diff --git a/protob/messages.proto b/protob/messages.proto
index f7b3f3765..decc934d7 100644
--- a/protob/messages.proto
+++ b/protob/messages.proto
@@ -406,6 +406,7 @@ message EncryptMessage {
 	optional bytes message = 2;				// message to encrypt
 	optional bool display_only = 3;				// show just on display? (don't send back via wire)
 	repeated uint32 address_n = 4;				// BIP-32 path to derive the signing key from master node
+	optional string coin_name = 5 [default='Bitcoin'];	// coin to use for signing
 }
 
 /**