diff --git a/fs_mgr/libfs_avb/avb_util.cpp b/fs_mgr/libfs_avb/avb_util.cpp
index 7d89902..f4e4d4e 100644
--- a/fs_mgr/libfs_avb/avb_util.cpp
+++ b/fs_mgr/libfs_avb/avb_util.cpp
@@ -326,7 +326,7 @@
     return false;
 }
 
-bool ValidatePublicKeyBlob(const std::string key_blob_to_validate,
+bool ValidatePublicKeyBlob(const std::string& key_blob_to_validate,
                            const std::vector<std::string>& allowed_key_paths) {
     std::string allowed_key_blob;
     if (key_blob_to_validate.empty()) {
diff --git a/fs_mgr/libfs_avb/avb_util.h b/fs_mgr/libfs_avb/avb_util.h
index 986a69a..09c786a 100644
--- a/fs_mgr/libfs_avb/avb_util.h
+++ b/fs_mgr/libfs_avb/avb_util.h
@@ -80,7 +80,7 @@
 
 bool ValidatePublicKeyBlob(const uint8_t* key, size_t length, const std::string& expected_key_blob);
 
-bool ValidatePublicKeyBlob(const std::string key_blob_to_validate,
+bool ValidatePublicKeyBlob(const std::string& key_blob_to_validate,
                            const std::vector<std::string>& expected_key_paths);
 
 // Detects if whether a partition contains a rollback image.