diff --git a/Dockerfile b/Dockerfile
index 000b4fb..b6d7c82 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,6 +3,14 @@ FROM gcr.io/gcp-runtimes/go1-builder:1.13 as builder
 
 ENV PATH "/usr/local/go/bin:$PATH"
 
+# Inject custom root certificate authorities if needed.
+# Docker does not have a good conditional copy statement and requires that a
+# source file exists to complete the copy function without error. Therefore, the
+# README.md file will be copied to the image every time even if there are no
+# .crt files.
+COPY ./certs/* /usr/local/share/ca-certificates/
+RUN update-ca-certificates
+
 WORKDIR /workspace
 # Copy the Go Modules manifests
 COPY go.mod go.mod
diff --git a/certs/README.md b/certs/README.md
new file mode 100644
index 0000000..2a07450
--- /dev/null
+++ b/certs/README.md
@@ -0,0 +1,8 @@
+# Additional Docker image root certificate authorities
+
+If you require additional certificate authorities for your Docker image:
+* Add ASCII PEM encoded .crt files to this directory
+  * The files will be copied into your docker image at build time.
+
+To update manually copy the `.crt` files to `/usr/local/share/ca-certificates/`
+and run `sudo update-ca-certificates`.