TL;DR
Encryption scrambles data so only authorized parties can read it. Think of it like a lock on your data. Without the key, it's gibberish. Encryption "in transit" (HTTPS) protects data traveling over networks. Encryption "at rest" protects stored data. Modern apps should use both. AES-256 is the current standard for strong encryption.
The Simple Explanation
Encryption converts readable data (plaintext) into scrambled data (ciphertext). Only someone with the right key can convert it back. If an attacker intercepts encrypted data, they just see random characters.
Encryption Types
| Type | How It Works | Example Use |
|---|---|---|
| Symmetric | Same key encrypts and decrypts | AES-256 for data at rest |
| Asymmetric | Public key encrypts, private key decrypts | RSA for HTTPS, SSH |
In Transit vs At Rest
- In transit: Data moving over networks. HTTPS handles this.
- At rest: Data stored in databases, files, backups. Needs separate encryption.
When to Encrypt
- Credit card numbers
- Social security numbers
- Health information
- Personal identification
- API keys and secrets (though these should use secrets management)
What is the difference between encryption and hashing?
Encryption is reversible with the right key. You can decrypt encrypted data to get the original back. Hashing is one-way. You cannot reverse a hash to get the original data. Use encryption when you need to read the data later. Use hashing for passwords where you only need to verify, not retrieve.
What is encryption at rest vs in transit?
Encryption in transit protects data while it travels over networks (HTTPS does this). Encryption at rest protects data stored on disk or in databases. For full protection, you need both. Most cloud providers offer encryption at rest for databases and storage.
Do I need to encrypt data if I use HTTPS?
HTTPS encrypts data in transit, but not at rest. If someone accesses your database or server, they can read unencrypted data. For sensitive information like social security numbers, credit cards, or health data, also encrypt at rest. Many compliance requirements mandate encryption at rest.