{
  "slug": "replay-attack",
  "term": "Replay attack",
  "aliases": [],
  "definition": "A replay attack reuses previously valid data to induce acceptance in an unauthorized context.",
  "note": "RFC 4949 describes replay for valid transmissions; the storage counterpart can restore an older authenticated block without forging its tag. Broz and colleagues explicitly exclude this threat from their 2018 sector-encryption design. [rfc4949] [broz2018] Legitimate journal replay during crash recovery is not, by itself, an attack. [hesela-freshness]",
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-15",
  "related": [
    "rollback-protection",
    "authenticated-encryption",
    "cryptographic-nonce",
    "dm-integrity"
  ],
  "citations": [
    {
      "id": "rfc4949",
      "title": "RFC 4949: Internet Security Glossary, Version 2 (2007), replay attack; informational glossary, not an Internet Standard",
      "url": "https://www.rfc-editor.org/rfc/rfc4949.html",
      "accessed": "2026-10-15"
    },
    {
      "id": "broz2018",
      "title": "Broz, Patocka and Matyas: Practical cryptographic data integrity protection with full disk encryption (extended version), 2018, section 2.4",
      "url": "https://arxiv.org/pdf/1807.00309v1",
      "accessed": "2026-10-15"
    },
    {
      "id": "hesela-freshness",
      "title": "Hesela: A trusted root still needs a version policy",
      "url": "https://hesela.com/analyses/checksums-identity-and-lost-writes/#verity-freshness",
      "accessed": "2026-10-15"
    }
  ]
}