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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 021

AEAD (Authenticated Encryption with Associated Data)

O que é AEAD (Authenticated Encryption with Associated Data)?

AEAD (Authenticated Encryption with Associated Data)A symmetric encryption primitive that provides confidentiality, integrity, and authenticity in one operation, with the ability to bind unencrypted 'associated data' (headers, routing info) to the ciphertext's authentication tag.


Authenticated Encryption with Associated Data (AEAD) is the modern building block of symmetric cryptography. An AEAD scheme takes a key, a nonce, a plaintext, and arbitrary associated data (AD) and produces a ciphertext plus an authentication tag; on decryption it returns the plaintext only if the tag verifies, otherwise refusing. The associated data is authenticated but not encrypted, letting protocols bind unencrypted context such as packet headers, sequence numbers, or version metadata to the ciphertext without ever sending them encrypted. Compared to encrypt-then-MAC or MAC-then-encrypt compositions, AEAD eliminates whole classes of bugs (padding oracles, key reuse across MAC and cipher, ordering mistakes) and is what every modern protocol — TLS 1.3, QUIC, IPsec ESP-GCM, Signal, Noise, WireGuard, JWE — uses. The dominant AEAD schemes are AES-GCM and ChaCha20-Poly1305; nonce-misuse-resistant variants (AES-GCM-SIV) exist for use cases where the caller cannot guarantee unique nonces. Always prefer an AEAD over a homebrew encrypt-and-MAC composition.

Exemplos

  1. 01

    TLS 1.3 encrypts each record with AES-128-GCM or ChaCha20-Poly1305, using the record header bytes as associated data.

  2. 02

    A protocol stores per-document encrypted blobs in a database; the document ID is passed as AD so an attacker cannot swap ciphertexts between documents without breaking the tag.

Perguntas frequentes

O que é AEAD (Authenticated Encryption with Associated Data)?

A symmetric encryption primitive that provides confidentiality, integrity, and authenticity in one operation, with the ability to bind unencrypted 'associated data' (headers, routing info) to the ciphertext's authentication tag. Pertence à categoria Criptografia da cibersegurança.

O que significa AEAD (Authenticated Encryption with Associated Data)?

A symmetric encryption primitive that provides confidentiality, integrity, and authenticity in one operation, with the ability to bind unencrypted 'associated data' (headers, routing info) to the ciphertext's authentication tag.

Como funciona AEAD (Authenticated Encryption with Associated Data)?

Authenticated Encryption with Associated Data (AEAD) is the modern building block of symmetric cryptography. An AEAD scheme takes a key, a nonce, a plaintext, and arbitrary associated data (AD) and produces a ciphertext plus an authentication tag; on decryption it returns the plaintext only if the tag verifies, otherwise refusing. The associated data is authenticated but not encrypted, letting protocols bind unencrypted context such as packet headers, sequence numbers, or version metadata to the ciphertext without ever sending them encrypted. Compared to encrypt-then-MAC or MAC-then-encrypt compositions, AEAD eliminates whole classes of bugs (padding oracles, key reuse across MAC and cipher, ordering mistakes) and is what every modern protocol — TLS 1.3, QUIC, IPsec ESP-GCM, Signal, Noise, WireGuard, JWE — uses. The dominant AEAD schemes are AES-GCM and ChaCha20-Poly1305; nonce-misuse-resistant variants (AES-GCM-SIV) exist for use cases where the caller cannot guarantee unique nonces. Always prefer an AEAD over a homebrew encrypt-and-MAC composition.

Como se defender contra AEAD (Authenticated Encryption with Associated Data)?

As defesas contra AEAD (Authenticated Encryption with Associated Data) costumam combinar controles técnicos e práticas operacionais, conforme detalhado na definição acima.

Quais são outros nomes para AEAD (Authenticated Encryption with Associated Data)?

Nomes alternativos comuns: Authenticated encryption, AEAD scheme.

Termos relacionados

Veja também