What is the difference between symmetric and asymmetric hashing?

Question

Accepted Answer

**Hashing** — one-way transformation. Both symmetric and asymmetric concepts apply.

**Symmetric Hashing:**
- Same key for hash and verify.
- HMAC (Hash-based Message Authentication Code).
- Shared secret.
- Fast verification.

```
HMAC:
Sender: HMAC(message, secret_key) → hash
Receiver: HMAC(message, secret_key) → verify
(Same key both sides)
```

**Asymmetric Hashing:**
- Digital signatures.
- Private key signs, public key verifies.
- Non-repudiation.
- Slower.

```
Digital Signature:
Sender: Sign(message, private_key) → signature
Receiver: Verify(message, signature, public_key)
(Different keys)
```

**Key differences:**
- **Symmetric** — shared key.
- **Asymmetric** — key pair.
- **Symmetric** — faster.
- **Asymmetric** — non-repudiation.

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