Way back in the day — back in March of two thousand-naught-eleven, I added a blog post on how to encrypt a partion using crypsetup and luks on RHEL. Its title, ironically enought was, RHEL, How to Encrypt a Partition Using Cryptsetup and Luks.

Today we are going to talk about how to revert an encyrpted partion back to its unencrypted state so that i can use my usb drive normally again.

# cryptsetup status freeagent
/dev/mapper/freeagent is active.
  type:    LUKS1
  cipher:  aes-cbc-essiv:sha256
  keysize: 256 bits
  device:  /dev/sdd1
  offset:  4096 sectors
  size:    2930267906 sectors
  mode:    read/write

First take note of the device name and the name the dev mapper has given the device. The former is /dev/sdd1 and the latter is /dev/mapper/freeagent.

So first lets remove the key file mapping. You will be prompted for your LUKS passphrase

#cryptsetup luksRemoveKey /dev/sdd1
Enter LUKS passphrase to be deleted:

Then lets remove the dev/mapper mapping for /dev/sdd1. Once complete we are free to create a new filesystem on the disk as needed.

#cryptsetup remove /dev/mapper/freeagent /dev/sdd1

Disk Encryption: High-impact Strategies – What You Need to Know: Definitions, Adoptions, Impact, Benefits, Maturity, Vendors