[Cryptography] storage encryption

John Denker jsd at av8n.com
Sat Jul 21 19:51:30 EDT 2018

On 07/19/2018 11:54 AM, John Kelsey wrote:

> What kind of access to the documents is needed?

Their goals are the same as everybody else's:
  confidentiality + integrity + availability

If you want an example, here's an obvious use-case:
  Each of N people are told to write their chapter of
  a report, then put a draft on the cloud drive where
  all N can see it.  There is no need for the other
  M-N members of the organization to read the draft,
  or even know that it exists.

An easy-to-read overview of small-organization security
issues, including some useful checklists, is here:

> What are the threats they are worried about? 

There are too many threats to mention, even if I knew
what they all are, which I don't.

If you want an example, start with a Podesta-style
spearphishing attack.  That worked in 2016.  Attackers
are going to keep using it until it stops working.

Reportedly, the Hillary campaign was advised to use
2fa (which might have blunted the spearfishing attack),
but decided that would be too burdensome.

On 07/17/2018 04:02 PM, Tom Mitchell wrote:

>> A file has a single key.   

True but not the whole story, I would hope.  Methods
for dealing with multi-recipient messages have been
around for eons.  See e.g. PGP.  Single session key
versus multiple access keys.

>> Are all files encrypted with the same key?

I would hope not.  Neither same session key nor
same access keys.

>> Do all members of the group have equal access and trust.

I would hope not.  Need-to-know reduces the attack
surface by a factor of N/M, ideally.

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