Lelantus protocol รูปแบบใหม่เพื่อความเป็นส่วนตัวมากขึ้นของ Zcoin

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LELANTUS protocol
Anonymous Payment System

https://eprint.iacr.org/2019/373

Lelantus: Towards Confidentiality and Anonymity of Blockchain Transactions from Standard Assumptions

Aram Jivanyan

Abstract: We propose Lelantus, a new anonymous payment system which ensures both transaction confidentiality and anonymity with small proof sizes, short verification times and without requiring a trusted setup.

Inspired by the Zerocoin protocol, Lelantus extends the original Zerocoin functionality to support confidential transactions while also significantly improving on the protocol performance. Lelantus proof sizes are almost 17 times smaller compared to the original Zerocoin proof sizes. Moreover, we show how to support efficient aggregation of the transaction proofs, so that the proof verification, while asymptotically linear, is very efficient in practice.

Lelantus builds on the techniques of Confidential Transactions, Zerocoin and One-out-of-Many proofs and its efficiency is particularly well-suited for enabling private blockchain transactions with minimal trust required while employing well-studied cryptographic assumptions.

Category / Keywords: cryptographic protocols / Zero-knowledge Proofs, Confidential Transactions, Zcoin, One-out-of-Many Proofs, Double-blinded commitments, Bulletproofs, Lelantus, Private Transactions

Date: received 7 Apr 2019, last revised 3 Jun 2019

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อ่านเพิ่มเติม https://eprint.iacr.org/2019/373.pdf

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Lelantus builds on from Sigma, and allows users to burn any amount which they can then redeem any partial amount from, while keeping the rest in a burnt state.

With traditional Zerocoin or Sigma, the most efficient way to privately spend 153 coins would require 100 + 50 + 1 + 1 + 1 coins: meaning that you would need a minimum of 5 Zerocoin spends, occupying 125 kB of space. With each spend taking 300ms to verify, that’s around 1500ms of verification time. This also assumes that you had these Zerocoin mints to begin with: most users require more Zerocoin spends if they don’t have the ideal mint denominations on hand.

With Lelantus, this is greatly improved. To achieve the same private spend of 153 coins, a user simply has to use any of the mints they have done before – any arbitrary amount – and do a spend. The minimum number of spends now required is just one, and verification would take between 20 and 30 ms with batch verification, or 300 – 400 ms for a single proof.

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Lelantus จะช่วยเพิ่มเรื่องของ privacy มากขึ้น และเพิ่มความเร็วในการยืนยัน transaction จาก 200-300s -> 20-30ms
2 เรื่องหลักที่ Lelantus เข้ามาช่วยทำให้ดีขึ้น

Confidentiality : Hiding the transferred amounts, คือสามารถซ่อนจำนวนของ XZC ที่เกิดจากการโอนระหว่าง account id ได้
Anonymity: Hiding the identities of the sender and/or receiver in a transaction : สามารถซ่อนสิ่งที่ยืนยันได้ของผู้รับและผู้ส่ง ระหว่างการทำ transaction การโอนเหรียญ

Protects the private information of customers’
purchasing behavior and trade details
• Safeguards against hackers who might try to
target large wallets
• Enables protection of clients and suppliers
lists for businesses
• Enables protection of financial information
during counterparty relationship
Privacy coins offer a range of critical value-adding features to all types of users.
Prevents financial Data Collection
Enables individuals to reclaim their financial
sovereignty fully
Enables full financial privacy for enterprises hiding
business performance related information
No trade-off are applied between confirmation of
validity of transactions and its privacy.