Subject: Re: [Bitcoin-development] Optional "wallet-linkable" address format - Payment Protocol

From: "Jeremy Spilman" <[email-masked]>
Date: Wed, 19 Jun 2013 14:58:06 -0700

Hi Alan,

> “BIP 32 does not prescribe a way to use multiple chains like you described 
> with the convenient type-2 derivation (though we could create a variant 
> that does)”

What do you think is missing from BIP32 for this? A wallet creates a 
child-node using the public / type-2 CDF, hands out the PubKey/ChainCode, 
and then generally expects transactions to come in starting at /0 and 
incrementing monotonically.

Also, I'm not sure I follow your point about the 128kB hardware wallet --  
it's a signing device, so assuming it's even validating output amounts, at 
worst it cares about the number of inputs to the outputs being spent, but in 
many cases you're just handing it a sighash and the BIP32 "path" 
(/1/54/27/0) to generate the right private key for signing. The hardware 
wallet is not actually listening on the P2P network and detecting payments, 
so it's unaffected by dedicating child-nodes to each contact.

Consider the benefits of gaining critical mass of support for a technique 
which [I think] can be used in all cases, and increases security and privacy 
for everyone. I think there are huge benefits to leaving the age of 'single 
address generation' behind us...

Thanks,
--Jeremy