網路電話（VoIP）具有高隱匿性、移動性、低成本性，目前已經成為詐騙集團最佳 的犯罪工具之一，本文首先探討網路電話的安全威脅，再針對所有的威脅逐一分析，研 究出各種威脅的因應之道，並提出網路電話數位證據鑑識標準作業程序，來解決數位證 據易修改的問題，以確保原始資料及所擷取的證據之完整性。最後進行網路電話數位證 據鑑識機制的驗證，以供鑑識資通犯罪人員提供未來偵查的原則、方向和準則。

The development of the Internet is fuelled by numerous commercial intentions; it is no longer simple information delivery. Moreover, many criminals try to earn profit through the Internet. Thus, the use of the internet should be under the protection of information security in order to assure honest users. The main problems today include Internet phone fraud and internet phone attacks; therefore, in addition to the analysis and management of Internet security vulnerabilities, penetration testing should be added to test the security in a practical Internet environment. This paper consults the related works of DEFSOP and correlative digital evidence from different scholars and develops a higher quality and more suitable DEFSOP. In addition, this paper discusses the security problems faced by the VoIP, lists prevention policies and designs a VoIP DEFSOP to help forensics operators. This paper shows how VoIP DEFSOP works in the operation stage through experiments in order to provide investigators with suggestions for the future.