diff --git a/Dockerfile b/Dockerfile
index 86d0eee..c22a1c2 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,9 +1,9 @@
-
 FROM fedora as builder
 MAINTAINER "Joe Doss" <joe@solidadmin.com>
 
 ARG WIREGUARD_VERSION
 ARG WIREGUARD_KERNEL_VERSION
+ARG WIREGUARD_SHA256
 
 WORKDIR /tmp
 
@@ -20,11 +20,13 @@ RUN dnf update -y && dnf install \
         kernel-devel-${WIREGUARD_KERNEL_VERSION}.rpm \
         kernel-modules-${WIREGUARD_KERNEL_VERSION}.rpm -y && \
         dnf clean all && \
-        curl -SL  https://git.zx2c4.com/WireGuard/snapshot/WireGuard-${WIREGUARD_VERSION}.tar.xz | tar xJ -C /usr/src/
+        curl -LS https://git.zx2c4.com/WireGuard/snapshot/WireGuard-${WIREGUARD_VERSION}.tar.xz | \
+        { t="$(mktemp)"; trap "rm -f '$t'" INT TERM EXIT; cat >| "$t"; sha256sum --quiet -c <<<"${WIREGUARD_SHA256} $t" \
+        || exit 1; cat "$t"; } | tar xJf -
 
-WORKDIR /usr/src/WireGuard-${WIREGUARD_VERSION}/src
+WORKDIR /tmp/WireGuard-${WIREGUARD_VERSION}/src
 
-RUN KERNELDIR=/usr/lib/modules/${WIREGUARD_KERNEL_VERSION}/build make && make install
+RUN KERNELDIR=/usr/lib/modules/${WIREGUARD_KERNEL_VERSION}/build make -j$(nproc) && make install
 
 FROM fedora
 MAINTAINER "Joe Doss" <joe@solidadmin.com>
@@ -35,10 +37,8 @@ WORKDIR /tmp
 
 RUN dnf update -y && dnf install kmod koji -y && \
         koji download-build --rpm --arch=x86_64 kernel-core-${WIREGUARD_KERNEL_VERSION} && \
-        koji download-build --rpm --arch=x86_64 kernel-devel-${WIREGUARD_KERNEL_VERSION} && \
         koji download-build --rpm --arch=x86_64 kernel-modules-${WIREGUARD_KERNEL_VERSION} && \
         dnf install /tmp/kernel-core-${WIREGUARD_KERNEL_VERSION}.rpm \
-        kernel-devel-${WIREGUARD_KERNEL_VERSION}.rpm \
         kernel-modules-${WIREGUARD_KERNEL_VERSION}.rpm -y && \
         dnf clean all && rm -f /tmp/*.rpm
 
diff --git a/README.md b/README.md
index ec83453..778faa5 100644
--- a/README.md
+++ b/README.md
@@ -59,7 +59,7 @@ unload      Unload wireguard kernel module
 reload      Build and reload wireguard kernel module
 ```
 
-Atomic Wireguard also has a systemd unit file which on start waits for NetworkManager to finish starting up and then it will build and load the WireGuard kernel module. You can also use `systemctl reload atomic-wireguard` to run the build process, unload and then load the kernel module. This is handy if you want to change the WireGuard kernel module version. To change the version, just edit the `WIREGUARD_VERSION` line in `/etc/sysconfig/atomic-wireguard`. Please note that this needs to be the exact version number of a released snapshot. You can verify that the kernel module is loaded with `lsmod |grep wireguard`.
+Atomic Wireguard also has a systemd unit file which on start waits for NetworkManager to finish starting up and then it will build and load the WireGuard kernel module. You can also use `systemctl reload atomic-wireguard` to run the build process, unload and then load the kernel module. This is handy if you want to change the WireGuard kernel module version. To change the version, just edit the `WIREGUARD_VERSION` and `WIREGUARD_SHA265` lines in `/etc/sysconfig/atomic-wireguard`. Please note that this needs to be the exact version number and SHA256 hash of a released WireGuard snapshot. You can verify that the kernel module is loaded with `lsmod |grep wireguard`.
 
 ### Setting up systemd-networkd
 
diff --git a/atomic-wireguard b/atomic-wireguard
index d637f09..15c9b2b 100644
--- a/atomic-wireguard
+++ b/atomic-wireguard
@@ -1,2 +1,3 @@
 WIREGUARD_PRUNE_OLD_VERSIONS=false
-WIREGUARD_VERSION=0.0.20180524
+WIREGUARD_SHA256=ff653095cc0e4c491ab6cd095ddf5d1db207f48f947fb92873a73220363f423c
+WIREGUARD_VERSION=0.0.20180531
diff --git a/atomic-wireguard-module b/atomic-wireguard-module
index 6c5e7c8..f4af0f9 100755
--- a/atomic-wireguard-module
+++ b/atomic-wireguard-module
@@ -38,7 +38,9 @@ build_wireguard()
     echo "The WireGuard ${WIREGUARD_VERSION} kernel module container is not built."
     echo "Building ${WIREGUARD_VERSION} kernel module for ${WIREGUARD_KERNEL_VERSION} ..."
 
-    podman build --build-arg WIREGUARD_VERSION=${WIREGUARD_VERSION} --build-arg WIREGUARD_KERNEL_VERSION=${WIREGUARD_KERNEL_VERSION} \
+    podman build --build-arg WIREGUARD_VERSION=${WIREGUARD_VERSION} \
+    --build-arg WIREGUARD_SHA256=${WIREGUARD_SHA256} \
+    --build-arg WIREGUARD_KERNEL_VERSION=${WIREGUARD_KERNEL_VERSION} \
     -t wireguard:${WIREGUARD_VERSION} git://github.com/jdoss/atomic-wireguard
   fi
 
@@ -50,7 +52,9 @@ build_wireguard()
     echo "The WireGuard kernel module for ${WIREGUARD_KERNEL_VERSION} is not the correct version."
     echo "Building ${WIREGUARD_VERSION} kernel module for ${WIREGUARD_KERNEL_VERSION} ..."
 
-    podman build --build-arg WIREGUARD_VERSION=${WIREGUARD_VERSION} --build-arg WIREGUARD_KERNEL_VERSION=${WIREGUARD_KERNEL_VERSION} \
+    podman build --build-arg WIREGUARD_VERSION=${WIREGUARD_VERSION} \
+    --build-arg WIREGUARD_SHA256=${WIREGUARD_SHA256} \
+    --build-arg WIREGUARD_KERNEL_VERSION=${WIREGUARD_KERNEL_VERSION} \
     -t wireguard:${WIREGUARD_VERSION} git://github.com/jdoss/atomic-wireguard
   fi