diff --git a/.github/workflows/autobuild.yml b/.github/workflows/autobuild.yml
index 0c8c2c6..2d035c6 100644
--- a/.github/workflows/autobuild.yml
+++ b/.github/workflows/autobuild.yml
@@ -70,6 +70,8 @@ jobs:
       uses: actions/checkout@44c2b7a8a4ea60a981eaca3cf939b5f4305c123b # v4
       with:
         submodules: recursive
+    - name: install cosign
+      uses: sigstore/cosign-installer@b6fc91790eda82dbba10c76a63507d45b818c83d # 3.0.4
     - name: download artifacts
       uses: actions/download-artifact@65a9edc5881444af0b9093a5e628f2fe47ea3b2e # v4
       with:
diff --git a/.github/workflows/backbuild.yml b/.github/workflows/backbuild.yml
index 21800ab..fee0ada 100644
--- a/.github/workflows/backbuild.yml
+++ b/.github/workflows/backbuild.yml
@@ -70,6 +70,8 @@ jobs:
       uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
       with:
         submodules: recursive
+    - name: install cosign
+      uses: sigstore/cosign-installer@b6fc91790eda82dbba10c76a63507d45b818c83d # 3.0.4
     - name: download artifacts
       uses: actions/download-artifact@65a9edc5881444af0b9093a5e628f2fe47ea3b2e # v4
       with: