{
  "handle": "ThreeLevelCollision",
  "mechanism": "Distinguishes three collision classes and assigns specific defenses: (1) Stub Collision (Namespace exhaustion) -> Defended by full-hash verification. (2) Hash Collision (Cryptographic failure) -> Defended by SHA-256 entropy. (3) Homograph Collision (Semantic spoofing) -> Defended by Social Uptake and Reputation. A collision that cannot be resolved at its own level applies {{fail_closed}}.",
  "gloss": "Stub, hash, and homograph collisions are different threats",
  "failure_modes": [
    "Stub Confusion: Relying on 4-char stub (#a1b2) for security instead of convenience.",
    "Homograph Attack: Malicious actor mints a pattern with a trusted Handle but malicious Definition (social engineering).",
    "Pre-image Attack: Theoretical break of SHA-256 (renders Level 2 defense void)."
  ],
  "invariants": [
    "L1 Defense: Stub match is NOT verification. Full hash check is mandatory.",
    "L3 Defense: {{equivalence}} is decided by Content, not Handle. A 'spoofed' pattern is simply a different pattern with zero reputation."
  ],
  "preconditions": [
    "Sema Hashing Algorithm (SHA-256) is secure"
  ],
  "postconditions": [
    "Appropriate verification logic applied",
    "Threat level identified"
  ],
  "_meta": {
    "tier": 1,
    "ring": 2,
    "supersedes": [
      "sema:ThreeLevelCollision#mh:SHA-256:5db438e5f38882afa181ea527d06b673f64139f42390b9e795cf2ecc9efa29af",
      "sema:ThreeLevelCollision#mh:SHA-256:92b1063ea9ba8b193942d71837f055a897ace9ec4391348f56e6b1e6e11cde93",
      "sema:ThreeLevelCollision#mh:SHA-256:f9f90f76329b4b07ba1de142f14fcab8f9c5e7d901e9268a0fa03f86258a5459",
      "sema:ThreeLevelCollision#mh:SHA-256:5f6e4672403d89974278b3855f47081899347c9884b931668b71a0758db76562",
      "sema:ThreeLevelCollision#mh:SHA-256:68476a45aac32e2fd0764e409e011637b688c364cd8c75c5bb94435b98416839"
    ],
    "path": [
      "Society",
      "Protocols"
    ]
  },
  "sema_id": "sema:ThreeLevelCollision#mh:SHA-256:11d62af6f35377784694f7fc381b41369cd99da2b7480c3fe33ef8132a77f88f",
  "sema_ref": "ThreeLevelCollision#11d6",
  "sema_stub": "11d6",
  "dependencies": {
    "references": {
      "equivalence": "sema:Equivalence#mh:SHA-256:23f09a1881f50a07a5c565897f0837b3cfe4955a3b83250045f94abebf5b058c",
      "fail_closed": "sema:FailClosed#mh:SHA-256:dfbcf50c68d036ae4f18719bf59f41eddd83b5510bd60ff1326f8854240d8066"
    }
  },
  "sema_layer": "Society",
  "sema_category": "Protocols",
  "used_by": {}
}