diff --git a/.env.sample b/.env.sample
index c8c7521..bc2a4b0 100644
--- a/.env.sample
+++ b/.env.sample
@@ -5,7 +5,7 @@ DOMAIN=garage.example.com
 LETS_ENCRYPT_ENV=production
 COMPOSE_FILE="compose.yml"
 
-SECRET_RPC_SECRET_VERSION=v1
+SECRET_RPC_SECRET_VERSION=v1 # length=32 charset=hex
 
  # Changing the replication factor after initial deployment is not 
  # supported and requires deleting the existing cluster layout metadata.