Author: James MacWhyte 2016-08-09 00:18:21
Published on: 2016-08-09T00:18:21+00:00
A proposal has been made to hide the entire content of bitcoin transactions, including inputs and outputs, and only publish the hash of inputs and outputs in the blockchain. The plaintext of inputs and outputs will be sent directly to the payee via a private message and never go into the blockchain. To protect against double-spends, the payer has to publish another hash, which is the hash of the output being spent. This hash is called a spend proof, and any attempt to spend the same output again will produce exactly the same spend proof. The proposed design requires each private transaction to have exactly one input, i.e. to consume exactly one previous output, so that coin histories do not grow exponentially but linearly, and only the current owner of the coin needs to store the history, not every bitcoin node. The value of this information for potential adversaries arguably decreases with time.However, there are a few limitations to this proposal. After user A sends a private payment to user B, user A will know what the spend proof is going to be when B decides to spend the coin.The Bitcoin Blockchain Confidential Transactions (BBC) is a new privacy preserving currency that operates on top of the Bitcoin blockchain, without requiring a hard or soft fork. The same private keys and addresses can be used for both BBC and the base currency BTC. Every BCC transaction needs to be enclosed by a small BTC transaction that stores the OP_RETURNs and pays for the fees.The use of multiple addresses and storing relatively small amounts on each address can avoid privacy leakage for users sending a lot of private transactions with so many OP_RETURNs as their number will roughly indicate the total amount. However, exchanges and large merchants are likely to accumulate large coin histories, which could be fragmented, outdated, and incomplete. Although there has been no feedback on the concept so far, it was originally posted on BCT.
Updated on: 2023-06-11T19:24:24.700898+00:00