The Confidential Transactions technology received a new development impulse.
The technology, which was first announced in 2015 by Dr. Adam Beck, uses the so-called "Pederson's obligations" and assumes that it is possible to make the transferable amount visible only to the direct participants of the transaction or the third party assigned to them.
However, such transactions are not in themselves a universal solution, since they hide only the amount of the transfer, and not the address of the sender and the recipient.
A new approach to the issue was suggested by Bitcoin Core developer Gregory Maxwell. His model involves using the CoinJoin method to combine transaction outputs into one large transaction, which will hide the links between users from outside observers.
As Maxwell says, in this case the amount of payment will be available only to the "sender, recipient and those to whom they will provide special keys for viewing information."
In addition to increased privacy, the proposed method solves another important task related to the issue of scaling. In particular, it allows you to significantly optimize the weight of transaction confirmation.
It is necessary to understand that the technology of Confidential Transactions, in the background of all its advantages, is rather resource-intensive. It is this problem that Maxwell decided, optimizing a number of indicators.
The primary advantage of this approach is that it can be constructed without any substantial new cryptographic assumptions (e.g., only discrete log security in our existing curve), that it can be high performance compared to alternatives, that it has no trusted setup, and that it doesn't involve the creation of any forever-growing unprunable accumulators. All major alternative schemes fail multiple of these criteria (e.g., arguably Zcash's scheme fails every one of them).
Developer, Bitcoin Core
Charlie Lee, creator of Litecoin, found this technology very interesting.
I'm excited to see progress on Confidential Transactions. Fungibility is the only feature of good money that Bitcoin/Litecoin is missing.
I look forward to adding this to Litecoin when it is ready. And this can be done with a soft fork. Stay tuned!
— Charlie Lee [LTC] (@SatoshiLite) 14 ноября 2017 г.
According to Maxwell, the size of a typical bitcoin transaction using the advanced technology of Confidential Transactions can be reduced by about 20 times.