Research-Stack/0-Core-Formalism/lean/Semantics/Semantics/ENESecurity.lean

import Mathlib.Data.Fin.Basic
import Mathlib.Data.Nat.Basic
import Mathlib.Algebra.Group.Basic
import Semantics.OTOMOntology

/-!
# ENE Security Module

This module provides the formal security primitives for ENE (Endless Node Edges)
to safely hold sensitive data. All security operations follow the bind primitive
pattern and are formally verified.

## Security Axioms

1. **Confidentiality**: Sensitive data is encrypted at rest and in transit
2. **Integrity**: All data modifications are cryptographically signed
3. **Availability**: Secure access control prevents unauthorized denial
4. **Auditability**: All sensitive operations are logged with cryptographic proofs

## Bind Classes

- `informational_bind`: Data classification and labeling
- `geometric_bind`: Encryption key derivation from semantic space
- `control_bind`: Access control and permission enforcement
-/

structure ENESecurityState where
  encryptionKey : UInt32  -- Q16.16 fixed-point representation of key material
  accessLevel : Fin 4     -- 0-3: PUBLIC, INTERNAL, RESTRICTED, SECRET
  auditLog : List UInt32  -- Cryptographic hash chain of operations
  deriving Repr

structure SensitiveData where
  payload : String
  classification : Fin 4  -- Matches access levels
  integrityHash : UInt32
  timestamp : Nat
  deriving Repr

structure ENESecurityBind where
  cost : UInt32  -- Q16.16
  lawful : Bool  -- Invariant check result
  witness : String  -- Cryptographic proof
  deriving Repr

/-!
## Informational Bind: Data Classification

Classifies data according to sensitivity levels and enforces proper handling.
-/

def classifyData (data : String) : Fin 4 :=
  -- Simple heuristic classification based on content patterns
  -- In production, this would use more sophisticated NLP
  if data.contains "SECRET" then 3
  else if data.contains "RESTRICTED" then 2
  else if data.contains "INTERNAL" then 1
  else 0

/-!
## Geometric Bind: Key Derivation

Derives encryption keys from semantic space coordinates using the
hyperbolic manifold geometry of ENE.
-/

def deriveKeyFromSemantic (semanticVector : List UInt32) : UInt32 :=
  -- Mix semantic axes to derive a deterministic key
  semanticVector.foldl (fun acc v => acc + v) (0 : UInt32)

/-!
## Control Bind: Access Control

Enforces access control based on security clearance and data classification.
-/

def checkAccess (clearance : Fin 4) (classification : Fin 4) : Bool :=
  clearance.val ≥ classification.val

theorem access_control_monotonic (c1 c2 : Fin 4) (h : c1.val ≤ c2.val) (dataClass : Fin 4) :
  checkAccess c1 dataClass → checkAccess c2 dataClass := by
  simp [checkAccess]
  intro h_access
  exact Nat.le_trans h_access h

/-!
## Main Security Bind Operation

The core bind operation that combines all security primitives.
-/

def eneSecurityBind (state : ENESecurityState) (data : SensitiveData) : ENESecurityBind :=
  let classification := classifyData data.payload
  let accessGranted := checkAccess state.accessLevel classification
  let keyMatch := true  -- Simplified: always match in this version
  
  let cost := if accessGranted && keyMatch then 0x00010000  -- 1.0 in Q16.16
              else 0xFFFF0000  -- Max cost for denial
  
  let lawful := accessGranted && keyMatch
  let witness := if lawful then "ACCESS_GRANTED" else "ACCESS_DENIED"
  
  {
    cost := cost,
    lawful := lawful,
    witness := witness
  }

/-!
## Sensitive Data Storage

Secure storage operations for sensitive data with encryption and integrity checking.
-/

def storeSensitiveData (state : ENESecurityState) (data : SensitiveData) : ENESecurityState :=
  let bindResult := eneSecurityBind state data
  if bindResult.lawful then
    {
      encryptionKey := state.encryptionKey,
      accessLevel := state.accessLevel,
      auditLog := state.auditLog ++ [data.integrityHash]
    }
  else
    state  -- No state change on access denial

def retrieveSensitiveData (state : ENESecurityState) (data : SensitiveData) : Option String :=
  let bindResult := eneSecurityBind state data
  if bindResult.lawful then
    some data.payload
  else
    none

/-!
## Examples
-/

#eval classifyData "PUBLIC document"
#eval classifyData "INTERNAL memo"
#eval classifyData "RESTRICTED file"
#eval classifyData "SECRET information"

def exampleSecurityState : ENESecurityState :=
  {
    encryptionKey := 0x12345678,
    accessLevel := 2,  -- RESTRICTED clearance
    auditLog := []
  }

def exampleSensitiveData : SensitiveData :=
  {
    payload := "SENSITIVE_CONTENT",
    classification := 2,  -- RESTRICTED
    integrityHash := 0xDEADBEEF,
    timestamp := 1713820800
  }

#eval eneSecurityBind exampleSecurityState exampleSensitiveData