《Operating System Concepts》學習第 58 天，p636-p666 總結，總計 31 頁。

一、技術總結

1.system and network threats

(1)attack network traffic

(2)denial of service

(3)port scanning

2.symmetric/asymmetric encryption algorithm

(1)symmetric encryption algorithm

A cryptography algorithm in which the same keys are used to encrypt and decrypt the message or data.

(2)asymmetric encryption algorithm

A cipher algorithm in which different keys are used for encryption and decryption.

二、英語總結(生詞：3)

1.masquerade

(1)masquerade: maschera("mask") + -ade(suffix that indicating an action or process)

c/u. behavior that is intended to prevent truth from being known(掩飾)；vi. to pretend to be(偽裝)。

(2)示例

Alternatively, an attacker can take a more active role, either masquerading as one of the parties (referred to as spoofing), or becoming a fully active man-in-the-middle, intercepting and possibly modifying transactions between two peers(《Operating System Concepts》第 636 頁)。

2.defense

(1)defend: de-("away, off") + fendere("to strike, hit, push")

vi/vt. defend literally means to push away an attack(to protect from harm，保護，防衛，捍衛).

(2)defense

u. the act of pretect sth against attack。需要注意用法：defense of, defense against。

(3)示例

He published an essay in defense of the freedom of the press(新聞)。

There are many defenses against computer attacks, running the gamut from methodology to technology(《Operating System Concepts》第 637 頁)。

3.ask

(1)be asking for it/trouble(自找麻煩)

However, for applications where security matters, we are asking for trouble if we assume that the source or destination address of a packet reliably determines who sent or received that packet(《Operating System Concepts》第 638 頁)。

關于英語的注解同步更新匯總到 https://github.com/codists/English-In-CS-Books 倉庫。

三、其它

第 16 章(security)簡評：該章節對security領域提綱挈領地的進行了介紹，相對而言較簡單，只是個入門。

四、參考資料

1. 編程

(1) Abraham Silberschatz，Peter Baer Galvin，Greg Gagne《Operating System Concepts》：https://book.douban.com/subject/30272539/

2. 英語

(1) Etymology Dictionary：https://www.etymonline.com

(2) Cambridge Dictionary：https://dictionary.cambridge.org

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