diff --git a/README.md b/README.md
index c63e13b..a151779 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ The idea was taken from https://gist.github.com/wikrie/f1d5747a714e0a34d0582981f
 
 ## Usage
 
-You have to provide a baseurl for your FRITZ!Box, a username, a password, and a certpath to contain `fullchain.pem` and `privkey.pem`. This can be done using environment variables or command line options. Command line options have a higher precedence.
+You have to provide a baseurl for your FRITZ!Box, a username, a password, and a certpath to contain `fullchain.pem` and `privkey.pem`. Optionally you can specify a key password. This can be done using environment variables or command line options. Command line options have a higher precedence.
 
 | Parameter | Environment         | Command line option |
 | --------- | ------------------- | ------------------- |
@@ -14,6 +14,7 @@ You have to provide a baseurl for your FRITZ!Box, a username, a password, and a
 | username  | `FRITZBOX_USERNAME` | `-u`                |
 | password  | `FRITZBOX_PASSWORD` | `-p`                |
 | certpath  | `FRITZBOX_CERTPATH` | `-c`                |
+| keypass   | `FRITZBOX_KEYPASS ` | `-k`                |
 | debug     | `FRITZBOX_DEBUG`    | `-d`                |
 
 For debugging set the environment variable `FRITZBOX_DEBUG` to any non-empty string or use the command line option `-d`. The HTTP requests and responses will be written to `/tmp/fritzbox.debug` then.
diff --git a/fritzbox_upload_certificate.sh b/fritzbox_upload_certificate.sh
index 7de3934..bf279bd 100755
--- a/fritzbox_upload_certificate.sh
+++ b/fritzbox_upload_certificate.sh
@@ -18,9 +18,10 @@
 # default parameters from environment
 baseurl="${FRITZBOX_BASEURL:-}"
 certpath="${FRITZBOX_CERTPATH:-}"
+debug="${FRITZBOX_DEBUG:-}"
+keypass="${FRITZBOX_KEYPASS:-}"
 password="${FRITZBOX_PASSWORD:-}"
 username="${FRITZBOX_USERNAME:-}"
-debug="${FRITZBOX_DEBUG:-}"
 
 CURL_CMD="curl"
 ICONV_CMD="iconv"
@@ -30,7 +31,7 @@ SUCCESS_MESSAGES="^ *(Das SSL-Zertifikat wurde erfolgreich importiert|Import of
 DEBUG_OUTPUT=/tmp/fritzbox.debug
 
 function usage {
-  echo "Usage: $0 [-b baseurl] [-u username] [-p password] [-c certpath]" >&2
+  echo "Usage: $0 [-b baseurl] [-u username] [-p password] [-c certpath] [-k keypass]" >&2
   exit 64
 }
 
@@ -65,7 +66,7 @@ done
 
 [ ${exit} -ne 0 ] && exit ${exit}
 
-while getopts ":b:c:dp:u:h" opt; do
+while getopts ":b:c:dk:p:u:h" opt; do
   case ${opt} in
     b)
       baseurl=$OPTARG
@@ -76,6 +77,9 @@ while getopts ":b:c:dp:u:h" opt; do
     d)
       debug="true"
       ;;
+    k)
+      keypass=$OPTARG
+      ;;
     p)
       password=$OPTARG
       ;;
@@ -181,6 +185,15 @@ ${certbundle}
 --${boundary}--
 EOD
 
+if [ -n "${keypass}" ]; then
+cat <<EOD >> "${request_file}"
+Content-Disposition: form-data; name="BoxCertPassword"
+
+${keypass}
+--${boundary}--
+EOD
+fi
+
 # upload the certificate to the box
 # shellcheck disable=SC2086
 ${CURL_CMD} ${curl_opts} -X POST "${baseurl}/cgi-bin/firmwarecfg" -H "Content-type: multipart/form-data boundary=${boundary}" --data-binary "@${request_file}" | process_curl_output | grep -qE "${SUCCESS_MESSAGES}"