My device is rooted, Android 5.1, but I couldn't find key file previously, so I used this script. It gave several errors and key file wasn't extracted.
=========================================================================
= This script will extract the WhatsApp Key file and DB on Android 4.0+ =
= You DO NOT need root for this to work but you DO need Java installed. =
= If your WhatsApp version is greater than 2.11.431 (most likely), then =
= a legacy version will be installed temporarily in order to get backup =
= permissions. You will NOT lose ANY data and your current version will =
= be restored at the end of the extraction process so try not to panic. =
= Script by: TripCode (Greets to all who visit: XDA Developers Forums). =
= Thanks to: dragomerlin for ABE and to Abinash Bishoyi for being cool. =
= ### Version: v4.7 (12/10/2016) ### =
=========================================================================
Please connect your Android device with USB Debugging enabled:
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
adb server is out of date. killing...
* daemon started successfully *
WhatsApp 2.23.4.79 installed
Downloading legacy WhatsApp 2.11.431 to local folder
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 1942 100 1942 0 0 2762 0 --:--:-- --:--:-- --:--:-- 2762
adb server is out of date. killing...
* daemon started successfully *
Backing up WhatsApp 2.23.4.79
Backup complete
Installing legacy WhatsApp 2.11.431
* daemon not running. starting it now on port 5037 *
ADB server didn't ACK
* failed to start daemon *
error: cannot connect to daemon
adb server is out of date. killing...
* daemon started successfully *
Install complete
adb server is out of date. killing...
* daemon started successfully *
Now unlock your device and confirm the backup operation.
Please enter your backup password (leave blank for none) and press Enter:
Exception in thread "main" java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)
Caused by: java.lang.RuntimeException: java.lang.NumberFormatException: For input string: ""
at org.nick.abe.AndroidBackup.extractAsTar(AndroidBackup.java:420)
at org.nick.abe.Main.main(Main.java:128)
... 5 more
Caused by: java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at org.nick.abe.AndroidBackup.extractAsTar(AndroidBackup.java:280)
... 6 more
bin\tar.exe: Cannot open tmp\whatsapp.tar: No such file or directory
bin\tar.exe: Error is not recoverable: exiting now
bin\tar.exe: Cannot open tmp\whatsapp.tar: No such file or directory
bin\tar.exe: Error is not recoverable: exiting now
bin\tar.exe: Cannot open tmp\whatsapp.tar: No such file or directory
bin\tar.exe: Error is not recoverable: exiting now
bin\tar.exe: Cannot open tmp\whatsapp.tar: No such file or directory
bin\tar.exe: Error is not recoverable: exiting now
bin\tar.exe: Cannot open tmp\whatsapp.tar: No such file or directory
bin\tar.exe: Error is not recoverable: exiting now
Cleaning up temporary files ...
Deleted file - C:\Users\ABC\Desktop\123\WhatsApp-Key-DB-Extractor-master\tmp\whatsapp.ab
Deleted file - C:\Users\ABC\Desktop\123\WhatsApp-Key-DB-Extractor-master\tmp\waplen.txt
Deleted file - C:\Users\ABC\Desktop\123\WhatsApp-Key-DB-Extractor-master\tmp\sdpath.txt
Deleted file - C:\Users\ABC\Desktop\123\WhatsApp-Key-DB-Extractor-master\tmp\wapath.txt
Deleted file - C:\Users\ABC\Desktop\123\WhatsApp-Key-DB-Extractor-master\tmp\wapver.txt
Deleted file - C:\Users\ABC\Desktop\123\WhatsApp-Key-DB-Extractor-master\tmp\sdkver.txt
Done
Restoring WhatsApp 2.23.4.79
adb server is out of date. killing...
* daemon started successfully *
4316 KB/s (11075584 bytes in 2.505s)
adb server is out of date. killing...
* daemon started successfully *
pkg: /data/local/tmp/base.apk
Failure [INSTALL_FAILED_INVALID_APK]
adb server is out of date. killing...
* daemon started successfully *
Restore complete
Removing WhatsApp 2.23.4.79 temporary apk
Deleted file - C:\Users\ABC\Desktop\123\WhatsApp-Key-DB-Extractor-master\tmp\base.apk
Operation complete
Press any key to continue . . .
My device is rooted, Android 5.1, but I couldn't find key file previously, so I used this script. It gave several errors and key file wasn't extracted.