Re: round and round they go, keys in ram are ripe for picking...

[coderman <coderman () gmail com>]

On Thu, Feb 21, 2008 at 12:43 PM, Elazar Broad <elazar () hushmail com> wrote:
> http://blog.wired.com/27bstroke6/2008/02/researchers-dis.html

"Lest We Remember: Cold Boot Attacks on Encryption Keys"

the best part is:
'''
Countermeasures and their Limitations

Memory imaging attacks are difficult to defend against because
cryptographic keys that are in active use
need to be stored somewhere. Our suggested countermeasures focus on
discarding or obscuring encryption keys before an adversary might gain
physical access, preventing memory-dumping software from being
executed on the machine, physically protecting DRAM chips, and
possibly making the contents of memory decay more readily.
'''

executive summary:

- don't let malware read keys from memory.  (ah, security, so many
holes, so many weak links...)

- the ability to scrub keys out of memory is ideal, but likely
fallible.  can you hit that panic button fast enough?

- boot from secure media. you're booting from a read-only iso into
that FDE protected OS, right?

- avoid pre-computation of key schedules. high throughput hardware
crypto implementations are great for this. i love padlock engines...

- key expansion: i'm not familiar with any FDE that does this.  anyone?



note that if you're not using key scrubbing in your disk encryption
(loop-aes?) you've got bigger remanence problems to worry about:

"Data Remanence in Semiconductor Devices"
http://www.cypherpunks.to/~peter/usenix01.pdf
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