[Cryptography] Is it mathematically provably impossible to construct a mechanism to test for back doors in programs?

[ianG]

On 6/06/2014 02:38 am, Phillip Hallam-Baker wrote:
> On Thu, Jun 5, 2014 at 2:20 PM, Bear <bear at sonic.net> wrote:
>> On Tue, 2014-06-03 at 13:03 -0400, Phillip Hallam-Baker wrote:
>>
>>> Now obviously there is a theoretical possibility that they all might
>>> collude and default but it is pretty unlikely that they would and it
>>> would certainly be noticed. I think that is far better in practice
>>> than the BitCoin block chain with its known vulnerability to unwinding
>>> transactions.
>>
>> No, it isn't a theoretical possibility.  It *IS* the threat model,
...
> No, it is A threat model. Don't use the definite article when it does not apply.


This is a point worth stressing, although Bitcoin fanboys are going to
be disgusted.  For the Bitcoin design, government is THE threat.  For
everyone else -- including all the users -- it is only one of the threats.

For this reason, Bitcoin has little or no support for user
authentication.  Bugger all in the way of application security (hence
the rash of cold wallet startups).  A joke when it comes to governance
features (e.g., everyone bought into Mt.Gox until it failed and now the
learning begins).  A privacy approach that is a giggle, published
psuedonymous ledger, oh my.

And this is before we get to the exotic systemic threats such as the
Gresham's effect.

Why?  Because THE threat excluded from minds all the other threats that
people might worry about:  theft external and internal, merchant and
exchange fraud, privacy & snooping, etc.

Bitcoin community is full of people who think that THE threat is THE
model.  They're wrong, but learning is only one theft away...


> And not a very good one.


I read somewhere that there have been 30 major Bitcoin thefts involving
values greater than a million bux.  Bitcoin is a community of beginners
losing money to idiots and fraudsters.

So what do we do about it?  The solution I think is to invent a new
generation (c.f. Ethereum, clean piece of paper) that is focused on a
more user-oriented package of security and values.  And in the short
term, use Bitcoin for its working abilities.  But migration is needed in
the medium term, being 3-5 years.



iang