You can refer to this tutorial to install the cosign in your Jenkins machine.

You can use the wget command to install the most recent binary. In our example, the release we are installing is 2.0.0.

wget "https://github.com/sigstore/cosign/releases/download/v2.0.0/cosign-linux-amd64"

After that type the following command in order to move the Cosign binary to your bin folder:

sudo mv cosign-linux-amd64 /usr/local/bin/cosign

Next, update permissions so that Cosign can execute within your filesystem.

sudo chmod +x /usr/local/bin/cosign

Finally, verify all is done:

cosign version

You should have an outpout like that :

You can refer to this tutorial to sign your Docker images.

For exemple:

cosign sign l267t8qk.c1.de1.container-registry.ovh.net/ecommerce/stages/fuse-dashboard@sha256:ea08af50baa8659dfeef1ccc714787d4a04f2d993b8f4002008f0e94c6dcbe94

You can refer to this tutorial to sign your Docker images inside the Jenkins pipeline.