diff --git a/builder/Dockerfile b/builder/Dockerfile
index 89bcbc4..6568fee 100644
--- a/builder/Dockerfile
+++ b/builder/Dockerfile
@@ -2,6 +2,8 @@ FROM docker
 
 RUN apk add --no-cache \
 		ca-certificates \
+		coreutils \
+		gnupg \
 		libffi \
 		mktorrent \
 		openssh-client \
@@ -22,10 +24,24 @@ RUN apk add --no-cache \
 
 ARG PACKER_VERSION
 
-RUN mkdir -p /usr/local/bin \
-	&& wget -O /tmp/packer.zip -c https://releases.hashicorp.com/packer/${PACKER_VERSION}/packer_${PACKER_VERSION}_linux_amd64.zip \
-	&& unzip /tmp/packer.zip -d /usr/local/bin \
-	&& rm -f /tmp/packer.zip \
+COPY hashicorp.asc /usr/local/share/
+
+RUN gpg --import /usr/local/share/hashicorp.asc \
+	&& mkdir -p \
+		/usr/local/bin \
+		/tmp/packer \
+	&& (cd /tmp/packer \
+		&& wget --no-verbose \
+			https://releases.hashicorp.com/packer/${PACKER_VERSION}/packer_${PACKER_VERSION}_linux_amd64.zip \
+			https://releases.hashicorp.com/packer/${PACKER_VERSION}/packer_${PACKER_VERSION}_SHA256SUMS \
+			https://releases.hashicorp.com/packer/${PACKER_VERSION}/packer_${PACKER_VERSION}_SHA256SUMS.sig \
+		&& gpg --verify \
+			packer_${PACKER_VERSION}_SHA256SUMS.sig \
+			packer_${PACKER_VERSION}_SHA256SUMS \
+		&& sha256sum -c --strict --ignore-missing packer_${PACKER_VERSION}_SHA256SUMS | grep -F "packer_${PACKER_VERSION}_linux_amd64.zip: OK" \
+		&& unzip *.zip -d /usr/local/bin \
+		&& rm -f /tmp/packer.zip \
+	) \
 	&& mkdir /workdir
 
 WORKDIR /workdir
@@ -33,3 +49,4 @@ WORKDIR /workdir
 COPY entrypoint.sh /usr/local/bin/entrypoint.sh
 
 ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]
+# vim: ts=4 sw=4 sts=4 noet:
diff --git a/builder/hashicorp.asc b/builder/hashicorp.asc
new file mode 100644
index 0000000..010c927
--- /dev/null
+++ b/builder/hashicorp.asc
@@ -0,0 +1,30 @@
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+Version: GnuPG v1
+
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+=LYpS
+-----END PGP PUBLIC KEY BLOCK-----