關鍵術語與定義 (Clause 3)
ISO 21434 的 Clause 3 是規範性術語，與 ISO 26262 Part 1 同等重要。
考試會直接測「下列哪個定義最符合 ISO 21434 對 XXX 的定義」。
1. 核心：資安 (Cybersecurity)
Cybersecurity: condition in which assets are sufficiently protected against threat scenarios to items of road vehicles, their functions and their electrical or electronic components.
關鍵字：
- assets：被保護對象
- sufficient：相對概念（依風險決定）
- threat scenarios：威脅情境
- items / functions / E/E components：範圍三層
2. Asset（資產）
object that has value, or contributes to value.
特徵：
- 可以是 資料（韌體、金鑰、PII）、功能（煞車控制）、通訊（CAN 訊號）。
- 評估其 資安屬性 (cybersecurity properties)：CIA + Authenticity + Non-repudiation + Authorization。
3. 威脅情境 (Threat Scenario)
potential cause of compromise of cybersecurity properties of one or more assets in order to realize a damage scenario.
結構：
Threat Scenario = (Asset + 破壞屬性) + 達成方式
→ 對應 12-TARA-Methods/03-Threat-Scenario
4. Damage Scenario（損害情境）
adverse consequence involving a vehicle or vehicle function and affecting a road user.
關鍵：站在 road user (道路使用者) 角度描述「不希望發生的後果」。
- 例：「煞車失靈導致車輛撞擊」是 Damage Scenario。
- 例：「攻擊者注入偽造煞車 CAN 訊號」是 Threat Scenario（不是 Damage）。
Damage = 結果；Threat = 過程。命題單位最愛測這個。
5. Item（標的）
component or set of components that implements a function at the vehicle level, to which ISO 21434 is applied.
重點：
- 與 ISO 26262 的 Item 概念相同，但獨立評估。
- 通常是「車輛級可辨識的功能單元」：TCU、ADAS 控制器、Gateway。
6. Component（元件）
part that is logically and technically separable.
階層：
Vehicle → Item → System → Component → HW/SW Unit
7. CSMS — Cybersecurity Management System
systematic risk-based approach defining organizational processes, responsibilities and governance to treat risk associated with cyber threats.
關鍵字：
- systematic + risk-based
- 組織級而非專案級
→ 02-Organizational-Management/01-CSMS-Overview
8. Cybersecurity Case
structured argument, supported by evidence, providing a compelling, comprehensible and valid case that cybersecurity goals are satisfied.
結構三要素：
- Structured argument：論證邏輯
- Evidence：證據（測試、TARA、Review）
- Claim：要證明的事（資安目標達成）
→ 03-Project-Dependent/06-Case-and-Assessment
9. Cybersecurity Goal
concept-level cybersecurity requirement associated with one or more threat scenarios.
特徵：
- 概念層級（high-level）
- 對應 威脅情境
- 表達為「資安屬性的保護目標」
→ 06-Concept-Phase/02-Cybersecurity-Goals
10. Cybersecurity Claim
statement specifying the cybersecurity-related assumption or sharing of risk.
用途：當你不在 item 範圍內處理某風險時，明確聲明：
- 「這個風險假設由 OEM 處理（不是 Tier-1）」
- 「這個風險由使用者承擔（如 OBD 物理保護）」
→ 06-Concept-Phase/03-Cybersecurity-Claims
11. CIA — Cybersecurity Interface Agreement
agreement between customer and supplier specifying the cybersecurity-related interactions, responsibilities and work products.
內容必包含：
- 雙方角色 (RASIC)
- 共享 Work Product
- 介面點（哪些活動需要哪一方參與）
- 變更管理
→ 04-Distributed-CS-Activities/02-Cybersecurity-Interface-Agreement
12. TARA — Threat Analysis and Risk Assessment
systematic approach to identify and assess cybersecurity-related risks.
