diff --git a/.github/workflows/assert-contents.sh b/.github/workflows/assert-contents.sh
new file mode 100644
index 0000000..ebefdfb
--- /dev/null
+++ b/.github/workflows/assert-contents.sh
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+echo "Unzipping version from NuGet"
+ls from-nuget.nupkg
+mkdir from-nuget && cp from-nuget.nupkg from-nuget/zip.zip && cd from-nuget && unzip zip.zip && rm zip.zip && cd - || exit 1
+
+echo "Unzipping version from local build"
+ls packed/
+mkdir from-local && cp packed/*.nupkg from-local/zip.zip && cd from-local && unzip zip.zip && rm zip.zip && cd - || exit 1
+
+cd from-local && find . -type f -exec sha256sum {} \; | sort > ../from-local.txt && cd .. || exit 1
+cd from-nuget && find . -type f -and -not -name '.signature.p7s' -exec sha256sum {} \; | sort > ../from-nuget.txt && cd .. || exit 1
+
+diff from-local.txt from-nuget.txt
diff --git a/.github/workflows/dotnet.yaml b/.github/workflows/dotnet.yaml
index 594b906..2ef2828 100644
--- a/.github/workflows/dotnet.yaml
+++ b/.github/workflows/dotnet.yaml
@@ -221,11 +221,53 @@ jobs:
     steps:
       - run: echo "All required checks complete."
 
-  nuget-publish:
+  attestation-attribute:
+    runs-on: ubuntu-latest
+    needs: [all-required-checks-complete]
+    if: ${{ !github.event.repository.fork && github.ref == 'refs/heads/main' }}
+    permissions:
+      id-token: write
+      attestations: write
+      contents: read
+    steps:
+      - name: Download NuGet artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: nuget-package-attribute
+          path: packed
+      - name: Attest Build Provenance
+        uses: actions/attest-build-provenance@897ed5eab6ed058a474202017ada7f40bfa52940 # v1.0.0
+        with:
+          subject-path: "packed/*.nupkg"
+
+  attestation-plugin:
+    runs-on: ubuntu-latest
+    needs: [all-required-checks-complete]
+    if: ${{ !github.event.repository.fork && github.ref == 'refs/heads/main' }}
+    permissions:
+      id-token: write
+      attestations: write
+      contents: read
+    steps:
+      - name: Download NuGet artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: nuget-package-plugin
+          path: packed
+      - name: Attest Build Provenance
+        uses: actions/attest-build-provenance@897ed5eab6ed058a474202017ada7f40bfa52940 # v1.0.0
+        with:
+          subject-path: "packed/*.nupkg"
+
+  nuget-publish-attribute:
     runs-on: ubuntu-latest
     if: ${{ !github.event.repository.fork && github.ref == 'refs/heads/main' }}
     needs: [all-required-checks-complete]
     environment: main-deploy
+    permissions:
+      id-token: write
+      attestations: write
+      contents: read
     steps:
       - uses: actions/checkout@v4
       - name: Install Nix
@@ -233,20 +275,73 @@ jobs:
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
-      - name: Download NuGet artifact (plugin)
-        uses: actions/download-artifact@v4
-        with:
-          name: nuget-package-plugin
-          path: packed-plugin
-      - name: Publish to NuGet (plugin)
-        run: nix develop --command dotnet nuget push "packed-plugin/WoofWare.Myriad.Plugins.*.nupkg" --api-key ${{ secrets.NUGET_API_KEY }} --source https://api.nuget.org/v3/index.json --skip-duplicate
-      - name: Download NuGet artifact (attribute)
+      - name: Download NuGet artifact
         uses: actions/download-artifact@v4
         with:
           name: nuget-package-attribute
-          path: packed-attribute
-      - name: Publish to NuGet (attribute)
-        run: nix develop --command dotnet nuget push "packed-attribute/WoofWare.Myriad.Plugins.Attributes.*.nupkg" --api-key ${{ secrets.NUGET_API_KEY }} --source https://api.nuget.org/v3/index.json --skip-duplicate
+          path: packed
+      - name: Publish to NuGet
+        id: publish-success
+        env:
+          NUGET_API_KEY: ${{ secrets.NUGET_API_KEY }}
+        run: 'nix develop --command bash ./.github/workflows/nuget-push.sh "packed/WoofWare.Myriad.Plugins.Attributes.*.nupkg"'
+      - name: Wait for availability
+        if: steps.publish-success.outputs.result == 'published'
+        env:
+          PACKAGE_VERSION: ${{ steps.publish-success.outputs.version }}
+        run: 'echo "$PACKAGE_VERSION" && while ! curl -L --fail -o from-nuget.nupkg "https://www.nuget.org/api/v2/package/WoofWare.Myriad.Plugins.Attributes/$PACKAGE_VERSION" ; do sleep 10; done'
+      # Astonishingly, NuGet.org considers it to be "more secure" to tamper with my package after upload (https://devblogs.microsoft.com/nuget/introducing-repository-signatures/).
