diff --git a/Dockerfile b/Dockerfile
index 479e708..69fd86c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,7 +8,7 @@ RUN apt-get -y update && \
         git vim parted \
         quilt coreutils qemu-user-static debootstrap zerofree zip dosfstools \
         libarchive-tools libcap2-bin rsync grep udev xz-utils curl xxd file kmod bc\
-        binfmt-support ca-certificates qemu-utils kpartx fdisk \
+        binfmt-support ca-certificates qemu-utils kpartx fdisk gpg \
     && rm -rf /var/lib/apt/lists/*
 
 COPY . /pi-gen/
diff --git a/README.md b/README.md
index 893a5cc..cda0255 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ To install the required dependencies for `pi-gen` you should run:
 ```bash
 apt-get install coreutils quilt parted qemu-user-static debootstrap zerofree zip \
 dosfstools libarchive-tools libcap2-bin grep rsync xz-utils file git curl bc \
-qemu-utils kpartx
+qemu-utils kpartx gpg
 ```
 
 The file `depends` contains a list of tools needed.  The format of this
diff --git a/depends b/depends
index eeb2490..654531a 100644
--- a/depends
+++ b/depends
@@ -19,3 +19,4 @@ lsmod:kmod
 bc
 qemu-nbd:qemu-utils
 kpartx
+gpg