"If Bitcoin does have a serious competitor, it will be Monero"

10 dic 2017

John Mcafee "If Bitcoin does have a serious competitor, it will be Monero"
reddit.com/r/Monero/comments/7hi729/john_mcafee_on_info_wars_if_bitcoin_does_have_a/

10 dic 2017

Nota

Here is a quick update on Bulletproofs and their role in Monero. Bottom line: they're awesome, they work, the fees are lower, and they're moving into testnet.

Monero's confidential transactions hide the amounts involved. To ensure that inputs and outputs balance properly in a way that can be verified by anyone, we use commitments that have useful algebraic properties. However, this isn't enough. We also need to ensure that each amount is a positive value that won't risk an overflow, and this is where range proofs come in. A range proof allows anyone to verify that a commitment represents an amount within a specified range, without revealing anything else about its value. Our current range proofs scale linearly in size with the number of outputs and the number of bits in the range (currently 64 bits), meaning they make up the bulk of a transaction's size. Further, this means that a transaction with multiple outputs needs multiple separate range proofs. Not great.

Thanks to a fantastic new paper by Bünz, Bootle, and others (freely available here), there is a more efficient way to handle range proofs. The size of a bulletproof increases only logarithmically with both the size of the range and the number of outputs. This gives us two related types of bulletproofs: single-output and multiple-output. A transaction with multiple outputs can either include several single-output proofs or one multiple-output proof (which is smaller than the separate proofs).

Let's look at the typical two-output transaction, where I send you some XMR and direct the change back to myself. With our current range proofs, the transaction is around 13.2 kB in size. If I used single-output bulletproofs, the transaction reduces in size to only around 2.5 kB! This is, approximately, an 80% reduction in transaction size, which then translates to an 80% reduction in fees as well. The space savings are even better with multiple-output proofs. This represents a significant decrease in transaction sizes. Further, our initial testing shows that the time to verify a bulletproof is lower than for the existing range proofs, meaning speedier blockchain validation.