How do I use the vdc cryptfs command correctly?

It seems that the vdc command is not very well documented.

FP2:/ # vdc cryptfs verifypw asdf
200 16036 1

If I try to check an existing password, I can enter any one, it always returns 200.

And without knowing it, it’s pretty risky to change a password like that.

FP2:/ # vdc cryptfs changepw password newpassword

The password change must be verifiable before restarting.

I am grateful for links to documentation or source code. I am also happy about feedback and experience.

That’s why I asked: strong passphrase to start the phone; simpler PIN to unlock for daily use. I know the SnoopSnitch app, but I don’t really trust it as it’s older.


Hello maba007,

Did you have any input already about using these commands on the Fairphone? Actually, I have tried to use them, but on my FPOS 18.10.0 doesn’t seem to have that implemented. It always responds:
/system/bin/sh: vdc: not found


I haven’t received any input yet. But I’ll share my research as soon as I’ve put it together.
You must be root to run the vdc command.

@Phant: Now I’ve taken the time to test and document that.


Thanks for the tutorial. It works here on Fairphone Open 18.10.0.

One suggestion to improve the instructions:
It would be good to mention that this is done via an USB connection to the phone using the adb command on the PC. I’ve first tried it with a terminal app on the Fairphone itself. This did not work because the vdc command was not found (see above).

@Phant Thanks for your feedback, I’ll updated the instructions.

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