---
# System prepended metadata

title: '[111/11/09] 續讀 IBE'
tags: [會議記錄]

---

# [111/11/09] 續讀 IBE
###### tags: `會議記錄`


(碩俊) 稍整理: Diffie, Hellman的New Directions in Cryptography
https://hackmd.io/@shuochun/SJ-DaeYBs </br>

1. P48. "The secret keys must be computed by a key generation center rather than by the users" 為什麼User secret key一定要由系統做呢?由使用者自己做對使用者不是更安全嗎?: 這段話主要的意思是指，製作私鑰的演算法、hash function都是公開的，但是必須只能讓系統持有系統私鑰去做使用者私鑰。否則，使用者A就能做出其他人的私鑰。
2. P.48 "The overall security of the scheme dapends on the the following points (a)The security of the underlying cryptographic functions" 關於(a)我們的問題是，到底underlying cryptographic functions是指誰?(b)秘密資訊只有key generation center知道(c)系統在發卡給使用者前會先進行完整、徹底的身分驗證工作(d)預防使用者弄丟卡片、複製卡片、未經授權的使用卡片</br>

> [name=柏盛學長]原始的PKE要是安全的，加上ID作為PK的機制才會是安全的。
> [name=煒甯]c是在指有做了這樣的工作才能達到前述ID對於使用者而言，具備了不可抵賴的特性。
> [name=育靜跟怡榮學姊]未經授權是不在這個組織(跟撤銷相關)使用或是非該卡片持有者使用。
> [name=碩俊]要達成這四點，我們才能稱這個IBE是安全的。

3. Like any other agency that issues ID cards, the center must carefully screen requests for cards to prevent misrepresentations, and must carefully protect its 'stamps' to prevent forgeries. </br>
`stamps是指什麼呢?`
>[name=元瑾]misrepresentation是冒用他人身分；forgery去直接偽造
>[name=史萊哲甯+500分]stamps是指系統私鑰，有它我們才能核發使用者私鑰給使用者。






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