Skip to content

Zero Knowledge Tests (ZKP), state of the art in cryptography

June 8, 2020

Basically, the operation of a Zero Knowledge Test or ZKP, is to create a common authentication method. One where there is no need to reveal complete secrets to achieve the goal of disclosing sensitive information. Consequently, If no confidential information is revealed, it is impossible to steal the secret, which offers a high level of security.

So í we need the basic functioning of the ZKP, is to generate a system that does not disclose information but allows third parties to verify its existence. So í Our system creates two parts that are essential for the operation of a ZKP, the tester and the examiner.

The tester’s role is to generate the secret and keep full control over it. During the examiner, You can also easily check the authenticity using cryptographic tests. they allow it. Of course, these cryptographic principles are extremely complex and ambiguous. For example, the non-interactive zero knowledge tests (zk-SNARK) or the blind signatures by David Chaum are just a few examples of ZKP, each with its own special features.

The example of the cave of Al í Bab á

Zero Knowledge Tests (ZKP), state of the art in cryptographyZero Knowledge Tests (ZKP), state of the art in cryptography

However, the theoretical and practical difficulties of zero knowledge tests were complex not only for many crypto specialists, but also for the general public. It was like it was released in 1992; How can you explain the Zero Knowledge Protocols to your children? A simple article by Louis Guillou, Jean-Jacques Quisquater and Thomas Berson, in which they performed the Zero Knowledge Tests using a simple example called “The cave of Al í Bab á“”

Basically, this example says the following:

Imagine a cave whose entrance is divided into two parts and forms a ring that ends with a door. This door can only be opened if the corresponding magic words are spoken for this purpose. Once open, the person can go to the other side.

In this example we have Maria and Pablo. Maria knows the magic words and takes Pablo to the cave to provide him with irrefutable evidence that she knows the magic words. So í Well, Maria leaves Pablo at the entrance to the cave as she enters one of the corridors. When she reaches the door, she says the magic words, manages to go to the other side and continue on until she comes from the other hall to the entrance where she is; Paul.

At this point, Pablo can assume that María may also have cheated, prompting you to do the same thing repeatedly. Mar í a does it and every time Mar í a entering on one side of the corridor and exiting on the other clearly shows that she knows the magic words. In this way, María managed to demonstrate to Pablo that she knows the magic words that open the door to the cave, but she never revealed them to her.

As we can see, a simple example shows everyone how the Zero Knowledge Tests (ZKP) work.