[martindale]

Multiple SINs (read: identities) are an intended benefit of this mechanism. In fact, nonces are verified per SIN, so this provides sequence enforcement per client as we intend for each device to have its own SIN.

We have a reference implementation for key management in [our example client](https://github.com/bitpay/node-bitpay-client)[1], and will be publishing a more formal document as soon as it is complete.

[1]: I am fully aware that HN does not support proper Markdown.

[siralonso]

Not only does HN not support markdown, but it breaks links you write using markdown :)

Really nice work. Question - if you generate the private keys client-side and use a password only to decrypt them for use (still client-side), wouldn't this make associating accounts across devices kinda difficult? As insecure as email/password auth is, it's pretty portable.

Looking forward to playing with bitauth!

[martindale]

Not particularly. The pattern for resolving this is already increasingly commonplace; login with your username and password, then confirm the login from one of your already authorized devices.

In fact, this even lends itself to expansion into n-factor authorization methods.