八步驟：見 12-TARA-Methods/01-TARA-Overview
13. CAL — Cybersecurity Assurance Level
level that specifies rigor of cybersecurity activities and provides assurance that residual cybersecurity risk is acceptable.
等級：CAL 1 ~ CAL 4（4 最嚴格）
屬性：informative（Annex E）
→ 13-Annexes-Tools/01-CAL-Cybersecurity-Assurance-Level
14. Attack Path / Attack Feasibility
| 術語 | 定義 |
|---|---|
| Attack Path | sequence of deliberate actions to realize a threat scenario |
| Attack Feasibility | attribute that describes the ease of successfully carrying out an attack path |
→ 12-TARA-Methods/05-Attack-Path-Analysis、12-TARA-Methods/06-Attack-Feasibility-Rating
15. Vulnerability / Weakness
| 術語 | 定義 | 差別 |
|---|---|---|
| Weakness | flaw, defect or pre-condition that can develop into a vulnerability | 潛在問題（尚未確認可利用） |
| Vulnerability | weakness that can be exploited as part of an attack path | 可利用的弱點 |
Weakness ⊃ Vulnerability。所有 Vulnerability 都是 Weakness，但反之不必然。
→ 05-Continual-Cybersecurity/03-Vulnerability-Analysis
16. Cybersecurity Incident vs. Event
| 術語 | 定義 |
|---|---|
| Cybersecurity Event | identifiable occurrence in a system that has potential cybersecurity implications |
| Cybersecurity Incident | event that affects the cybersecurity of an item or component |
關係：Event 是廣義發生；經過評估後若確認影響資安，升級為 Incident。
→ 10-Operations-Maintenance/01-Incident-Response
17. Item Definition / Operational Environment
| 術語 | 重點 |
|---|---|
| Item Definition | 描述 item 的範圍、邊界、功能、介面、依賴 |
| Operational Environment | item 運行的環境條件（含實體、邏輯、時間） |
→ 06-Concept-Phase/01-Item-Definition
18. Residual Risk（殘餘風險）
remaining cybersecurity risk after risk treatment.
- 必須被明確接受 (accepted) 並文件化。
- 接受人需有適當權責層級。
- 構成 Cybersecurity Case 的一部分。
→ 12-TARA-Methods/08-Risk-Treatment
19. EoS — End of Cybersecurity Support
point in time after which cybersecurity support for a product is no longer provided.
關鍵：
- 必須事先通知相關方（如車主、OEM）。
- 不等於車輛除役；EoS 後車輛仍可運作但不再修補弱點。
→ 11-EndOfSupport-Decommission/01-End-of-Support
20. Decommissioning（除役）
permanent retirement of a cybersecurity-relevant component or item.
特徵：
- 含資料清除（金鑰、PII、訓練資料）。
- 含憑證撤銷 (V2X PKI)。
- 不可逆。
→ 11-EndOfSupport-Decommission/02-Decommissioning
速記表
| 縮寫 | 全名 | 中文 |
|---|---|---|
| CSMS | Cybersecurity Management System | 資安管理系統 |
| CS | Cybersecurity | 資安 |
| CIA | Cybersecurity Interface Agreement | 資安界面協議 |
| CIA-AAA | Confidentiality/Integrity/Availability/Authenticity/Authorization/Auditability | 資安屬性 |
| TARA | Threat Analysis and Risk Assessment | 威脅分析與風險評估 |
| CAL | Cybersecurity Assurance Level | 資安保證等級 |
| SFOP | Safety / Financial / Operational / Privacy | 衝擊類別 |
| OTS | Off-The-Shelf | 既有元件 |
| RFQ | Request For Quotation | 詢價單 |
| WP | Work Product | 工作產物 |
| EoS | End of Cybersecurity Support | 終止資安支援 |
| RASIC | Responsible/Accountable/Supporting/Informed/Consulted | 角色矩陣 |
Related Notes
- 01-Foundations/01-Standard-Overview
- 01-Foundations/03-Cybersecurity-vs-Safety
- 12-TARA-Methods/01-TARA-Overview