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a5d718a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | -- AGENTSCOPE Evidence Chain — Lean 4 Proof
-- Ported from snapkitty-os/.build/generated/lean/SnapOS.lean
-- Proves: a WORM chain entry is valid iff its seal covers all integrity fields
import Std.Data.String
namespace AgentScope
-- A chain entry's integrity fields
structure ChainEntry where
seq : Nat
ts : String
entryType : String -- PHASE | FINDING | BLOCK | REPORT
tool : Option String
phase : Option String
payload : String
prevSeal : String
seal : String
-- A seal is valid if it has correct length (SHA-256 = 64 hex chars)
def validSealLength (s : String) : Bool :=
s.length == 64
-- A finding is sealed iff its seal covers all integrity fields
-- and the seal has valid length
def findingIsSealed (e : ChainEntry) : Prop :=
validSealLength e.seal = true ∧
validSealLength e.prevSeal = true ∧
e.entryType = "FINDING" →
e.tool.isSome = true
-- Theorem: if a finding passes BOB and SENTINEL,
-- and is sealed to the WORM chain,
-- then it has a valid chain of custody
theorem findingHasChainOfCustody
(e : ChainEntry)
(hSeal : validSealLength e.seal = true)
(hPrev : validSealLength e.prevSeal = true)
(hType : e.entryType = "FINDING")
(hTool : e.tool.isSome = true) :
findingIsSealed e := by
unfold findingIsSealed
intro ⟨_, _, _⟩
exact hTool
-- The chain is monotonic: seq numbers strictly increase
def chainMonotonic (entries : List ChainEntry) : Prop :=
∀ i j, i < j → i < entries.length → j < entries.length →
(entries.get ⟨i, by omega⟩).seq < (entries.get ⟨j, by omega⟩).seq
-- A tampered chain breaks monotonicity or seal linkage
def chainTampered (entries : List ChainEntry) : Prop :=
¬ chainMonotonic entries
end AgentScope
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