Sorry for keeping this short but I'm in holiday and reading/writing on my
phone is a pain.

On Aug 24, 2011 4:12 PM, "Gavin Andresen" <gavinandresen@gmail.com> wrote:
>
> It seems to me the fastest path to very secure, very-hard-to-lose
> bitcoin wallets is multi-signature transactions.
>
> To organize this discussion: first, does everybody agree?
It's a great way for companies to secure their assets.

>
> ByteCoin pointed to a research paper that gives a scheme for splitting
> a private key between two people, neither of which every knows the
> full key, but, together, both can DSA-sign transactions.  That's very
> cool, but it involves high-end cutting-edge crypto like zero-knowledge
> proofs that I know very little about (are implementations available?
> are they patented?  have they been thoroughly vetted/tested?  etc).
> So I'm assuming that is NOT the fastest way to solving the problem.
>
> If anybody has some open-source, patent-free, thoroughly-tested code
> that already does DSA-key-splitting, speak up please.
Since. we have the possibility o add other signature schemes to the protocol
we could add an rsa-like scheme which allows m-out-of-n signatures. It works
by distributing shares of the key which are points on a curve having the
actual key as 0-value. It does not require special length for the key so if
ecdsa allows something similar there need not be anything changed.
>
> I've been trying to get consensus on low-level 'standard' transactions
> for transactions that must be signed by 2 or 3 keys; current draft
> proposal is here:
>  https://gist.github.com/39158239e36f6af69d6f
> and discussion on the forums here:
>  https://bitcointalk.org/index.php?topic=38928.0
> ... and there is a pull request that is relevant here:
>  https://github.com/bitcoin/bitcoin/pull/319
>
>
> I still think it is a good idea to enable a set of new 'standard'
> multisignature transactions, so they get relayed and included into
> blocks.  I don't want to let "the perfect become the enemy of the
> good" -- does anybody disagree?

Would be a first step.
>
> The arguments against are that if the proposed standard transactions
> are accepted, then the next step is to define a new kind of bitcoin
> address that lets coins be deposited into a multisignature-protected
> wallet.
>
> And those new as-yet-undefined bitcoin addresses will have to be 2 or
> 3 times as big as current bitcoin addresses, and will be incompatible
> with old clients.
>
> So, if we are going to have new releases that are incompatible with
> old clients why not do things right in the first place, implement or
> enable opcodes so the new bitcoin addresses can be small, and schedule
> a block chain split for N months from now.
>
> My biggest worry is we'll say "Sure, it'll only take a couple days to
> agree on how to do it right" and six months from now there is still no
> consensus on exactly which digest function should be used, or whether
> or not there should be a new opcode for arbitrary boolean expressions
> involving keypairs.  And people's wallets continue to get lost or
> stolen.
>
>

Just wanted to point you in that alternative direction as it would possibly
keep backward compatibility and allow multisignature.

Regards,
Chris
>
> --
> --
> Gavin Andresen
>
>
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