Walk through how Alice sends Bob an encrypted message with asymmetric crypto. Which keys appear in c = E(m, pk_Bob) and m = D(c, sk_Bob)?

Alice encrypts the message with Bob's public key; Bob decrypts the ciphertext with his own private key.

* Confidentiality flows to the recipient's keys: encrypt with pk_Bob, decrypt with sk_Bob. *

1. c = E(m, pk_Bob) — Alice takes plaintext m and encrypts it with Bob's public key → ciphertext c.
2. Alice sends c to Bob over the network.
3. m = D(c, sk_Bob) — Bob decrypts c with his own private key (sk_Bob) → recovers m.

Only Bob's private key can reverse something locked with Bob's public key, so even if an eavesdropper grabs c, they can't read it.

Tip: E = Encrypt, D = Decrypt, pk = public key, sk = secret/private key. The subscript always points to Bob, because the message is for Bob — confidentiality is the recipient's keys.

Go deeper:

• Public-key cryptography — Encryption (Wikipedia) — the same encrypt-to-recipient's-public-key exchange, with worked examples.