diff --git a/resources/com/cadoles/common/add-letsencrypt-ca.sh b/resources/com/cadoles/common/add-letsencrypt-ca.sh
new file mode 100644
index 0000000..c0c0937
--- /dev/null
+++ b/resources/com/cadoles/common/add-letsencrypt-ca.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+set -eo pipefail
+
+DESTDIR=/usr/local/share/ca-certificates
+UPDATE_CERTS_CMD=update-ca-certificates
+CERTS="$(cat <<EOF
+https://letsencrypt.org/certs/isrgrootx1.pem
+https://letsencrypt.org/certs/isrg-root-x2.pem
+https://letsencrypt.org/certs/lets-encrypt-r3.pem
+https://letsencrypt.org/certs/lets-encrypt-e1.pem
+https://letsencrypt.org/certs/lets-encrypt-r4.pem
+https://letsencrypt.org/certs/lets-encrypt-e2.pem
+EOF
+)"
+
+cd "$DESTDIR"
+
+for cert in $CERTS; do
+    echo "Downloading '$cert'..."
+    filename=$(basename "$cert")
+    wget -O "$filename" "$cert"
+    openssl x509 -in "$filename" -inform PEM -out "$filename.crt"
+done
+
+$UPDATE_CERTS_CMD
\ No newline at end of file
diff --git a/resources/com/cadoles/tamarin/Dockerfile b/resources/com/cadoles/tamarin/Dockerfile
index 5a36a00..ef78181 100644
--- a/resources/com/cadoles/tamarin/Dockerfile
+++ b/resources/com/cadoles/tamarin/Dockerfile
@@ -9,18 +9,8 @@ ARG TAMARIN_VERSION=develop
 
 RUN apk add --no-cache git docker python3 bash openssl
 
-ADD https://letsencrypt.org/certs/isrgrootx1.pem.txt /usr/local/share/ca-certificates/isrgrootx1.pem
-ADD https://letsencrypt.org/certs/isrg-root-x2.pem  /usr/local/share/ca-certificates/isrg-root-x2.pem
-ADD https://letsencrypt.org/certs/trustid-x3-root.pem.txt /usr/local/share/ca-certificates/trustid-x3-root.pem
-ADD https://letsencrypt.org/certs/letsencryptauthorityx3.pem /usr/local/share/ca-certificates/letsencryptauthorityx3.pem 
-
-RUN cd /usr/local/share/ca-certificates \
- && openssl x509 -in isrgrootx1.pem -inform PEM -out isrgrootx1.crt \
- && openssl x509 -in trustid-x3-root.pem -inform PEM -out trustid-x3-root.crt \
- && openssl x509 -in letsencryptauthorityx3.pem -inform PEM -out letsencryptauthorityx3.crt \
- && openssl x509 -in isrg-root-x2.pem -inform PEM -out isrg-root-x2.crt
-
-RUN update-ca-certificates  
+COPY add-letsencrypt-ca.sh /usr/local/bin/add-letsencrypt-ca
+RUN chmod +x /usr/local/bin/add-letsencrypt-ca && /usr/local/bin/add-letsencrypt-ca
 
 RUN git clone http://forge.cadoles.com/Cadoles/Tamarin /tamarin\
   && cd /tamarin\
diff --git a/vars/tamarin.groovy b/vars/tamarin.groovy
index 55f3b1e..b2d66c9 100644
--- a/vars/tamarin.groovy
+++ b/vars/tamarin.groovy
@@ -121,6 +121,9 @@ def buildDockerImage() {
 
         def runTamarinScript = libraryResource 'com/cadoles/tamarin/run-tamarin.sh'
         writeFile file:'run-tamarin.sh', text:runTamarinScript
+
+        def addLetsEncryptCA = libraryResource 'com/cadoles/common/add-letsencrypt-ca.sh'
+        writeFile file:'add-letsencrypt-ca.sh', text:addLetsEncryptCA
         
         def safeJobName = URLDecoder.decode(env.JOB_NAME).toLowerCase().replace('/', '-').replace(' ', '-')
         def imageTag = "${safeJobName}-${env.BUILD_ID}"