diff --git a/ci-automation/ci_automation_common.sh b/ci-automation/ci_automation_common.sh
index ce01d55765..25e47c12df 100644
--- a/ci-automation/ci_automation_common.sh
+++ b/ci-automation/ci_automation_common.sh
@@ -175,7 +175,8 @@ function docker_image_to_buildcache() {
     local tarball="$(basename "$image")-${version}.tar.gz"
 
     $docker save "${image}":"${version}" | $PIGZ -c > "${tarball}"
-    copy_to_buildcache "containers/${version}" "${tarball}"
+    sign_artifacts "${SIGNER:-}" "${tarball}"
+    copy_to_buildcache "containers/${version}" "${tarball}"*
 }
 # --
 
@@ -299,3 +300,50 @@ function secret_to_file() {
     config_ref="/proc/${$}/fd/${fd}"
 }
 # --
+
+# Creates signatures for the passed files and directories. In case of
+# directory, all files inside are signed. Files ending with .asc or
+# .sig or .gpg are ignored, though. This function is a noop if signer
+# is empty.
+#
+# Typical use:
+#   sign_artifacts "${SIGNER}" artifact.tar.gz
+#   copy_to_buildcache "artifacts/directory" artifact.tar.gz*
+#
+# Parameters:
+#
+# 1 - signer whose key is expected to be already imported into the
+#       keyring
+# @ - files and directories to sign
+function sign_artifacts() {
+    local signer="${1}"; shift
+    # rest of the parameters are directories/files to sign
+    local to_sign=()
+    local file
+    local files
+
+    if [[ -z "${signer}" ]]; then
+        return
+    fi
+
+    for file; do
+        files=()
+        if [[ -d "${file}" ]]; then
+            readarray -d '' files < <(find "${file}" ! -type d -print0)
+        elif [[ -e "${file}" ]]; then
+            files+=( "${file}" )
+        fi
+        for file in "${files[@]}"; do
+            if [[ "${file}" =~ \.(asc|gpg|sig)$ ]]; then
+                continue
+            fi
+            to_sign+=( "${file}" )
+        done
+    done
+    for file in "${to_sign[@]}"; do
+        gpg --batch --local-user "${signer}" \
+            --output "${file}.sig" \
+            --detach-sign "${file}"
+    done
+}
+# --
diff --git a/ci-automation/packages.sh b/ci-automation/packages.sh
index be1775b0c5..a6813e280a 100644
--- a/ci-automation/packages.sh
+++ b/ci-automation/packages.sh
@@ -175,9 +175,12 @@ function _packages_build_impl() {
     docker_commit_to_buildcache "${packages_container}" "${packages_image}" "${docker_vernum}"
 
     # Publish torcx manifest and docker tarball to "images" cache so tests can pull it later.
-    copy_to_buildcache "images/${arch}/${vernum}/torcx" \
-        "${torcx_tmp}/torcx/${arch}-usr/latest/torcx_manifest.json"
-    copy_to_buildcache "images/${arch}/${vernum}/torcx" \
+    sign_artifacts "${SIGNER}" \
+        "${torcx_tmp}/torcx/${arch}-usr/latest/torcx_manifest.json" \
         "${torcx_tmp}/torcx/pkgs/${arch}-usr/docker/"*/*.torcx.tgz
+    copy_to_buildcache "images/${arch}/${vernum}/torcx" \
+        "${torcx_tmp}/torcx/${arch}-usr/latest/torcx_manifest.json"*
+    copy_to_buildcache "images/${arch}/${vernum}/torcx" \
+        "${torcx_tmp}/torcx/pkgs/${arch}-usr/docker/"*/*.torcx.tgz*
 }
 # --
diff --git a/ci-automation/push_pkgs.sh b/ci-automation/push_pkgs.sh
index bb4c0e1b9a..4b0c153148 100644
--- a/ci-automation/push_pkgs.sh
+++ b/ci-automation/push_pkgs.sh
@@ -49,7 +49,15 @@ function image_build__copy_to_bincache() {
 
     source ci-automation/ci_automation_common.sh
 
+    # change the owner of the files and directories in __build__ back
+    # to ourselves, otherwise we could fail to sign the artifacts as
+    # we lacked write permissions in the directory of the signed
+    # artifact
+    local uid=$(id --user)
+    local gid=$(id --group)
     cd /build/$arch-usr/var/lib/portage/pkgs/
+    sudo chown --recursive "${uid}:${gid}" .
+    sign_artifacts "${SIGNER}" *
     copy_to_buildcache "boards/$arch-usr/$version/pkgs" *
 }
 # --
diff --git a/ci-automation/sdk_bootstrap.sh b/ci-automation/sdk_bootstrap.sh
index c09388cb7e..b35f4192ca 100644
--- a/ci-automation/sdk_bootstrap.sh
+++ b/ci-automation/sdk_bootstrap.sh
@@ -134,7 +134,15 @@ function _sdk_bootstrap_impl() {
     source sdk_container/.repo/manifests/version.txt
     local dest_tarball="flatcar-sdk-${ARCH}-${FLATCAR_SDK_VERSION}.tar.bz2"
 
+    # change the owner of the files and directories in __build__ back
+    # to ourselves, otherwise we could fail to sign the artifacts as
+    # we lacked write permissions in the directory of the signed
+    # artifact
+    local uid=$(id --user)
+    local gid=$(id --group)
+    sudo chown --recursive "${uid}:${gid}" __build__
     cd "__build__/images/catalyst/builds/flatcar-sdk"
+    sign_artifacts "${SIGNER}" "${dest_tarball}"*
     copy_to_buildcache "sdk/${ARCH}/${FLATCAR_SDK_VERSION}" "${dest_tarball}"*
     cd -
 }
diff --git a/ci-automation/vms.sh b/ci-automation/vms.sh
index cfcc6e3a95..ca69164485 100644
--- a/ci-automation/vms.sh
+++ b/ci-automation/vms.sh
@@ -117,6 +117,7 @@ function _vm_build_impl() {
         cp --reflink=auto -R "${CONTAINER_IMAGE_ROOT}/${arch}-usr/" "./${images_out}/"
 
     cd "images/latest"
+    sign_artifacts "${SIGNER}" *
     copy_to_buildcache "images/${arch}/${vernum}/" *
 }
 # --