diff --git a/.github/scripts/verify-manifest.sh b/.github/scripts/verify-manifest.sh
new file mode 100755
index 000000000..1bcc5cad0
--- /dev/null
+++ b/.github/scripts/verify-manifest.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+#
+# Fails unless the manifest covers every artifact a release is expected to carry, so a release whose
+# matrix arm failed is not signed short. The counts follow the package workflow's matrix: change one,
+# change the other.
+set -euo pipefail
+
+manifest="${1:?usage: verify-manifest.sh SHA256SUMS}"
+
+if [ ! -r "$manifest" ]; then
+    echo "no readable manifest at ${manifest}" >&2
+    exit 1
+fi
+
+required=(
+    '\.dmg$:2'          # macos, x64 and arm64
+    '\.exe$:2'          # windows, x64 and arm64
+    '\.deb$:1'          # linux x64
+    '\.rpm$:1'          # linux x64
+    '\.AppImage$:2'     # linux, x64 and arm64
+)
+
+short=0
+for spec in "${required[@]}"; do
+    pattern="${spec%:*}"
+    expected="${spec##*:}"
+    actual=$(grep -cE "$pattern" "$manifest") || [ $? -eq 1 ] || exit 1
+    if [ "$actual" -ne "$expected" ]; then
+        echo "manifest carries $actual file(s) matching ${pattern}, expected ${expected}" >&2
+        short=1
+    fi
+done
+
+total=$(wc -l < "$manifest")
+if [ "$total" -ne 8 ]; then
+    echo "manifest carries $total files, expected 8" >&2
+    short=1
+fi
+
+exit "$short"
diff --git a/.github/workflows/package.yml b/.github/workflows/package.yml
index 0da88f3fa..fd47fa9f2 100644
--- a/.github/workflows/package.yml
+++ b/.github/workflows/package.yml
@@ -73,3 +73,27 @@ jobs:
             gh release upload "v${VERSION}" "${FILES[@]}" --clobber
           fi
 
+  checksums:
+    name: Publish SHA256SUMS
+    needs: package
+    # runs where a matrix arm failed too, and the manifest check below refuses a short set
+    if: ${{ !cancelled() }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+
+      - name: generate and upload SHA256SUMS
+        shell: bash
+        env:
+          GH_TOKEN: ${{ secrets.GH_TOKEN || github.token }}
+        run: |
+          set -euo pipefail
+          VERSION=$(node -p "require('./package.json').version")
+          mkdir assets
+          gh release download "v${VERSION}" --dir assets \
+            -p '*.dmg' -p '*.exe' -p '*.deb' -p '*.rpm' -p '*.AppImage'
+          ( cd assets && sha256sum * ) | LC_ALL=C sort -k 2 > SHA256SUMS
+          cat SHA256SUMS
+          ./.github/scripts/verify-manifest.sh SHA256SUMS
+          gh release upload "v${VERSION}" SHA256SUMS --clobber
diff --git a/README.md b/README.md
index c602faacc..11878eb4b 100644
--- a/README.md
+++ b/README.md
@@ -15,14 +15,27 @@ This is an unofficial fork of [Polar](https://github.com/jamaljsr/polar) that fo
 
 ## Releases
 
-Published under [Releases](https://github.com/privkeyio/polar/releases) with a signed shasums file covering every artifact:
+Published under [Releases](https://github.com/privkeyio/polar/releases) with a signed `SHA256SUMS` covering every file:
 
 ```bash
-gpg --verify polar-*-shasums.txt.asc polar-*-shasums.txt
-sha256sum -c polar-*-shasums.txt --ignore-missing
+gpg --import privkeyio-signing-key.asc
+gpg --verify SHA256SUMS.asc SHA256SUMS
+sha256sum --ignore-missing -c SHA256SUMS
 ```
 
-The signing key is `A47D 99B6 DB0D 715D 40C5 9A20 23AE 8A8E A7E2 4E38`.
+Signed by Kyle Santiago <kyle@privkey.io>, key `A47D99B6DB0D715D40C59A2023AE8A8EA7E24E38`.
+
+The macOS builds are not notarized and the Windows installers are not Authenticode signed, so both are reported as untrusted on first launch. Verify `SHA256SUMS` first, because clearing quarantine removes the check that would otherwise stop a tampered download:
+
+```bash
+xattr -dr com.apple.quarantine "/Applications/Polar BLAKE2b.app"
+```
+
+The node images are built by the `Images` workflow from the Dockerfiles in [docker](docker), each pinned to a signed checksum file or, for LND, a source commit, as listed in [docker/README.md](docker/README.md).
+
+## Reporting issues
+
+Use the [Issues](https://github.com/privkeyio/polar/issues) tab for problems specific to this fork. Anything else belongs [upstream](https://github.com/jamaljsr/polar/issues).
 
 ---