Asymmetric Encryption with RSA

Have you ever wondered how your web browser securely exchanges a secret password with your bank's server, even when anyone on the Wi-Fi network could be snooping? The answer is Asymmetric Encryption via RSA!

How RSA Encryption Works

1. Key Generation: Bob generates a Public Key and a Private Key.
2. Sharing: Bob shares his Public Key with Alice. (It doesn't matter if a hacker intercepts this).
3. Encryption: Alice writes a secret message and uses Bob's Public Key to encrypt it into a jumbled mess (ciphertext).
4. Transmission: Alice sends the ciphertext to Bob. Even if the hacker intercepts it, they can't read it, because the Public Key cannot decrypt the message!
5. Decryption: Bob uses his Private Key to decrypt the ciphertext back into the original message.

Why Not Use RSA for Everything?

Because RSA relies on complex math (factoring the product of two large primes), it is computationally very slow compared to symmetric encryption (like AES). Furthermore, RSA can only encrypt small amounts of data (smaller than the key size itself).

In practice, RSA is usually used to securely exchange a fast AES key, and then AES is used to encrypt the actual data (this is exactly how TLS/HTTPS works).

Try acting as both Alice and Bob using our RSA encryption and decryption tool!