企業的資訊安全作法繁多，但不一定能聚焦於最需要之處，以及考慮到成本與時間效益。因此，為企業資訊資產進行分類與建立風險評鑑機制，不僅可以得到資訊資產詳細的風險等級，也可使資訊安全管理決策更精確、完整及有效，避免資訊安全事件的發生。目前國內外有關資訊資產風險評鑑的研究不多，本研究對重視資訊資產管理的銀行業進行研究，以國內某知名銀行為例，由資訊安全管理之作業要點BS 7799-1:2000、資訊安全系統規範BS7799-2:2002和資訊技術安全管理指導綱要ISO/IEC TR 13335做為問卷設計的依據，再以美國國家技術標準局(NIST)於2001年制定的「資訊科技系統風險管理指導」三項程序，進行風險管理。研究中由個案公司的資訊資產清冊中選出十一類24項較可能發生資安事件的資訊資產，使用德菲法進行資料收集分析，評估出資訊資產的相關威脅、弱點及風險等級，同時進行定性與定量的風險分析。研究結果說明個案公司資訊資產風險等級為中等者只有主路由器一項，其餘均為低等級，基於BS 7799-2:2002持續改善的原則，研究中對高風險等級的資訊資產提出建議及改進措施。由於銀行業的資訊環境具有高度雷同性－主要核心業務放在大型主機，外圍由中小型伺服器處理非帳務性系統，且研究個案之規模和資訊系統在銀行業中具有代表性，本研究獲致之成果具實務上的參考價值，可協助企業降低資訊資產風險與資安事件的發生。

Many incidents of information systems result in imperfect protection of information assets. Since overall protection is expensive, even impossible, security measures should be made at the most needed places in terms of cost and time. By means of classification of information assets and their risk assessment, we are able to know the degree of risk of the assets and to achieve a better decision in security measures. Owing to the secrecy policy, research reports on risk assessment of information assets are rarely made public. In this research we classified the information assets of a financial institution and assessed their risks. Because the institution is one of the major banks in Taiwan, the research results should be representative. The Delphi method was adopted in this research and the questionnaires were designed based on the guidelines of information security management of BS 7799-1:2000, BS 7799-2: 2002 and ISO/ IEC TR 13335. In total, 24 information assets subject to security breaches were chosen for risk assessment, and 7 experts in information security and computer auditing were invited to answer the questionnaires concerning current value of the assets, possible threats, vulnerabilities and degree of risks. Risks are expressed in low, medium and high, ranging over 10 degrees on risk scale. The results revealed that there is one item, the core router, with medium risk while others are of low risk. We also made suggestions for enhancing security measures for all assets with risk degree greater or equal to 2. Owing to the lack of publications of researches on classification of information assets and assessment of their risk in financial field, the results achieved in this study is of practical value.