Anonymity coins are different from encrypted digital currencies such as Bitcoin. They are sought after because of their anonymity, but they are also controversial because of their anonymity.
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Balancing User Privacy and Accountability
For balancing user privacy and accountability, let's first talk about whether it is necessary.
First of all, from the perspective of the demand scenario of anonymous coins, anonymous coins represented by Monero, Dash, and Zcash are inseparable from illegal transactions such as money laundering. It can be said that these illegal transactions have also boosted the growth of these anonymous coins (but who can Say that the rise of Bitcoin has nothing to do with the dark web). For a long time, the public has also formed a subconscious mind, that is, mentioning anonymous coins will associate words such as money laundering and dark net.
But is there a large demand for anonymous coins only in illegal scenarios?Odaily has reported on privacy coins, believes that the high anonymity of anonymous coins is not the same as "the first choice for money laundering". In the field of conventional payments, there are also demand scenarios for anonymous coins, such as business occasions that require high privacy; or in daily life, people avoid talking about how much money they have in the bank, so the hidden fund balance There is demand for anonymous coins for transactions and exchanges.
recent,recent,June 20, 2018, the deputy director general of the US Secret Service (US Secret Service) said at a congressional hearing: "We must continue to promote related controls on digital currencies on an international scale through the Financial Action Task Force and other forms. We should also consider taking more measures. legislative or regulatory action to address the challenges associated with anonymous cryptocurrencies.”
Duncan Wong believes that anonymous coins are the future, but anonymous coins like Monero and Dash that only have privacy and no supervision have drawbacks.Some criminal groups will use anonymous coins to conduct criminal transactions such as drug trafficking and human trafficking, so some countries (such as Japan) will even block Monero and Dash from their own exchanges. Duncan Wong said that unlike other anonymous coins,The main purpose of ABE is to achieve accountability and auditable privacy.
ABE is divided into general privacy, accountability privacy, and complete privacy in terms of privacy levels. Among them, accountability privacy is used to balance user privacy and accountability.
Regarding accountability and privacy, simply speaking, from the perspective of users, ABE is the same as some other anonymous coins. The address of the sender, the address of the receiver, and the transaction amount are all invisible, but for regulators/enterprises, Transactions can be tracked, and regulators/enterprises can know the wallet addresses and transaction amounts of both parties to the transaction.
From a technical point of view, Duncan Wong said that ABE is derived based on Monero’s CryptoNote (an application layer protocol), and the method is basically the same (Monero did not have a security model before, and ABE made a model to prove its security).
In terms of hiding the address of the sender and receiver, ABE consists of CryptoNote The two main features of -ring signatures (ring signatures, which hide the identity of the sender through a hybrid method) and unlinkable payments (unlinkable transactions, generate a one-time public key for each transaction, and then generate a one-time Stealth address) to realize the hidden address; in terms of hiding the transaction amount, ABE uses Monero’s RingCT (Ring Confidential Transactions) technology to achieve.
It is worth noting that in order to achieve accountable privacy, ABE also introduces a new cryptographic method——verifiable encryption(VE, Verifiable Encryption) technology.
Duncan Wong gave an example, A sent a transaction worth 10 ABE tokens to B, how to make it known to the regulator but not to the public? A can encrypt the transaction value with the public key released by the regulatory agency, and then the regulatory agency decrypts it with a private key (the public does not have a private key) to view the transaction value, so as to achieve both privacy and supervision.
However, Duncan Wong said that the regulatory agency can only see a value after decryption, and cannot verify whether the encrypted value is the value before encryption, that is, A may cheat, and only 5 ABEs are sent to B, but they use 10 ABE for encryption.
So how to avoid cheating? This can be achieved through verifiable cryptography. Duncan Wong said that compared with zero-knowledge proof, the advantage of verifiable encryption technology is that it can improve the overall efficiency.
Verifiable encryption technology has a history of at least 15 years. It was often used in "group signature" before. "Group signature" is somewhat similar to "ring signature" used in cryptocurrencies. The biggest difference is that "group signature" has a central , the center knows who the real signer is, but the public does not.
ABE introduces verifiable encryption technology into ABE's accountable privacy, and this "central" role is played by regulators/enterprises in the ABE network.
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Anti-quantum attack-lattice cipher
How does ABE achieve anti-quantum attack in terms of privacy?
Aiming at the necessity of achieving quantum resistance, Duncan Wong said that most cryptocurrencies currently use the elliptic curve cryptography technology invented in the 1980s as the basis of their signature system, but after the emergence of quantum computing, the NSA publicly reminded this technology in August 2015 that there are security risks. Duncan Wong believes that quantum computers may crack elliptic curve cryptography within 5-10 years.
At present, the mainstream post-quantum cryptography technology hasFour categories：Hash-based cryptography (post-quantum cryptography based on Hash function); Multivariate-quadratic-equations cryptography (post-quantum cryptography based on multivariate quadratic equations); Code-based cryptography (post-quantum cryptography based on coding theory); Lattice-based Cryptography (post-quantum cryptography based on lattice theory).
ABE will among themLattice-based cryptographyTechnology is introduced into encrypted digital currency, based on the mathematical problem of lattice cipher, there is currently no effective algorithm to crack it.
Compared with elliptic curve encryption algorithm (ECC) technology, lattice cryptography technology has the advantage of matrix algorithm and higher efficiency. The disadvantage is that the size of lattice-based public keys, signatures, certificates, etc. is too large, resulting in low efficiency. . Therefore, after the advantages and disadvantages of the lattice cipher are balanced, its efficiency is almost the same as that of ECC, but it can resist quantum attacks.
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Two layers: ABE blockchain layer and IPFS layer
Regarding the future development of the project, Duncan Wong said that in addition to being applicable to the previously mentioned landing scenarios such as real estate, ABE will also develop in the direction of asset-backed securities, such as real estate, stocks and other securities. Assets are tokenized.
In terms of project progress, ABE started research and development last year. It is expected to launch the first testnet before the end of this year and the main chain in the middle of next year.
In terms of team members, the ABE team has about 30 people, most of whom have more than 20 years of experience in cryptography research. Among them, CTO and co-founder Andrew Hon, once served as the head of the Blockchain Core Competence group of the Hong Kong Applied Science and Technology Research Institute. ABE also cooperates with Nanyang Technological University on lattice cryptography technology, and cooperates with Shanghai Jiaotong University and the University of Wollongong (University of Wollongong, Australia) on core cryptography components.
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Related References and Extended Information
Why was Gu Tianle able to "launder money" with Monero, but was caught using Bitcoin?
Practical Verifiable Encryption and Decryption of Discrete Logarithms
Cat and mouse game: How does encryption work against quantum computers?English version:A Tricky Path to Quantum-Safe Encryption
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