Authentication In Public-Key Systems:

Authentication in public-key systems is the process of verifying the identity of a sender or entity using cryptographic keys. Here’s how it works:

1. Key Pair Generation: Each user generates a pair of cryptographic keys: a public key and a private key. The public key is freely shared, while the private key is kept secret.
2. Signature Creation: When a sender wants to authenticate themselves or prove their identity, they use their private key to create a digital signature for the message or data they’re sending.
3. Verification: The recipient of the message or data uses the sender’s public key to verify the digital signature. If the signature can be decrypted using the public key and matches the original message, it confirms that the sender possesses the corresponding private key.
4. Trust: Since only the owner of the private key could have created the signature that matches the sender’s public key, the recipient can trust that the sender is authentic and hasn’t been impersonated.

In summary, authentication in public-key systems relies on the ability to verify digital signatures created with private keys using corresponding public keys. This process ensures the identity and authenticity of senders in electronic communication, providing a secure means of authentication over untrusted networks like the internet.