Title: Alternative payment scheme Post by: shesek on January 02, 2014, 03:39:14 PM I had an idea for a payment scheme that uses key derivation, but instead of the payee deriving the addresses, the payer would do it.
It would work like that:
Advantages:
Disadvantages:
What do you think? Title: Re: Alternative payment scheme Post by: oleganza on January 02, 2014, 04:16:57 PM How does it increase privacy compared to payee generating new address for every payment? If you see that payee reuses the address for your payments, what's cheaper for payee: to start generating new addresses or adopting more complex scheme involved receiving some data from the payer (instead of just observing the blockchain)?
Title: Re: Alternative payment scheme Post by: shesek on January 02, 2014, 04:33:42 PM How does it increase privacy compared to payee generating new address for every payment? If you see that payee reuses the address for your payments, what's cheaper for payee: to start generating new addresses or adopting more complex scheme involved receiving some data from the payer (instead of just observing the blockchain)? The main advantage is that the payee doesn't have to be active and provide addresses every time someone wants to make a payment. The payer can independently and without any action from the payee create an address and make the payment. As I wrote above, this makes it easier for cases like an open source project development fund, where people can just send payments without talking with the payee first. Title: Re: Alternative payment scheme Post by: ffe on January 05, 2014, 06:49:34 AM Its a really thin abstraction layer and doesn't require any protocol changes It does require the payee to publish his full public key. That is not common practice today. Bitcoin receive addresses are hashes of public keys and can't be used to derive related keys. Nice idea, though. See this related topic: This added note is to show how Alice allows a server fronting her business to verify that she owns a blinded transaction without requiring the server to have her secret key thus protecting her wallet if the server is hacked. Its done this way: Alice generates a secondary key used to verify blinded transactions from her master key. Her private key is a. She generates a verifier private part b by hashing a, b = Hash(a). Let the public part of a be A and the public part of b be B. A = aQ and B = bQ. The doublet A,B is published as the blind transaction enabling public key. A,B and the private verifier b are given to the server she is using to manage monitoring the block chain for her. With b the server can verify transaction ownership but not spend. Hacking the server does not give you a. A sender would recognize A,B as a blindable key. The sender then generates "X" as follows: s = Hash(m,yB); X = sA. The sender sends coin to X. A server holding verifier "b" can check every new transaction for the property that s = Hash(m,bY) and X = sA to know to add the coins to the balance in Alices wallet. (Note yB = bY). Notice that the server does not need a to verify the transaction. The server can verify X but cannot generate the private part of X. Alice later generates "x", the private part of "X", as follows: She is given m and Y from the transaction; then s = Hash(m,bY); x = sa (modulo a large prime determined by the ECC); She can check that X = xQ. Alice can now sign a prepared transaction using x and publish the signed transaction when spending. Title: Re: Alternative payment scheme Post by: grau on January 05, 2014, 10:24:24 AM The idea is incomplete without a solution for key revoke by the payee, since payee's private key might be compromised.
Once you add that aspect you are likely back to a protocol where payee provides payment address. |