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資訊安全期末 Paper 報告 - PowerPoint PPT Presentation

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資訊安全期末Paper報告

Data Hiding on 3D Triangle Meshes

François Cayre and Benoît Macq, Senior Member, IEEE

89321018 藺心皓

1.Introduction

• 近年來由於電腦硬體的發達，間接促成3D技術的普及，因此有人開始將3D圖形的特性應用到Steganography之中。

• TSPS – Triangle Strip Peeling Sequence

1.Introduction (Cont.)

• 因此本篇paper主要提出一種簡易且提高安全性的TSPS修改版

2.Background

• cover- media : 用來遮掩plaintext的東西，在本篇中即為 Triangle-Meshes

• 本篇paper所使用的加密方法 : substitutive

Blind scheme in the spatial domain.

2.Background(cont.)

3. PRESENTATION OF THE PROPOSED ALGORITHM

• TSPS basic idea :

3. PRESENTATION OF THE PROPOSED ALGORITHM　(cont.)

• 基本的演算法，包含兩個步驟：

• 1. 利用Secret Key 找出用來掩蓋payload的Triangle mesh

macro embedding procedure (MEP)

3. PRESENTATION OF THE PROPOSED ALGORITHM　(cont.)

• Part1 : mesh strip的挑選取決於secret key

3. PRESENTATION OF THE PROPOSED ALGORITHM　(cont.)

• Part2.(MEP)

Define :

P 為在空間中垂直於line_AB的平面

4. Binary MEP

4. Binary MEP 　(cont.)

“入k” : C(原本Triangle兩個exit edge所夾的point) 到 P的距離

4. Binary MEP 　(cont.)

5.Moving on the Mesh

1. Avoiding Peeling

2. Admissibility and Upper Bound for Capacity

Data store upper bound = number of points inside the cover mesh

5.Moving on the Mesh(cont.)

• Topological Boundaries: Initial and the Final Cells

Initial Cells : 兩種方法，一是選擇具有某些特性的三角形(面積max or min, etc.)，另一方法則是由Secret key決定。

至於Initial edge則是選長度最大的作為Initial entry edge。

Final Cells : 由secret key決定 (key的長度 = payload data 的長度)

5.Moving on the Mesh(cont.)

• Security

Attacker需要解決的兩個首要的問題：

• Find the initial Cells

• Find the path over the meshes

6. RESULTS AND FUTURE IMPROVEMENTS

Coding speed

&

6. RESULTS AND FUTURE IMPROVEMENTS(cont.)

Distortion

&

MEP order

6. RESULTS AND FUTURE IMPROVEMENTS (cont.)

Processing Time

&