Crypt

• Encrypts the data passing through

• Uses the kernel Crypto API

• Parameters are:

  • crypt <cipher> <key> <IV offset> <device> <offset>

• Cipher consists of: cipher-chainmode-ivmode:ivoptions

• Ciphers available are listed in /proc/crypto e.g. aes

• IV is an initial vector used to vary the encryption.

  • plain uses the sector number (plus IV offset) as IV.
  • essiv is an enhancement avoiding a watermark weakness

• Chainmode: always cbc. Don't use ebc – it doesn't use an IV.

• IV mode is plain or essiv:hash

• Key is supplied in hex