---
slug: "ThreeLevelCollision"
name: "ThreeLevelCollision"
type: "Protocols"
layer: "Society"
ref: "ThreeLevelCollision#11d6"
sema_id: "sema:ThreeLevelCollision#mh:SHA-256:11d62af6f35377784694f7fc381b41369cd99da2b7480c3fe33ef8132a77f88f"
tags: ["Society","Protocols"]
updated: 2026-11-11
mindscape: "bootstrap"
index_url: https://mindscape.pages.dev/bootstrap/index.json
url: https://mindscape.pages.dev/bootstrap/ThreeLevelCollision/
related: ["Equivalence","FailClosed"]
---

# ThreeLevelCollision

Stub, hash, and homograph collisions are different threats

Layer: Society · Category: Protocols

## 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 [FailClosed](https://mindscape.pages.dev/bootstrap/FailClosed.md).

## Invariants

- L1 Defense: Stub match is NOT verification. Full hash check is mandatory.
- L3 Defense: [Equivalence](https://mindscape.pages.dev/bootstrap/Equivalence.md) 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

## 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).

## Builds on

- [Equivalence](https://mindscape.pages.dev/bootstrap/Equivalence.md) (Infrastructure; References)
- [FailClosed](https://mindscape.pages.dev/bootstrap/FailClosed.md) (Infrastructure; References)

## Used by

—

## Identity

- Sema ID: `sema:ThreeLevelCollision#mh:SHA-256:11d62af6f35377784694f7fc381b41369cd99da2b7480c3fe33ef8132a77f88f`
- Ref: `ThreeLevelCollision#11d6`
- 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`

## Links

- [Pattern page](https://mindscape.pages.dev/bootstrap/ThreeLevelCollision/)
- [View in the interactive graph](https://mindscape.pages.dev/bootstrap/#ThreeLevelCollision)
- [JSON](https://mindscape.pages.dev/bootstrap/ThreeLevelCollision.json)
- [Index of all patterns](https://mindscape.pages.dev/bootstrap/index.json)