Feige–Fiat–Shamir identification scheme
Okay, let’s imagine that you are trying to enter a secret clubhouse with a secret password. But, the bouncer at the door doesn't trust you and wants to make sure that you are really you before letting you in. What can we do?
Well, the feige-fiat-shamir identification scheme is like a magic trick to ensure that you are who you say you are, without having to reveal your secret password or identity to anyone else.
Here’s how it works: Instead of telling the bouncer your password or showing your ID, you and the bouncer agree on a secret number, let's call it "x". You keep this number very secret, and the bouncer doesn't know it.
Then, the bouncer gives you a bunch of challenges or questions, like "What's the next number in this sequence: 1, 2, 3, _____?" or "What's 5 plus 7?"
Instead of answering these questions directly, you use your secret number “x” to come up with a new number, let’s call it "y". You do some secret calculations with “x” and the question asked, and nobody else can figure out what this new number is.
You then tell the bouncer the answer, which is your new secret number "y". The bouncer has no idea how you got the answer and whether or not you actually know the secret password. But here’s the cool part: the bouncer can double-check if you are correct without actually knowing your secret number "x"!
This is possible because the feige-fiat-shamir scheme uses something called "public-key cryptography". It’s like having two different keys, one to lock a door and one to unlock it. The bouncer has a “public key” that can be used to verify your answer is correct, but it can't be used to figure out any other information, like your secret password or identity.
So, you get to enter your secret clubhouse and nobody else knows your secret password or identity. It's like magic!
Of course, this is a very simplified explanation of how the feige-fiat-shamir scheme works, but even a 5-year-old can understand the basic idea of keeping secrets and verifying answers without revealing everything.
Well, the feige-fiat-shamir identification scheme is like a magic trick to ensure that you are who you say you are, without having to reveal your secret password or identity to anyone else.
Here’s how it works: Instead of telling the bouncer your password or showing your ID, you and the bouncer agree on a secret number, let's call it "x". You keep this number very secret, and the bouncer doesn't know it.
Then, the bouncer gives you a bunch of challenges or questions, like "What's the next number in this sequence: 1, 2, 3, _____?" or "What's 5 plus 7?"
Instead of answering these questions directly, you use your secret number “x” to come up with a new number, let’s call it "y". You do some secret calculations with “x” and the question asked, and nobody else can figure out what this new number is.
You then tell the bouncer the answer, which is your new secret number "y". The bouncer has no idea how you got the answer and whether or not you actually know the secret password. But here’s the cool part: the bouncer can double-check if you are correct without actually knowing your secret number "x"!
This is possible because the feige-fiat-shamir scheme uses something called "public-key cryptography". It’s like having two different keys, one to lock a door and one to unlock it. The bouncer has a “public key” that can be used to verify your answer is correct, but it can't be used to figure out any other information, like your secret password or identity.
So, you get to enter your secret clubhouse and nobody else knows your secret password or identity. It's like magic!
Of course, this is a very simplified explanation of how the feige-fiat-shamir scheme works, but even a 5-year-old can understand the basic idea of keeping secrets and verifying answers without revealing everything.