diff --git a/dub.json b/dub.json
index c7acef5259..9753baf7cf 100644
--- a/dub.json
+++ b/dub.json
@@ -13,7 +13,11 @@
 
 	"systemDependencies": "libevent 2.0.x or libev, OpenSSL 0.9.x or 1.0.x",
 	"dependencies": {
-		"openssl": ">=1.0.0+1.0.0e"
+		"openssl": ">=1.0.0+1.0.0e",
+		"botan": {
+			"version": "~>1.12.0",
+			"optional": true
+		}
 	},
 
 	"targetType": "library",