ci: attempt to fix DCT key

Author: buchdag

.github/workflows/build-publish-signed.yml

@@ -22,13 +22,12 @@ jobs:
           fetch-depth: 0
 
       - name: Load DCT delegation key
-        env:
-          DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE: ${{ secrets.DCT_KEY_PASSPHRASE }}
-          DCT_KEY_BASE64: ${{ secrets.DCT_KEY_BASE64 }}
         run: |
-          echo "$DCT_KEY_BASE64" | base64 -d > delegation.key
-          chmod 600 delegation.key
-          docker trust key load delegation.key --name gha
+          export DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE="${{ secrets.DCT_KEY_PASSPHRASE }}"
+          mkdir -p ~/.docker/trust/private/
+          echo "${{ secrets.DCT_KEY_BASE64 }}" | base64 -d > "~/.docker/trust/private/${{ secrets.DCT_KEY_ID }}.key"
+          chmod 600 "~/.docker/trust/private/${{ secrets.DCT_KEY_ID }}.key"
+          docker trust key load "~/.docker/trust/private/${{ secrets.DCT_KEY_ID }}.key" --name gha
 
       - name: Login to DockerHub
         uses: docker/login-action@v3
@@ -40,14 +39,13 @@ jobs:
         run: docker build -t ${{ env.IMAGE_NAME }}:${{ env.IMAGE_TAG }} .
 
       - name: Push and sign the image
-        env:
-          DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE: ${{ secrets.DCT_KEY_PASSPHRASE }}
         run: |
+          export DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE="${{ secrets.DCT_KEY_PASSPHRASE }}"
           docker trust sign ${{ env.IMAGE_NAME }}:${{ env.IMAGE_TAG }}
 
       - name: Verify the image signature
         run: |
           docker trust inspect --pretty ${{ env.IMAGE_NAME }}:${{ env.IMAGE_TAG }}
 
       - name: Remove DCT delegation key
-        run: rm delegation.key
+        run: rm "~/.docker/trust/private/${{ secrets.DCT_KEY_ID }}.key"