Syncing files / Alternative backup whist keeping best practises of isolation.

[Alistair Hutten]

Good evening, Alistair here from Australia,

I'm after some help / recommendation to follow best practices (isolation between my different domains)

My Current practice;

• have encrypted vaults (cryptomator) one for personal, and one for work/business,
  
• underlying encrypted files stored within Dropbox

I do it this was because data is encrypted at rest, and more importantly before dropbox sees them, can sync between different devices, when computer dies within an hour have all my documents on new computer again.
although it feels like it, I'm aware there isn't any isolation between those vaults when they are both open, which i know Qubes will fix that.


My Aim;

Certain domains i.e. personal, & work, to have documents sync'd offsite as I'm currently doing, still keeping isolation between them all and having all data encrypted at transmission & rest.

Concern / Questions;
ways i can think of, however open to recommendations / suggestions)

1. Cryptomator & Dropbox within each domain.
• that seems wasteful having all files sync within each domain.
• doesn't that also brake the isolation?
  
2. Dropbox domain which someone shares files across then local domain just runs the Cryptomator?
• is that even do-able?
• am i braking isolation by sharing files?
  
3. sync'd files domain, which has both Dropbox & Cryptomator which the vault is shared personal to personal-vm, and business to business-vm, etc.
• again is that even doable
• and again is that braking isolation as well?
  

really looking forward to anyone's help on the mater.

regards and thank you in advanced.


p.s.
I'm new / green as, stating to migrate away from windows 10, (i know terrible)
just awaiting a USB WiFi i've ordered which I believe will make my laptop compatible so i can jump ship.

[Andrew David Wong]

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On 2016-06-19 04:38, Alistair Hutten wrote:
> Good evening, Alistair here from Australia,
>
> I'm after some help / recommendation to follow best practices
> (isolation between my different domains)
>
> My Current practice;
>

> - have encrypted vaults (cryptomator <https://cryptomator.org/>)
> one for personal, and one for work/business, - underlying encrypted

> files stored within Dropbox
>
> I do it this was because data is encrypted at rest, and more
> importantly before dropbox sees them,

Careful:

* Certain kinds of encryption are easier to break if the attacker has
repeated access to a changing ciphertext.

* If you're not using authenticated encryption, then you're trusting
Dropbox to maintain ciphertext integrity.

> can sync between different devices, when computer dies within an
> hour have all my documents on new computer again. although it feels
> like it, I'm aware there isn't any isolation between those vaults
> when they are both open, which i know Qubes will fix that.
>
>
> My Aim;
>
> Certain domains i.e. personal, & work, to have documents sync'd
> offsite as I'm currently doing, still keeping isolation between
> them all and having all data encrypted at transmission & rest.
>
> Concern / Questions; ways i can think of, however open to
> recommendations / suggestions)
>

> 1. Cryptomator & Dropbox within each domain. - that seems wasteful

> having all files sync within each domain.

Yes.

> - doesn't that also brake the isolation?

Yes (arguably at least partially, depending on whether you, e.g., open
the same files in both domains).

> 2. Dropbox domain which someone shares files across then local
> domain just runs the Cryptomator? - is that even do-able?

Yes, but it might be a hassle, (or you might have to write your own
qrexec tools to make it not-a-hassle).

> - am i braking isolation by sharing files?

Depends on your habits and workflow. Opening the same files in
multiple domains can break isolation in this way.

> 3. sync'd files domain, which has both Dropbox & Cryptomator which

> the vault is shared personal to personal-vm, and business to

> business-vm, etc. - again is that even doable - and again is that
> braking isolation as well?
>

Sorry, I don't understand this scenario. Please try explaining it more
clearly.

>
> really looking forward to anyone's help on the mater.
>
> regards and thank you in advanced.
>
>
> p.s. I'm new / green as, stating to migrate away from windows 10,
> (i know terrible) just awaiting a USB WiFi i've ordered which I
> believe will make my laptop compatible so i can jump ship.
>
>

- --
Andrew David Wong (Axon)
Community Manager, Qubes OS
https://www.qubes-os.org
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[Franz]

On Sun, Jun 19, 2016 at 11:40 AM, Andrew David Wong <a...@qubes-os.org> wrote:

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On 2016-06-19 04:38, Alistair Hutten wrote:
> Good evening, Alistair here from Australia,
>
> I'm after some help / recommendation to follow best practices
> (isolation between my different domains)
>
> My Current practice;
>
> - have encrypted vaults (cryptomator <https://cryptomator.org/>)
> one for personal, and one for work/business, - underlying encrypted
> files stored within Dropbox
>
> I do it this was because data is encrypted at rest, and more
> importantly before dropbox sees them,

Careful:

* Certain kinds of encryption are easier to break if the attacker has
repeated access to a changing ciphertext.

Also, who knows what the future bring and when. Quantic computing promises to be able to crack current encryption systems. When this happens and if you are aware of it, you would need to change all your passwords.

I would not send my encrypted vault over the internet and would not open it with anything different from my vaultVM.

