One-Way Functions

➡️

One-Way Functions

The foundation of computational cryptography

🎯 Challenge

💡 Story

🎮 Sandbox

📚 Deep Dive

✅ Quiz

▶️ Simulate

🐛 Debug

Easy to Lock, Impossible to Pick

I can compute something in milliseconds that you cannot reverse in a billion years...

This asymmetry between forward computation and reverse computation is the foundation of all public-key cryptography.

The Impossible Reversal Challenge

I computed 5^x mod 23 = 17 in microseconds. Can you find my secret value of x?

The Forward Direction (Easy)

5

base (g)

^

?

secret (x)

mod

23

modulus (p)

=

17

result

With small numbers, you could try all values of x (1, 2, 3...) until you find the answer.
But imagine if the modulus was a 2048-bit number with 617 digits!

Try to find x:

With only 22 possibilities (1-22), brute force works. With 2^2048 possibilities, it does not.

Why can't I just reverse the computation?

Select an answer to continue!

The Secret

The Secret

The Secret

The Secret

One-Way Functions

The foundation of computational cryptography

Easy to Lock, Impossible to Pick

I can compute something in milliseconds that you cannot reverse in a billion years...

The Impossible Reversal Challenge

The Forward Direction (Easy)

5

^

?

mod

23

=

17

Try to find x:

Why can't I just reverse the computation?

One-Way Functions

The foundation of computational cryptography

Easy to Lock, Impossible to Pick

I can compute something in milliseconds that you cannot reverse in a billion years...

The Impossible Reversal Challenge

The Forward Direction (Easy)

5

^

?

mod

23

=

17

Try to find x:

Why can't I just reverse the computation?