremism,” but also future threats from “Returning Foreign Terrorists Fighters” heading back home from Syria and Iraq in the Era of Post-Islamic State.