1. Canh Le My 2014.08.11

2.  Motivation  Android app packing  How android execute your application  Available tools  Demonstration 2

3.  Bright side:  How to secure your app  Dark side:  Learn about an application  Modification and its innumerous purposes  Today’s talk. 3

4.  Apk  Jar/Zip file  Contain metadata  Manifest  Certificates  Layouts  Contain code  classes.dex  jars  native libraries  Contain resources/assets 4

5.  /data/app/package-name-.apk 5

6.  Dalvik 6

7.  Smali 7

8.  Apktool  https://code.google.com/p/android-apktool/ https://code.google.com/p/android-apktool/  Apache license 2.0  Decompile and Recompile apk file  Decoding resources to nearly original form (including resources.arsc, XMLs and 9.png files) and rebuilding them.  Baksmali: Classes.dex → smali files  Smali: Classes.dex ← smali files  But smali code is hard to read? 8

9.  Dex2jar  https://code.google.com/p/dex2jar/ https://code.google.com/p/dex2jar/  classes.dex → jar file contains *.class  Decompile tools  jd-gui: not support try-catch, java 5+  jad: no longer maintained  Procyon / Java Decompiler ← the best choice  https://bitbucket.org/mstrobel/procyon https://bitbucket.org/mstrobel/procyon 9

10.  We can use freedom to bypass IAP, but not always success  http://system.in-appstore.com/freedom/ http://system.in-appstore.com/freedom/  Expense Manager 10  https://play.google.com/store/apps/d etails?id=at.markushi.expensemanage r https://play.google.com/store/apps/d etails?id=at.markushi.expensemanage r  Freedom works, but it will lock premium features again after a day.  So, lets see what can we do…

11.  Practice English Grammar 11  https://play.google.com/store/apps/d etails?id=com.testsstore.app.peg0 https://play.google.com/store/apps/d etails?id=com.testsstore.app.peg0  Freedom does NOT work.  So, lets see…

12.  Money Lover 12  https://play.google.com/store/apps/d etails?id=com.testsstore.app.peg0 https://play.google.com/store/apps/d etails?id=com.testsstore.app.peg0  Freedom works perfectly… but you can do a try.

13. Q&A 13

14. THANK YOU! 14