diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..f99da82
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.idea
+*.iml
+demo
diff --git a/BUILD.md b/BUILD.md
index bc8e13d..6fb01aa 100644
--- a/BUILD.md
+++ b/BUILD.md
@@ -10,7 +10,7 @@ Building CPABE
 ## Build
 
 1. Copy `jpbc-api-${version}.jar`,`jpbc-plaf-${version}`.jar to `cpabe-api/lib`
-   where version >= 1.2.1.
+   where version=1.2.1.
 2. Build the package `mvn package`.
 
 ## Demo