diff --git a/deploy/bundle/build_offline_bundle.sh b/deploy/bundle/build_offline_bundle.sh
index 54d949f..a309730 100755
--- a/deploy/bundle/build_offline_bundle.sh
+++ b/deploy/bundle/build_offline_bundle.sh
@@ -116,6 +116,41 @@ cp "$REPO_ROOT/deploy/bundle/install_offline.sh"            "$STAGE/"
 cp "$REPO_ROOT/docs/pilot-runbook.md"                       "$STAGE/docs/" 2>/dev/null || true
 chmod +x "$STAGE/install_offline.sh"
 
+# Supply-chain integrity (air-gap: the target can't reach PyPI to re-resolve, so pin + hash here).
+#   SHA256SUMS       — sha256 of every wheel + model; install_offline verifies before installing.
+#   requirements.lock — exact name==version of every bundled wheel, for a reproducible rebuild.
+#   sbom.json        — CycloneDX component list (name, version, pypi purl, sha256).
+echo ">> generating integrity manifest (SHA256SUMS, requirements.lock, sbom.json)"
+( cd "$STAGE" && sha256sum wheelhouse/*.whl models/* > SHA256SUMS )
+
+: > "$STAGE/requirements.lock"
+{
+  printf '{\n  "bomFormat": "CycloneDX",\n  "specVersion": "1.5",\n  "version": 1,\n  "components": [\n'
+  sep=""
+  for whl in "$WHEELHOUSE"/*.whl; do
+    [ -e "$whl" ] || continue
+    base="$(basename "$whl")"
+    name="$(echo "$base" | cut -d- -f1)"       # wheel: {name}-{version}-{pyabi}-...-{plat}.whl
+    ver="$(echo "$base" | cut -d- -f2)"
+    sum="$(sha256sum "$whl" | cut -d' ' -f1)"
+    echo "${name}==${ver}" >> "$STAGE/requirements.lock"
+    printf '%s    {"type":"library","name":"%s","version":"%s","purl":"pkg:pypi/%s@%s","hashes":[{"alg":"SHA-256","content":"%s"}]}' \
+      "$sep" "$name" "$ver" "$name" "$ver" "$sum"
+    sep=$',\n'
+  done
+  printf '\n  ]\n}\n'
+} > "$STAGE/sbom.json"
+sort -u -o "$STAGE/requirements.lock" "$STAGE/requirements.lock"
+
+# Optional detached GPG signature over the integrity file. The air-gap target verifies via
+# SHA256SUMS regardless; a signature adds provenance when a signing key exists on the build box.
+if [ -n "${SIGN_KEY:-}" ]; then
+  gpg --local-user "$SIGN_KEY" --armor --detach-sign --output "$STAGE/SHA256SUMS.asc" "$STAGE/SHA256SUMS"
+  echo ">> signed SHA256SUMS with key $SIGN_KEY -> SHA256SUMS.asc"
+else
+  echo ">> NOTE: SHA256SUMS is unsigned (set SIGN_KEY=<gpg-id> to add a detached signature)."
+fi
+
 # Which pose backends this bundle can actually run, so the operator knows before it crosses the
 # air gap. Hailo needs the HEF (present) + system hailo_platform on the Pi; MoveNet needs the ONNX.
 HAS_ONNX=no; [ -f "$STAGE/models/movenet_lightning.onnx" ] && HAS_ONNX=yes
@@ -126,6 +161,7 @@ HAS_ONNX=no; [ -f "$STAGE/models/movenet_lightning.onnx" ] && HAS_ONNX=yes
   echo "target_arch: $TARGET_ARCH"
   echo "hailo_arch: $HAILO_ARCH"
   echo "pose_backends: hailo (yolov8s_pose.hef)$([ "$HAS_ONNX" = yes ] && echo ', movenet (movenet_lightning.onnx)')"
+  echo "integrity: SHA256SUMS (verified on install), requirements.lock, sbom.json$([ -f "$STAGE/SHA256SUMS.asc" ] && echo ', SHA256SUMS.asc (signed)')"
   echo "models:"
   ls -1 "$STAGE/models"
   echo "wheels:"
diff --git a/deploy/bundle/install_offline.sh b/deploy/bundle/install_offline.sh
index 3075f8e..ab5ccbc 100755
--- a/deploy/bundle/install_offline.sh
+++ b/deploy/bundle/install_offline.sh
@@ -46,7 +46,21 @@ cp "$HERE/models/"*.hef  "$PREFIX/models/" 2>/dev/null || true
 cp "$HERE/models/"*.onnx "$PREFIX/models/" 2>/dev/null || true
 cp "$HERE/docs/"*.md "$PREFIX/docs/" 2>/dev/null || true
 
-echo ">> [3/6] python venv + offline wheel install (--no-index)"
+echo ">> [3/6] verify bundle integrity + python venv + offline wheel install (--no-index)"
+# Supply-chain: verify every bundled wheel + model against the build-time SHA256SUMS BEFORE
+# installing anything. A truncated transfer or a tampered wheel must fail here, loudly, not
+# install silently. Older bundles without the file are allowed through with a warning.
