AES-256-GCM is an authenticated encryption algorithm that provides both confidentiality and integrity using a 256-bit key with Galois/Counter Mode.
AES-256-GCM
AES-256-GCM is an authenticated encryption algorithm that provides both confidentiality and integrity using a 256-bit key with Galois/Counter Mode.
Why It Matters
AES-256-GCM is the gold standard for symmetric encryption, recommended by NIST (SP 800-38D) and required by most compliance frameworks. It ensures that encrypted data cannot be read or tampered with without the correct key.
How It Works
AES-256-GCM combines AES encryption in counter mode with a Galois MAC for authentication. Each encryption operation uses a unique nonce (IV) and produces ciphertext plus an authentication tag. Decryption verifies the tag before returning plaintext, ensuring data integrity.
Best Practices
- Never reuse a nonce with the same key
- Generate nonces using a cryptographically secure random generator
- Store the nonce alongside the ciphertext (it's not secret)
- Use a proper key derivation function for key generation
Common Mistakes
- Reusing nonces (catastrophic security failure)
- Using ECB mode instead of GCM
- Encrypting data but not verifying the authentication tag on decryption
How ShieldKey Helps
ShieldKey encrypts every stored API key using AES-256-GCM. Keys are only decrypted in memory during request proxying and are never stored or logged in plaintext.
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Is AES-256-GCM secure?
Yes. AES-256-GCM is recommended by NIST and is considered secure against all known attacks when used correctly (unique nonces, proper key management). It provides both encryption and authentication.