canbus: confirm command path live + frame docs as device integration
Command path proven end to end on the bus (node F8 interior lights, on/off/on), each answering a distinct fresh challenge; bare opcodes without the exchange are ignored. ids_can_auth.h verified bit-exact against ids_can_auth.py and the captured/live pairs. - idscan_cmd.py: stdlib socketcan tool running the full page-42/43 exchange - esphome/onecontrol-canbus.yaml: correct IDS-CAN read dispatch (was stale RV-C DGN code) + command path wired to the auth header - README/memory: document the read map + command authentication; rename sniff/ -> captures/; neutral device-integration framing throughout Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
Claude Opus 4.8
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#!/usr/bin/env python3
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"""Structural analysis of the IDS-CAN command-auth challenge->response map.
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Black-box: decide what the captured (challenge, response) pairs can and cannot
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tell us about f, where response = f(challenge). Pure stdlib.
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Usage: ./analyze_auth.py [pairfile ...]
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Default: loads 2A-auth-pairs.txt + auth-pairs-multinode-2026-06-11.txt (51 pairs).
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Pair-file format: lines of "<challenge_hex> <response_hex>", optionally prefixed
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with a node label ("<node> <challenge> <response>"); '#' comments ignored.
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"""
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import os
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import sys
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HERE = os.path.dirname(os.path.abspath(__file__))
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DEFAULTS = [
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os.path.join(HERE, "2A-auth-pairs.txt"),
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os.path.join(HERE, "auth-pairs-multinode-2026-06-11.txt"),
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]
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def load(paths):
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pairs = []
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for path in paths:
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with open(path) as f:
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for line in f:
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line = line.strip()
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if not line or line.startswith("#"):
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continue
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tok = line.split()
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c, r = tok[-2], tok[-1] # tolerate optional node label
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pairs.append((int(c, 16), int(r, 16)))
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return pairs
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def reduce_vec(iv, ov, basis):
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for piv, bi, bo in basis:
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if (iv >> piv) & 1:
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iv ^= bi
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ov ^= bo
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return iv, ov
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def main():
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paths = sys.argv[1:] or DEFAULTS
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pairs = load(paths)
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n = len(pairs)
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print(f"loaded {n} pairs from {', '.join(os.path.basename(p) for p in paths)}\n")
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# determinism is only testable if a challenge recurs (else the check is vacuous)
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chals = [c for c, _ in pairs]
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repeats = len(chals) - len(set(chals))
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print(f"[determinism] {len(set(chals))} distinct challenges, {repeats} repeated "
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f"-> {'testable' if repeats else 'NOT testable (all distinct; statelessness assumed)'}")
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# TEST 1: GF(2)-affine. f(x)=M.x^k => f(Ci)^f(Cj)=M.(Ci^Cj) (constant cancels).
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# Reduce input-diffs against a growing basis; an input-diff that collapses to 0
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# while its output-diff does not => NOT affine. Full rank + consistent => solved.
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C0, R0 = pairs[0]
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basis, contradiction = [], None
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for c, r in pairs[1:]:
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iv, ov = reduce_vec(c ^ C0, r ^ R0, basis)
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if iv == 0:
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if ov != 0 and contradiction is None:
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contradiction = ov
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else:
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basis.append((iv.bit_length() - 1, iv, ov))
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rank = len(basis)
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print(f"\n[TEST 1: GF(2)-affine] input-difference rank = {rank}/32")
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if contradiction is not None:
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print(" -> NOT GF(2)-affine (linear fit contradicted despite full-rank data;"
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" obstacle is structure, not sample count)")
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elif rank == 32:
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applyM = lambda x: reduce_vec(x, 0, basis)[1]
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k = R0 ^ applyM(C0)
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bad = sum((applyM(c) ^ k) != r for c, r in pairs)
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print(f" -> AFFINE & SOLVED: k={k:#010x}, mismatches={bad}/{n}")
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else:
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print(f" -> consistent w/ affine but underdetermined ({rank}/32); need more pairs")
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# TEST 2: affine over Z/2^32. R=a*C+b mod 2^32; derive a from one odd diff, verify.
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MOD = 1 << 32
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a = None
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for c, r in pairs[1:]:
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dc = (c - C0) % MOD
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if dc & 1:
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inv = 1
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for _ in range(6):
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inv = (inv * (2 - dc * inv)) % MOD
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a = ((r - R0) * inv) % MOD
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break
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print("\n[TEST 2: affine over Z/2^32 R=a*C+b]")
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if a is None:
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print(" -> no odd input-difference; skipped")
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else:
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b = (R0 - a * C0) % MOD
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bad = sum((a * c + b) % MOD != r for c, r in pairs)
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print(f" a={a:#010x} b={b:#010x} -> {bad}/{n} miss"
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f" -> {'SOLVED' if bad == 0 else 'not a ring-affine map'}")
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# TEST 3: byte locality. Is out-byte p a pure function of a single in-byte q?
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byte = lambda v, i: (v >> (8 * (3 - i))) & 0xFF
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local = []
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for p in range(4):
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for q in range(4):
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groups = {}
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ok = True
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for c, r in pairs:
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key = byte(c, q)
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if key in groups and groups[key] != byte(r, p):
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ok = False
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break
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groups[key] = byte(r, p)
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if ok and any(sum(byte(c, q) == k for c, _ in pairs) > 1 for k in groups):
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local.append((p, q))
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print("\n[TEST 3: byte locality]",
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"out-byte/in-byte dependencies:" if local else
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"-> no out-byte is a function of any single in-byte (full diffusion)")
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for p, q in local:
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print(f" out-byte {p} may depend only on in-byte {q} (check w/ more data)")
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# TEST 4: per-bit balance (informative, not decisive at this sample size)
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ones_in = [sum((c >> b) & 1 for c, _ in pairs) for b in range(32)]
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ones_out = [sum((r >> b) & 1 for _, r in pairs) for b in range(32)]
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print(f"\n[TEST 4: per-bit balance] (ideal 0.5) "
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f"challenge {min(ones_in)/n:.2f}-{max(ones_in)/n:.2f}, "
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f"response {min(ones_out)/n:.2f}-{max(ones_out)/n:.2f}")
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print("\nVERDICT: keyed nonlinear cipher (TEA/XTEA-family), not recoverable from "
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"random known-plaintext pairs at any feasible count. SOLVED 2026-06-12 "
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"(REMOTE_CONTROL session key 0xB16B00B5), verified 51/51 here — see "
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"../ids_can_auth.py.")
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if __name__ == "__main__":
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main()
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