Zk-SNARK and its role in protecting the privacy of blockchains
Zk-SNARK, short for “zero-knowledge succinct non-interactive argument of knowledge,” is a zero-knowledge cryptography proof protocol. The practical implementation of zk-SNARK has come into effect due to the traceable and public nature of the blockchain transactions. This technique gives the user the advantage of having certain information without compromising it with another party. Zcash, a cryptocurrency application, recently used zk-SNARK technology to combat the privacy issues of Bitcoin-type blockchains.
Privacy has always played a prominent role in the transaction of cryptocurrencies (such as Bitcoins). But over the years, the lack of anonymity in the same has been embraced by computer scientists, hackers and law enforcement agencies.
The problem can be avoided by using a special cryptocurrency, called Privacy Coins, which is backed by the zk-SNARK technology. One such example is Zcash (CRYPTO: ZEC), a cryptocurrency that performs encrypted transactions with zk-SNARK as its core technology.
Zk-SNARKs are specifically zero-knowledge proofs, the concept of which dates back to the late 1980s. These zero-knowledge proofs refer to a situation where two users participating in an encrypted transaction can verify to each other that they are in possession of important information (e.g. a secret key) without revealing its contents.
This evidence is concisely, which means that the verification can be done within a time frame of milliseconds, while the size of the proof is a few hundred bytes at most. Unlike the early zero-knowledge proofs that required back-and-forth interactions between the prover and the verifier, zk-SNARKs non-interactive nature requires the prover to send only a single message to the verifier.
In generic terms, validation of a cryptocurrency transaction is performed by the network by ensuring the fulfillment of certain conditions. The reason behind the popularity of zk-SNARK is that these engineered proofs allow the sender to prove these conditions without revealing any addresses or the amount involved in the transaction.
To achieve this, some of the blockchain network’s consensus rules are encoded in zk-SNARK. Additionally, during transactions, zk-SNARK turns what needs to be proven to the verifier into some algebraic equations that can be solved without revealing any sensitive information.
Disadvantages and advantages of zk-SNARK
The most outstanding advantage of zk-SNARK technology is the facilitation of shielded transactions over blockchain-based networks while preserving information about the user’s identity as well as transactions.
Zk-SNARK is becoming increasingly useful in the blockchain networks of various business settings (e.g. food, healthcare and pharmaceuticals) to prevent the leakage of sensitive business information to competitors.
Another important use case of zk-SNARK is to maintain self-overwhelming identity, which means using zero-knowledge proofs to prove claims about one’s identity without releasing any sensitive information to another party.
Along with its advantages, there are some challenging aspects of zk-SNARK that prevent its widespread use. For example, to maintain brevity and efficiency aspects of zk-SNARK, the provers have to spend a lot of money on high-computing computers that can generate the proofs and also store their transcripts.
Privacy coins using the zk-SNARK technique should take steps to ensure that the private key of the specified protocol does not fall into the hands of the wrong personnel who can generate fake evidence and fake funds.
Therefore, although zk-SNARK is a fascinating cryptographic concept that has real potential to provide privacy to users, developers need to work on its various drawbacks to make it more useful in terms of security, scalability, and efficiency.