diff --git a/Makefile.am b/Makefile.am
index cae800b..a7bcda7 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -34,7 +34,7 @@ guix-commit.txt: Makefile
 %.html: %.html.tmpl guix-commit.txt Makefile
 	sed 's#DOMAIN#$(DOMAIN)#g' $< > $@
 
-%.scm: %.scm.tmpl guix-commit.txt Makefile
+%.scm: %.scm.tmpl guix-commit.txt id_ed25519.pub Makefile signing-key.pub
 	sed \
 		"s#DOMAIN#$(DOMAIN)#g ; \
 		s#ENABLE_WIREGUARD#$(ENABLE_WIREGUARD)#g ; \
@@ -55,6 +55,19 @@ guix-commit.txt: Makefile
 		s#VM_SSH_ADDRESS#$(VM_SSH_ADDRESS)#g" $< > $@
 	chmod +x $@
 
+# Generate default key. Can be changed by replacing id_ed25519.pub.
+id_ed25519.pub:
+	printf "ssh-ed25519 %s %s" \
+	'AAAAC3NzaC1lZDI1NTE5AAAAIH2feuEj4asx0ImCG+cuiPv2WdKF6vMI+cJtZyG9cwUQ' \
+	'gnutoo@primary_laptop' \
+	> $@
+
+# Generate default key. Can be changed by replacing signing-key.pub.
+signing-key.pub:
+	printf '(public-key (ecc (curve Ed25519) (q #%s#)))\n' \
+	'3A7E1F41E2D5784CFCABB39CB73F99E727D4A5C1ECA79D873587D63D093CC4B5' \
+	>$@
+
 IMAGE_SOURCE = \
 	first-boot.sh \
 	guix-commit.txt \