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[Andrew David Wong]

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On 2016-06-19 08:40, Franz wrote:
> On Sun, Jun 19, 2016 at 11:40 AM, Andrew David Wong
> <a...@qubes-os.org> wrote:
>
> On 2016-06-19 04:38, Alistair Hutten wrote:
>>>> Good evening, Alistair here from Australia,
>>>>
>>>> I'm after some help / recommendation to follow best
>>>> practices (isolation between my different domains)
>>>>
>>>> My Current practice;
>>>>
>>>> - have encrypted vaults (cryptomator
>>>> <https://cryptomator.org/>) one for personal, and one for
>>>> work/business, - underlying encrypted files stored within
>>>> Dropbox
>>>>
>>>> I do it this was because data is encrypted at rest, and more
>>>> importantly before dropbox sees them,
>
> Careful:
>
> * Certain kinds of encryption are easier to break if the attacker
> has repeated access to a changing ciphertext.
>
>
>> Also, who knows what the future bring and when. Quantic computing
>> promises to be able to crack current encryption systems. When
>> this happens and if you are aware of it, you would need to change
>> all your passwords.
>

That mainly applies to asymmetric, not symmetric, encryption:

http://pqcrypto.org/

>> I would not send my encrypted vault over the internet and would
>> not open it with anything different from my vaultVM.
>

Data confidentiality is encryption's raison d'être. If you can't send
the ciphertext over the internet, then what's the point of encrypting
it?

- --
Andrew David Wong (Axon)
Community Manager, Qubes OS
https://www.qubes-os.org

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[Franz]

Thanks Andrew, I had a look only at the first paper of you link and it tells that the quantum computer problem is limited to public key encryption. While there is no problem for secret key encryption which would be the case for vault encryption.
 

>> I would not send my encrypted vault over the internet and would
>> not open it with anything different from my vaultVM.
>

Data confidentiality is encryption's raison d'être. If you can't send
the ciphertext over the internet, then what's the point of encrypting
it?

Well my idea was that there is no 100% security guarantee and it is only a matter of relative security. So I considered that keeping my backups in a NAS over a personal LAN was safer that sending them over the internet.

But you link explains that I am wrong and that for any reasonable future secret key encryption is 100% safe.  So thanks Andrew. This confidence certainly gives more peace of mind. 

Best

Fran

[Andrew David Wong]

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Well, it's not that quantum computing presents no problem *at all* for
secret key/symmetric encryption. Symmetric ciphers are still thought
to be vulnerable to Grover's algorithm, which basically means that key
length would effectively be halved (e.g., the strength of AES-256
would be effectively halved to that of AES-128), but this is obviously
much less of a problem than the crypto being completely broken (as
would be the case for RSA, for example).

>
>>>>> I would not send my encrypted vault over the internet and
>>>>> would not open it with anything different from my vaultVM.
>>>>
>
> Data confidentiality is encryption's raison d'être. If you can't
> send the ciphertext over the internet, then what's the point of
> encrypting it?
>
>
>> Well my idea was that there is no 100% security guarantee and it
>> is only a matter of relative security. So I considered that
>> keeping my backups in a NAS over a personal LAN was safer that
>> sending them over the internet.
>

That's fair. I think that might qualify as security through obscurity
(or maybe "security through non-availibility"), but that's not to say
it doesn't still provide some real degree of security.

>> But you link explains that I am wrong and that for any reasonable
>> future secret key encryption is 100% safe. So thanks Andrew.
>> This confidence certainly gives more peace of mind.

Well... I didn't mean to give that impression. IANAC (I am not a
cryptographer), but when it comes to encryption, I don't think we
should say that anything is "100% safe." It's not that the algorithms
are apodictically unbreakable. Rather, we derive our confidence in
them from the fact that lots of smart people have spent lots of time
trying to break them, and no one has been successful yet (that we know
of!). That's why there are competitions to select algorithms.

Also, even if the algorithm is secure, any given implementation you
use might not be. So, even though it's true (as people often say) that
the crypto itself is usually not the weak point in a digital system, I
also don't think (and didn't mean to give you the impression) that
it's "100% safe."

- --
Andrew David Wong (Axon)
Community Manager, Qubes OS
https://www.qubes-os.org
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[Franz]

You are right of course, but I was referring to sending encrypted vault over internet. It is not compulsory to do that. You can certainly live comfortably without doing that. So why should one do that? Only because there is expectation of a reasonable total safety, so that the difference to 100% may be negligible.

But returning to Alistar post, describing the plan to "more importantly before dropbox sees them, can sync between different devices,"

Here, IMHO the difference to 100% in not at all negligible, because if you sync your encrypted vault among different device, it is probably because you want to open it in different devices and this is dangerous. Which is the point of maintaining Qubes if you expose your vault to the much lower security of other systems connected to internet?

Best

Fran

[Andrew David Wong]

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I see what you mean.

I think it still depends on your backup situation, though. If your
only means of having offsite backups is to send (encrypted) backups
over the internet (i.e., you can't physically move disks to another
location or have someone else do it for you), then it may not be
entirely true that you can "live comfortably without doing that." (I
would live uncomfortably knowing that a fire could burn down my house
and my backups along with it, since in that scenario I wouldn't have
any offsite backups.)

In other words, data availability counts for something, and I'm
willing balance confidentiality against availability. (In a sense,
this is obviously true. If I cared only about confidentiality and not
at all about availability, I would just destroy all copies of my data
immediately.)

- --
Andrew David Wong (Axon)
Community Manager, Qubes OS
https://www.qubes-os.org
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[Franz]

Yes you are right, it depends on the user case, imagine someone traveling a lot. There is no easy way to physically store backups.