---
title: Lab Meeting Minutes 2023/12/08
tags: lab_meeting
---
> Outline
> [TOC]
---
# PERAL Lab Meeting
- 時間：112 年 12 月 08 日 20:00
- 地點：線上
- 線上會議連結 : [Online](https://meet.google.com/zfi-zmnc-qfw)
- 出席者：吳坤熹老師、謝萬霖、劉怡君(請假)、田蕙瑜(請假)、沈家正、梁宇騰、紀見如(缺席)、劉冠伶、林大智(請假)、繆亭霄、蘇翊荃、陳嘉璐(請假)、陳品妤、陳姿綾、陳姿澖(請假)

- 會議主題：[CSCI Rehearsal]()
- 主講者: 繆亭霄、陳品妤
- 主記: 陳姿綾

## 會議內容
### VoIP Steganography using iLBC Start State Residuals


















### An Improved Time-Based Encryption Key Rotation Scheme for Healthcare Databases























---

### 建議&問題(VoIP Steganography using iLBC Start State Residuals)
1. [name=Edgar] Could you briefly introduce the difference between the fixed codebook and the dynamic codebook? And how the dynamic codebook impacts to your hiding capacity?
Ans: [name=August] We didn't modify the codebook of the iLBC codec. We use the default. And the choice of the codebook doesn't bother our method.
2. [name=Ryan] P16, What factors affect the value of PESQ? Latency, quality or something else?
Ans: [name=August] Yes
3. [name=Selena] If I hide more information than the maximum amount of information that can be hidden, will the sound be delayed or will there be changes in timbre?
Ans:[name=August] 品質會下降，變的聽不懂，要藏多一點bit就等下一個frame
4. [name=Ashley] If packets are lost during transmission, do you have any compensation method? The picture on page 16 is too small. Maybe you can consider adding another page.
Ans:[name=August] I have no compensation now
5. [name=Ashley] 突然想起，剛剛在播放簡報時的聲音時會跟你的錄音打架，就是同時播放，但這應該不是預期的結果。
6. [name=Jiazheng] You can choose to hide 0 to 58 bits in a frame? Where did the number 57 in P.15 come from?
Ans: [name=August] Yes; it's because there are 57 bits in residual part in a 20ms frame.
[name=Solomon] You can look up more details, including the formula, in our paper.
7. [name=Miller] p18 Can you explain what worst case and normal case mean？
Ans:[name=August] Normal case:sometime you have to modify bit, somtime you don't have to modify bit
Worst case:you have to modify every bit
9. [name=Solomon] Suggestion: dataset abbr. what do they stands for?

### 建議&問題(An Improved Time-Based Encryption Key Rotation Scheme for Healthcare Databases)
1. [name=Selena] Your experimental results prove that AES improves the efficiency and security of encryption key generation, but does it also increase computing resources? Will it be unbearable because the amount of data in the database increases?
Ans: [name=Ellie] only performance one time to generate key, so it doesn't waste resources a lot.
2. [name=Edgar] Why you use the logical-OR operation rather than concatenation to process the input of the hashing function? What's the benefit?
Ans: [name=Ellie] The operator in hash function in algorithm 3 is actually concatenation. The one in algorithm 1 is to seperate the secret and the times the hash function to take place.

3. [name=Ryan] In algorithms 3 and 4, as far as I understand, S represents the key, and the hash value of '(count - i)' serves as the message to be encrypted. However, wouldn't it is suitable to just hash the value '(i)' as the message to be encrypted? Hashing '(count - i)' seems to have no practical utility.
Ans: [name=Ellie]
1. S is message (count - i) is key
2. count is important ,no count then ciphertext has one secret key

4. [name=Ryan] In previous research, you hashed the key $count times. But in this research, you only hash the secret message one time. So doesn't the value count bring no use in this algorithm. So I think the value {i} calculated by step 1 in algorithm 3 is enough to use as key to encrypt S.
4. [name=Ashley] Can you explain AES encryption?
5. [name=Jiazheng] P.9 typo, Efficiency: To **enhence** ...., should be enhance; P.14 flowchart inconsistent use of capital letter
6. [name=Miller] I don't have any questions, just a small suggestion. The tables in p6 can add some horizontal lines to make it easier to read.
Ans:[name=Ellie]

8. [name=Solomon] p.6 ref number of the previous work.
9. [name=Solomon] In P.25 Conclusion: made the efficiency better. Can you present comparison between previous work, and in table format?
10. [name=Solomon] It sounds that your improvement is simply enlarge the variable Count from a 32-bit integer to a 64-bit long long integer, so brute force attacks will take a much longer time. Do you call this a significant contribution?
Ans:[name=Ellie] This is just a design but I think it is great because it take constant time to generate key
12. [name=Solomon] p.25 "is remain" unchanged

## 待追蹤事項
1. [name=Solomon] 1/15 戶外探索
[name=Selena] 實驗室共10人參加
嘉璐,姿綾,姿澖,品妤,翊荃,家正,冠伶,Angela,怡君,世宇
[name=Solomon] 建議1.或1.30開始，請Angela去跟通識中心確認

## 臨時動議
1. RDMA實驗誰負責？(下次討論)
2. 討論段考週12/22 meeting 是否暫停？(下次討論)

---
散會結束時間：21:39