Advantage And Disadvantage Advantage l l Reduced Risk

Advantage And Disadvantage Ø Advantage : l l Reduced Risk Reduced Cost Ø Disadvantage : l There are practical limits to the extent that a system can be improved by re-engineering 例子 : 影音聊天室

Software Re-Engineering Ø Process : 1. 2. 3. 4. 5. Source Code Translation (C C++) Reverse Engineering Program Structure Improvement Program Modularization Data Re-Engineering

Re-Engineering Issues Ø The quality of the software to be re- engineered Ø The tool support available for reengineering Ø The extent of data conversion required Ø The availability of expert staff 例子 : Microsoft Window系列

Reverse Engineering Ø Definition l The Process of analyzing software with the objective of recovering its design and specification Ø Help Engineers to understand a program before reorganizing its structure

Realism of Reverse Engineering + Reverse Engineering

在破解中常見的組合語言 Ø CALL -- 呼叫 function Ø JNZ -- jump if not zero Ø JZ -- jump if zero Ø CMP -- 比較

Demo

Reference Ø Heko的破解站 http: //thunder. prohosting. com/~heco/

Merry Christmas and Happy New Year

用Soft. ICE進行破解 Reverse-Engineering 電機四 紀博文

Soft. ICE的畫面

常用HOTKEY Ø F 1 - Help F 5 - RUN F 8 - Trace (into call) F 10 - Trace (not into call) F 12 - RET

Example 2(Winzip 32 v 6. 3) Ø 00409 D 89 call 004096 EA 00409 D 8 E test eax, eax 00409 D 90 jne 00409 DD 3 00409 D 92 call 00409 F 9 C Ø 第 1 行. 那個 call 是一個比較或計算，它將會 設定 eax 成 1 或 0 Ø 第 2 行. test eax, eax 是檢查 eax 是否 0 Ø 第 3 行 如果 eax 是 0 的話，就走到第 4 行那個 call 如果 eax 不是 0 的話，就跳到 00409 DD 3