BIP 32 HD wallets, accounts should be labels not numbers

Can this be amended? I think it makes much more sense to allow people to input labels not numbers at this level.

General category names for different accounts is much more human than numbers, and you can still use incrementing numbers if you prefer.

On Mon, Dec 3, 2012 at 2:49 PM, Amir Taaki <zgenjix@yahoo•com> wrote:

> Can this be amended? I think it makes much more sense to allow people to
> input labels not numbers at this level.
>
> General category names for different accounts is much more human than
> numbers, and you can still use incrementing numbers if you prefer.
>

There is no way to iterate over all strings. The intention is that a wallet application can detect a new account that becomes in use (e.g. during disaster recovery), so the accounts get assigned incrementing numbers.

I wouldn't mind adding the ability to do "non-standard derivations" using arbitrary strings, if this recoverability property is not desired.

ok, also what is the reasoning behind serialising points using a compressed format before going into the hash function? I'm looking at the sec1-v2.pdf and the compression format is a little confusing.

I think the octet string for X is 32 bytes (using q = curve.order) and secp256k1 is a prime field so we follow step 2.2.1

________________________________ From: Pieter Wuille <pieter.wuille@gmail•com> To: Amir Taaki <zgenjix@yahoo•com> Cc: "bitcoin-development@lists•sourceforge•net" <bitcoin-development@lists•sourceforge•net> Sent: Monday, December 3, 2012 2:54 PM Subject: Re: [Bitcoin-development] BIP 32 HD wallets, accounts should be labels not numbers

On Mon, Dec 3, 2012 at 2:49 PM, Amir Taaki <zgenjix@yahoo•com> wrote:

Can this be amended? I think it makes much more sense to allow people to input labels not numbers at this level.

>
>General category names for different accounts is much more human than numbers, and you can still use incrementing numbers if you prefer.
>

There is no way to iterate over all strings. The intention is that a wallet application can detect a new account that becomes in use (e.g. during disaster recovery), so the accounts get assigned incrementing numbers.

I wouldn't mind adding the ability to do "non-standard derivations" using arbitrary strings, if this recoverability property is not desired.

-- Pieter

On Mon, Dec 03, 2012 at 06:48:34AM -0800, Amir Taaki wrote:

> ok, also what is the reasoning behind serialising points using a compressed
> format before going into the hash function? I'm looking at the sec1-v2.pdf
> and the compression format is a little confusing.

I don't think there is a compelling reason to encourage uncompressed public keys anymore on the network. They take more space in the block chain for no additional value whatsoever. Software may of course continue supporting uncompressed keys if they wish to provide compatibility, but for a new standard, I think it makes sense to standardize on just compressed keys. And since that software thus needs to support the compressed encoding, there is no reason to use a different encoding inside the derivation scheme itself.

Regarding the encoding itself, it is not hard: just 0x02 or 0x03 (depending on whether Y is even or odd) followed by the 32-byte encoding of X. Decoding is harder, but is never needed in the derivation. Software internally can use any representation (and it will), which in almost all circumstances stores both X and Y (and even more). Decoding compressed public keys is somewhat harder, as Y must be reconstructed (but the algorithm isn't hard) - this is only necessary when someone wants to import an extended public key though for watch-only wallets.