diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b1a9636..24e81eb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -18,12 +18,12 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v4
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
       - name: Update version number
         if: startsWith(github.ref, 'refs/tags/')
         run: sed -i -e "s/0.0.0/${GITHUB_REF##*/}/" pyproject.toml
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5
         with:
           python-version: ${{ matrix.python-version }}
       - name: install python style and linting tools
@@ -47,13 +47,13 @@ jobs:
         run: |
           python -m poetry config virtualenvs.in-project true
       - name: Upload logs on failure
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4
         if: failure()
         with:
           name: logs
           path: "*.log"
       - name: Cache the virtualenv
-        uses: actions/cache@v4
+        uses: actions/cache@ab5e6d0c87105b4c9c2047343972218f562e4319 # v4
         with:
           path: ./.venv
           key: ${{ runner.os }}-venv-${{ hashFiles('**/poetry.lock') }}
@@ -82,13 +82,13 @@ jobs:
       - name: Build
         run: poetry build
       - name: Upload dist artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4
         with:
           name: dist-${{ matrix.python-version }}
           path: dist
           if-no-files-found: error
       - name: Upload coverage HTML artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4
         with:
           name: coverage
           path: htmlcov
@@ -101,9 +101,9 @@ jobs:
     if: startsWith(github.ref, 'refs/tags/')
     steps:
       - name: Check out code
-        uses: actions/checkout@v4
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@c850b930e6ba138125429b7e5c93fc707a7f8427 # v4
         with:
           name: dist-${{ matrix.python-version }}
           path: dist