The aim of zk technologies is to minimize some scalability problems experienced in blockchain networks. zk is an abbreviation used for Zero-Knowledge. zk technologies are verification technologies used in blockchain applications.
In zk-SNARK, the party trying to convince the other party of the accuracy of the situation is called the prover, and the party who approves or disapproves is called the verifier.
zk-SNARK represents the concept of succinct non-interactive argument of knowledge. zk-SNARK is an abbreviation of Succinct Non-Interactive Argument of Knowledge. The letter-by-letter expression is as follows:
- zk (Zero-Knowledge)
- S (Succinct)
- N (Non-Interactive)
- AR (ARgument)
- K (of Knowledge)
What Is zk? What Does It Stand For?
It refers to the ability to demonstrate having a piece of information without revealing the information itself to the verifier. This allows the verification can be done without the need for all information to be confirmed.
What Is Succinct? What Does It Stand For?
Succinct refers to the situation of being "short and concise". It represents proving the accuracy of a certain part of data rather than the whole data.
What Is Non-Interactive? What Does It Stand For?
It means that there is no need for the people verifying the proofs presented during zero-knowledge proof to constantly ask questions. It is non-interactive, naturally. For example, when the prover enters the correct data into the desired 5 boxes, the verifier is convinced that the prover has the necessary information without needing to ask any questions, and there is no interaction between them.
What Is Argument? What Does It Stand For?
Argument refers to the evidence used during verification.
What Is Knowledge? What Does It Stand For?
Knowledge refers to the knowledge of the prover in the technology.
When and Where Was zk-SNARK First Used?
Alessandro Chiesa, who first used the term zk-SNARK, is a professor at the University of California, Berkeley. Chiesa and his team used the zk-SNARK term for the first time in the article they wrote for the zk-Proof (zero-knowledge proof) they developed.
The security of SNARKs is dependent on elliptic curves. These elliptic curves used in cryptography are generally based on a randomly selected point and operate on the assumption that it is impossible to detect a discrete logarithm.
What Projects Use zk-SNARK?
Some popular blockchain projects known to use zk-SNARK are:
- Mina
- Aztec
- zCash
- Aleo
Mina
The Mina protocol is a minimal blockchain network that can make decentralized applications more efficient.
Aztec
Aztec is a private blockchain network focusing on using zk technologies.
zCash
zCash is an altcoin that protects its privacy with zk technologies.
Aleo
Aleo is a blockchain network using zk technologies. It can be used faster and more securely than traditional blockchain networks.
What Is the Difference Between zk-SNARK and zk-STARK?
While zk-SNARKs have non-interactive zero-knowledge proof, zk-Starks have scalable and transparent zero-knowledge proof. Therefore, the two technologies provide solutions to different problems and are used accordingly. The use of zk technologies reduces the occurrence of scalability problems in blockchain networks.
How to Describe zk-SNARK Simply?
Imagine two fictional characters. Let's call the person who is the prover A, and the person who is the verifier B.
B has a red and a green ball in each of his hands, but he is colorblind. A is not colorblind but needs to prove it to B. B takes the balls behind his back and switches their positions. Then he shows them to A again. A, not being colorblind, notices that the positions of the red and green balls have been switched.
B asks: Did the positions of the balls change?
A answers: Yes, they did.
Thus, A proves to B that he is not colorblind, even though B couldn't see the colors of the balls. In other words, the prover achieved verification by showing only a part of the necessary information to the verifier.
