diff --git a/helper.go b/helper.go
index f7590dc..f60e822 100644
--- a/helper.go
+++ b/helper.go
@@ -13,8 +13,8 @@ func BytesToString(b []byte) string {
 func StringToBytes(s string) (b []byte) {
 	bh := (*slice)(unsafe.Pointer(&b))
 	sh := (*slice)(unsafe.Pointer(&s))
-	bh.Data = sh.Data
-	bh.Len = sh.Len
-	bh.Cap = sh.Len
+	bh.data = sh.data
+	bh.len = sh.len
+	bh.cap = sh.len
 	return b
 }
diff --git a/slice.go b/slice.go
index b133217..cf66464 100644
--- a/slice.go
+++ b/slice.go
@@ -9,7 +9,7 @@ import "unsafe"
 // Unlike reflect.SliceHeader, its Data field is sufficient to guarantee the
 // data it references will not be garbage collected.
 type slice struct {
-	Data unsafe.Pointer
-	Len  int
-	Cap  int
+	data unsafe.Pointer
+	len  int
+	cap  int
 }