1. DevQuiz
Android
2011/10/01 Open
at Xi for Developer

2. • YAMAZAKI Makoto(twitter: @zaki50)
4988/5000
• Android
•
• StickyShortcut
• ClaudiaVoice for Android
• Java ( )
• GDD 2011 Japan ADK OpenCall

3. DevQuiz
• Google Developer Day 2011 Japan

4. Android
• AIDL Android
AIDL
package com.google.android.apps.gddquiz;
interface IQuizService {
String getCode();
}

5. 1
1.
2.
3. AIDL

6. 1
1.
2.
3. AIDL

7. •
•
•

8. • apk
• smali (dalvik
assembler)
•
Java

9. Step 1 apk
• apk zip
smali
apktool http://goo.gl/5U8U
$ apktool d DevQuiz11Service_r1.apk
I: Baksmaling...
I: Loading resource table...
I: Loaded.
I: Loading resource table from file: /Users/zaki/apktool/framework/1.apk
I: Loaded.
I: Decoding file-resources...
I: Decoding values*/* XMLs...
I: Done.
I: Copying assets and libs...
$ ls DevQuiz11Service_r1
AndroidManifest.xml apktool.yml res smali

10. smali
• Dalvik
.class public Lcom/google/android/apps/gddquiz/gddquiz11service/DevQuiz11Service;
.super Landroid/app/Service;
.method static synthetic a(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
.locals 1
invoke-static {p0, p1}, Lcom/google/android/apps/gddquiz/gddquiz11service/
DevQuiz11Service;->b(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
move-result-object v0
return-object v0
.end method
• http://pallergabor.uw.hu/androidblog/dalvik_opcodes.html

11. Step 2
• ProGuard
• Service
$ cd DevQuiz11Service_r1/smali
$ grep -rl ".super Landroid/app/Service" .
./com/google/android/apps/gddquiz/gddquiz11service/DevQuiz11Service.smali
$ cat DevQuiz11Service.smali
( )
.method private static b(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
.locals 6
( )
const-string v2, "SHA-1"
invoke-static {v2}, Ljava/security/MessageDigest;->getInstance(Ljava/lang/String;)Ljava/security/MessageDigest;
( )

12. Step 2
• DevQuiz11Service#b private
DevQuiz11Service#a
• DevQuiz11Service#a
$ grep -rl DevQuiz11Service .
./gddquiz11service/a.smali
./gddquiz11service/DevQuiz11Service.smali
./gddquiz11service/DevQuiz11ServiceActivity.smali

13. Step 3 Java
•
.method private static b(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
.locals 6
private static String getCode(String googleAccount, String passcode) {
// googleAccount: p0, passcode: p1
// v0 v5
• static
invoke-virtual {p0}, Ljava/lang/String;->trim()Ljava/lang/String;
move-result-object v0
String v0 = googleAccount.trim();
•
const-string v2, "SHA-1"
invoke-static {v2}, Ljava/security/MessageDigest;->getInstance(Ljava/lang/String;)Ljava/security/
MessageDigest;
move-result-object v2
MessageDigest v2 = MessageDigest.getInstance(“SHA-1”);

14. Step 3 Java
•
new-instance v3, Ljava/lang/StringBuilder;
move-result-object v0
invoke-direct {v3, v0}, Ljava/lang/StringBuilder;-><init>(Ljava/lang/String;)V
StringBuilder v3 = new StringBuilder(v0);
•
if-lt v2, v3, :cond_0
if (v2 < v3) goto cond_0; // goto
if-ne v3, v4, :cond_1
if (v3 != v4) goto cond_1; // goto
• xor
xor-int/2addr v3, v4
v3 ^= v4;

15. Step 3 Java
• → http://goo.gl/78W6s
CodeGenerator.java

16. Step 4

17. • apktook
http://goo.gl/5U8U
• Dalvik opcodes
http://goo.gl/yUX3S
• JUMPERZ.NET Blog: Android
http://goo.gl/aVL3q
• CodeGenerator.java http://goo.gl/78W6s