What is the difference between symmetric and asymmetric encryption?

Question

Accepted Answer

**Symmetric** — one key. **Asymmetric** — public/private key pair.

**Symmetric Encryption:**
- Same key for encrypt and decrypt.
- Fast, efficient.
- Key distribution problem.
- AES, DES, 3DES.

```
Symmetric:
Sender: plaintext + secret_key → ciphertext
Receiver: ciphertext + secret_key → plaintext
(Same key both sides)
```

**Asymmetric Encryption:**
- Public key encrypts, private key decrypts.
- Slower, complex.
- No key distribution problem.
- RSA, ECC, Diffie-Hellman.

```
Asymmetric:
Sender: plaintext + public_key → ciphertext
Receiver: ciphertext + private_key → plaintext
(Different keys)
```

**Key differences:**
- **Symmetric** — one key.
- **Asymmetric** — two keys.
- **Symmetric** — fast.
- **Asymmetric** — secure key exchange.

Systems Analyst: What is the difference between symmetric and asymmetric encryption?