not a valid LUKS device

[J B <bakshi12@gmail.com>]

Hello list,

I want to luks encrypt and new external usb based hard-disk.
So I tried with the command, and it failed with the error as following.

cryptsetup -y --cipher aes-xts-plain --key-size 512 luksFormat /dev/sdc

WARNING!
========
This will overwrite data on /dev/sdc irrevocably.

Are you sure? (Type uppercase yes): YES
Enter LUKS passphrase: 
Verify passphrase: 
Device /dev/sdc is not a valid LUKS device.
Error re-reading LUKS header after update on device /dev/sdc

Any clue ? this is a completely new disk. I have also tried to create partition /dev/sdc1
and executed the command on /dev/sdc1 ..... same error !!!