Date: Fri, 16 Dec 2011 09:46:33 +0100
From: Pieter Wuille <pieter.wuille@gmail.com>
To: bitcoin-development@lists.sourceforge.net
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Subject: Re: [Bitcoin-development] Fwd: [BIP 15] Aliases
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On Thu, Dec 15, 2011 at 04:26:38PM +0800, Walter Stanish wrote:
> Interaction is a requirement, since there seems to be a widely felt
> need to preserve anonymity through the use of temporary addresses.
> Generating a temporary address requires some actual processing to
> achieve, since the issuing of the new address cannot be done without
> interacting with the entity hosting the wallet (unless I'm missing
> something?).

Just replying to this one comment: yes, some interaction is always
necessary, but not necessarily directly with the entity hosting the wallet.
There are some EC crypto tricks to do this (often mentioned under
"deterministic wallets" before):

The wallet-hosting entity has a private key x, with public key X.
The address-generating entity knows X, and generates a fresh private
key y for each transaction. For each, it calculates Z=y*X, and asks
the client to pay to hash160(Z). Afterwards, it can send a bunch of
y's to the wallet hosting service, which can reconstruct z=y*x for
each. Alternatively, the y's can be generated according to a predefined
scheme instead.

-- 
Pieter