android encryption: too little time?

Question

I have a 3rd Gen Moto G that I just enabled encryption on. It showed the warning as usual, "make sure it's plugged in, this will take an hour or more", etc. However, after confirming this, the phone rebooted itself, asked me for my pin so it could "boot android" (even though the boot splash screen had already displayed), and then showed me my home screen.

The issue: this whole process took less than a minute. Now, granted, the phone has only 3 lightweight apps on it (aside from the not-very-bloatware-like stuff motorola put on there), plus android standard things. There's also a few albums of music on the 32GB SD card; perhaps under 2GbB.

Less than a minute is not an hour or more. Did the encryption actually happen? The device THINKS it is encrypted; it tells me so in the settings menu. If not, what next steps should I take?

This is android 5.1.1.

I just came across this right before I posted: Device encryption fails, but no error

My device IS plugged into a computer, but through a power-only cable. There is no data connection. Not sure if that matters; I'm not sure I can do anything about it anyway, because the phone says it is encrypted already.

Thanks!

Answer 1

Android encryption is of two types:

1. Device Encryption
2. SD-card Encryption.

For Device encryption kernel DmCrypt layer is used and it encrypts "/data" part of the device.dm-crypt is a transparent disk encryption subsystem in Linux kernel versions 2.6 and later and in DragonFly BSD. (see https://en.wikipedia.org/wiki/Dm-crypt).

Prior to android Lollipop, android device encryption encrypts full "/data" partition. (Encryption is basically a mapping system , it maps all memory from real "/data" block to a virtual block device).

Prior to Lollipop, on some devices(like samsung devices) fast encryption was also supported. Fast encryption means it will encrypt only used partition of your "/data" partition. (i.e. it will map only used parttion). If you will copy any data after encryption, it will be encrypted on runtime and saved on the device.

From Lollipop, google uses default fast-encryption. that means , whenever you will trigger encryption, it will encrypt only your used "/data" partition.

You have mentioned that phone was almost blank, hence it was completed within one minute.

AFAIK google has also changed its encryption system in lollipop and it is much faster than kitkat.

Check this link for more information: https://source.android.com/devices/tech/security/encryption/

You can enter your SD-card on other device and check your files ( these will not be encrypted).If these were encrypted, you will not be able to play on different device.