ChaCha8/12/20 and GEOM ELI tests

[Adam Nowacki]

On 2015-01-14 19:44, rozhuk.im at gmail.com wrote:
>> Excuse me, but if you think your physical medium is either 100%
>> inaccessible to an adversary, or simply not worth a real attack, and
>> the speed is the concern, then why do you want to use any encryption at
>> all?
> 
> 100% is not available yet introduced GELI keys / mounted drive.
> AES-XTS is good but too slow.

FreeBSD supports AES-NI - hardware accelerated AES available in many
Intel and AMD processors. I'm seeing speeds of 1GB/s on i5 2500K.

> ChaCha is already enough to cryptography was not a bottleneck.
> 
> The case when the disks - local (SATA/SAS/IDE/USB), keys entered / disk is mounted and the attacker has access I do not see because AES-XTS does not help.

A few scenarios that will break ChaCha encryption:
- remapped bad sectors on spinning disks,
- multiple copies of sectors on SSD due to wear leveling,
- RAID with one of the drives dropping out due to bad cabling, bad
sectors or other issues,
- disk imaged at multiple points in time (for example powered-off laptop
left unattended).