+if [ -f "$HERE/SHA256SUMS" ]; then
+  ( cd "$HERE" && sha256sum -c SHA256SUMS ) \
+    || { echo "ERROR: bundle integrity check failed (SHA256SUMS mismatch) — refusing to install." >&2; exit 1; }
+  if [ -f "$HERE/SHA256SUMS.asc" ]; then
+    gpg --verify "$HERE/SHA256SUMS.asc" "$HERE/SHA256SUMS" 2>/dev/null \
+      && echo "   -> SHA256SUMS signature verified" \
+      || echo "   -> WARNING: SHA256SUMS.asc present but signature did not verify (missing/again untrusted key?)." >&2
+  fi
+else
+  echo "   -> WARNING: no SHA256SUMS in bundle; skipping integrity check (rebuild with a newer build_offline_bundle.sh)." >&2
+fi
 # --system-site-packages so the venv can import the Pi SYSTEM packages that are NOT
 # pip-installable: hailo_platform (HailoRT, apt: hailo-all) for POSE_BACKEND=hailo, and
 # picamera2 (apt: python3-picamera2) for CAMERA_BACKEND=csi. The wheelhouse install
diff --git a/docs/delivery-audit.md b/docs/delivery-audit.md
index b18d565..4ccbb9c 100644
--- a/docs/delivery-audit.md
+++ b/docs/delivery-audit.md
@@ -216,9 +216,16 @@ misconfig/degradation fail LOUD.
   `install_offline.sh` copied only `*.onnx` so a bundled HEF never reached `$PREFIX/models` for the
   backend gate to find (now copies `*.hef` too). MANIFEST lists models + available pose_backends.
   Tests: fetches/stages HEF, MoveNet optional, installer copies the HEF.
-- [ ] **P5-4 [M]** `deploy/bundle/build_offline_bundle.sh:28` — pip deps unpinned, no digests,
+- [x] **P5-4 [M]** `deploy/bundle/build_offline_bundle.sh:28` — pip deps unpinned, no digests,
   MANIFEST has no hashes, bundle unsigned; spec requires SHA256/GPG + SBOM. **Fix:** pin +
   hash + manifest digests.
+  DONE — build emits `SHA256SUMS` (sha256 of every wheel + model), `requirements.lock` (exact
+  `name==version` pins for a reproducible rebuild), and `sbom.json` (CycloneDX 1.5: name, version,
+  pypi purl, sha256). Optional detached GPG signature via `SIGN_KEY` → `SHA256SUMS.asc`.
+  `install_offline.sh` runs `sha256sum -c SHA256SUMS` (and verifies the signature if present)
+  BEFORE any pip install, hard-failing on mismatch. Generation logic verified end-to-end on a
+  synthetic stage (valid JSON, `sha256sum -c` passes). Tests lock the manifest + the install-time
+  check.
 - [x] **P5-5 [H]** `deploy/systemd/move-detect-edge.service:46` `OFF-HW` — `DeviceAllow` omits
   `/dev/media*` and `/dev/dma_heap`; picamera2/libcamera on Pi 5 needs them, so the CSI camera
   is denied by the unit's own policy. **Fix:** add the device classes; verify on hardware.
diff --git a/tests/test_deploy_artifacts.py b/tests/test_deploy_artifacts.py
index 8e24e24..59f2796 100644
--- a/tests/test_deploy_artifacts.py
+++ b/tests/test_deploy_artifacts.py
@@ -243,3 +243,23 @@ def test_offline_installer_copies_the_hef_into_place():
     # install_offline used to copy only *.onnx, so a HEF in the bundle never reached
     # $PREFIX/models and the Hailo backend gate ([5/6]) could never see it.
     assert 'cp "$HERE/models/"*.hef' in sh
+
+
+def test_offline_bundle_emits_pinned_integrity_manifest():
+    with open(BUILD_OFFLINE, encoding="utf-8") as f:
+        sh = f.read()
+    # Air-gap supply-chain: the target can't re-resolve from PyPI, so the build must pin exact
+    # versions, hash every artifact, and ship an SBOM. GPG signing is optional (SIGN_KEY).
+    assert "sha256sum wheelhouse/*.whl models/* > SHA256SUMS" in sh
+    assert "requirements.lock" in sh          # exact name==version pins for a reproducible rebuild
+    assert "sbom.json" in sh
+    assert "CycloneDX" in sh
+    assert 'if [ -n "${SIGN_KEY:-}" ]; then' in sh  # optional detached signature
+
+
+def test_offline_installer_verifies_integrity_before_install():
+    with open(INSTALL_OFFLINE, encoding="utf-8") as f:
+        sh = f.read()
+    # A truncated/tampered wheel must fail loudly BEFORE any pip install, not install silently.
+    assert "sha256sum -c SHA256SUMS" in sh
+    assert "integrity check failed" in sh