🛡️Authenticated Encryption

NEW

Also known as: AE, AEAD

A symmetric encryption approach that provides both confidentiality and integrity (authenticity) in a single construction.

DESCRIPTION

Authenticated encryption (AE) or AEAD algorithms protect data privacy and detect tampering by combining encryption with authentication. Common AEAD modes include GCM and CCM for block ciphers and ChaCha20-Poly1305 for stream ciphers. Proper nonce management is crucial for security. AE is central to modern protocols like TLS 1.3, reducing composition pitfalls associated with separate encrypt-and-MAC designs. It simplifies APIs and improves security guarantees.

ALTERNATIVE DEFINITIONS

Wikipedia

Authenticated encryption (AE) is a form of encryption which simultaneously provides confidentiality, integrity, and authenticity assurances on the data.

Highlights simultaneous provision of confidentiality and integrity/authenticity.

Source

IETF RFC 5116

This document defines a set of authenticated encryption with associated data (AEAD) algorithms.

Focuses on standardizing AEAD interfaces and algorithms for interoperability.

Source

RELATED TERMS

Confidentiality Integrity MAC Galois-Counter Mode Counter Mode with CBC-MAC Nonce Initialization Vector TLS ChaCha20-Poly1305 Rijndael

COMPETING TERMS

Encrypt-then-MAC MAC-then-Encrypt

RELATIONS

• Broader: Encryption
• Narrower: AES-GCM ChaCha20-Poly1305

KNOWLEDGE AREAS

Data Security Software Engineering

TARGET AUDIENCE

Security Architect Cybersecurity Engineer Chief Information Security Officer Software Developer Cloud Architect

EXTERNAL SOURCES

• Wikipedia - Authenticated encryption
• NIST SP 800-38D - GCM mode providing AE properties
• libsodium - AEAD usage guidance and examples

TOP QUESTIONS

Why use authenticated encryption instead of separate encryption and MAC?

AEAD avoids composition errors and offers a unified, well-analyzed primitive that simplifies secure usage and APIs.

Category: Guidance

What are common AEAD algorithms?

AES-GCM, AES-CCM, and ChaCha20-Poly1305 are widely deployed in modern protocols and libraries.

Category: Example

What is associated data (AAD)?

AAD is unencrypted data (e.g., headers) authenticated alongside ciphertext, ensuring tamper detection without confidentiality.

Category: Concept

What are common mistakes with AEAD?

Nonce reuse and weak randomness can catastrophically break security; always ensure unique nonces per key.

Category: Mistakes

How is AEAD used in TLS 1.3?

TLS 1.3 employs AEAD ciphersuites to protect record confidentiality and integrity, simplifying protocol security.

Category: Application

Is AEAD slower than basic encryption?

Overheads exist, but hardware acceleration and efficient designs make AEAD practical for high-throughput use.

Category: Performance

How do I select an AEAD mode?

Prefer widely vetted options like AES-GCM or ChaCha20-Poly1305 with strong library support and clear nonce requirements.

Category: Guidance

What if my platform lacks AES acceleration?

ChaCha20-Poly1305 often performs better on devices without AES-NI, providing strong security and speed.

Category: Guidance

How should I store nonces?

Use counters or random nonces with collision avoidance; never repeat a nonce with the same key.

Category: BestPractice