[Bitcoin-development] Message Signing based authentication

[slush]

Glad to see that there are more and more people wanting to replace
passwords with digital signatures.

Although such method has been already used on other websites like Eligius
or bitcoin-otc, I dont think theres any standard way to doing so yet.

Two comments to your proposal:

A) message-to-be-signed need to be carefully composed to be both structured
and human readable. It should contain at least:
Desired username/identity handler
Server identifier (url)
Timestamp to prevent replay attack
Server challenge

Then the user can see what he's signing, instead of signing some binary
blob which can contain some evil data.

B)
Same structured data should be a part of html page in some header tag,
ideally signed by server certificate to confirm that the request is valid.
Then the login request can be processed by machine automatically, without a
need of copy&paste by a user.

Slush


On Sat, Nov 2, 2013 at 6:01 AM, <bitcoingrant at gmx.com> wrote:

> Passwords are inefficient by design: frequently we hear news from Sony,
> Square Enix, Adobe, and various others about passwords being compromised,
> databases being copied and stolen. This story remains true in the Bitcoin
> space. In light of the recent Bitcointalk forum breach echoes an increasing
> need for passwords to become a thing of the past.
>
>
>
> In celebration of the 5 year anniversary of the Bitcoin whitepaper, we are
> delighted to introduce the Message Signing based authentication method.
>
>
>
> In brief, the authentication work as follows:
>
>
>
> Server provides a token for the client to sign.
>
> client passes the signed message and the bitcoin address back to the
> server.
>
> server validates the message and honors the alias (optional) and bitcoin
> address as identification.
>
>
>
> http://forums.bitcoingrant.org/
>
>
>
> Above is a proof of concept forum that utilize this authentication method.
> Following Kerckhoffs's principle, this forum only stores the signed message
> and bitcoin address the users provide the first time they use the site,
> both are public information. In addition, there is no database, everything
> is simply an RSS feed. For the sake of usability we have included a redis
> for the sessions, at the cost of additional exposure to potential risks:
> users no longer need to sign a token every time they wish to post.
>
>
>
> All source code will be available on github in the next few days.
>
>
>
> We welcome any feedback or suggestions.
>
>
>
>
>
> ------------------------------------------------------------------------------
> Android is increasing in popularity, but the open development platform that
> developers love is also attractive to malware creators. Download this white
> paper to learn more about secure code signing practices that can help keep
> Android apps secure.
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> _______________________________________________
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> Bitcoin-development at lists.sourceforge.net
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>
>
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