+      # So we have to *re-attest* it after it's uploaded. Mind-blowing.
+      - name: Assert package contents
+        if: steps.publish-success.outputs.result == 'published'
+        run: 'bash ./.github/workflows/assert-contents.sh'
+      - name: Attest Build Provenance
+        if: steps.publish-success.outputs.result == 'published'
+        uses: actions/attest-build-provenance@897ed5eab6ed058a474202017ada7f40bfa52940 # v1.0.0
+        with:
+          subject-path: "from-nuget.nupkg"
+
+  nuget-publish-plugin:
+    runs-on: ubuntu-latest
+    if: ${{ !github.event.repository.fork && github.ref == 'refs/heads/main' }}
+    needs: [all-required-checks-complete]
+    environment: main-deploy
+    permissions:
+      id-token: write
+      attestations: write
+      contents: read
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@V27
+        with:
+          extra_nix_config: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+      - name: Download NuGet artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: nuget-package-plugin
+          path: packed
+      - name: Publish to NuGet
+        id: publish-success
+        env:
+          NUGET_API_KEY: ${{ secrets.NUGET_API_KEY }}
+        run: 'nix develop --command bash ./.github/workflows/nuget-push.sh "packed/WoofWare.Myriad.Plugins.*.nupkg"'
+      - name: Wait for availability
+        if: steps.publish-success.outputs.result == 'published'
+        env:
+          PACKAGE_VERSION: ${{ steps.publish-success.outputs.version }}
+        run: 'echo "$PACKAGE_VERSION" && while ! curl -L --fail -o from-nuget.nupkg "https://www.nuget.org/api/v2/package/WoofWare.Myriad.Plugins/$PACKAGE_VERSION" ; do sleep 10; done'
+      # Astonishingly, NuGet.org considers it to be "more secure" to tamper with my package after upload (https://devblogs.microsoft.com/nuget/introducing-repository-signatures/).
+      # So we have to *re-attest* it after it's uploaded. Mind-blowing.
+      - name: Assert package contents
+        if: steps.publish-success.outputs.result == 'published'
+        run: 'bash ./.github/workflows/assert-contents.sh'
+      - name: Attest Build Provenance
+        if: steps.publish-success.outputs.result == 'published'
+        uses: actions/attest-build-provenance@897ed5eab6ed058a474202017ada7f40bfa52940 # v1.0.0
+        with:
+          subject-path: "from-nuget.nupkg"
 
   github-release-plugin:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/nuget-push.sh b/.github/workflows/nuget-push.sh
new file mode 100644
index 0000000..edc170d
--- /dev/null
+++ b/.github/workflows/nuget-push.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+
+SOURCE_NUPKG=$(find . -type f -name '*.nupkg')
+
+PACKAGE_VERSION=$(basename "$SOURCE_NUPKG" | rev | cut -d '.' -f 2-4 | rev)
+
+echo "version=$PACKAGE_VERSION" >> "$GITHUB_OUTPUT"
+
+tmp=$(mktemp)
+
+if ! dotnet nuget push "$SOURCE_NUPKG" --api-key "$NUGET_API_KEY" --source https://api.nuget.org/v3/index.json > "$tmp" ; then
+    cat "$tmp"
+    if grep 'already exists and cannot be modified' "$tmp" ; then
+        echo "result=skipped" >> "$GITHUB_OUTPUT"
+        exit 0
+    else
+        echo "Unexpected failure to upload"
+        exit 1
+    fi
+fi
+
+cat "$tmp"
+
+echo "result=published" >> "$GITHUB_OUTPUT"