It is the process of proving that we know a secret without revealing any information about the secret itself.
For an example:
Lets take a deck of cards and following would be the structure of the deck
| Count | Color | Symbol |
|---|---|---|
| 13 | Black | Spade |
| 13 | Black | Clover |
| 13 | Red | Diamond |
| 13 | Red | Heart |
I’ll take a card from this deck. Now I’ll have to prove you that the card I hold on to is red without showing you the card.
showing the card could reveal more information about it ( the number and the symbol )
To prove my claim, I can give all the 26 black cards to you so that you can confirm I don’t have any black cards with me. This will not only prove my claim but it will not reveal any information about the card.