diff --git a/model/PrivateVolume.h b/model/PrivateVolume.h
index cb8e75d..819632b 100644
--- a/model/PrivateVolume.h
+++ b/model/PrivateVolume.h
@@ -37,7 +37,7 @@
  */
 class PrivateVolume : public VolumeBase {
   public:
-    PrivateVolume(dev_t device, const std::string& keyRaw);
+    PrivateVolume(dev_t device, const KeyBuffer& keyRaw);
     virtual ~PrivateVolume();
     const std::string& getFsType() const { return mFsType; };
     const std::string& getRawDevPath() const { return mRawDevPath; };
@@ -63,7 +63,7 @@
     std::string mPath;
 
     /* Encryption key as raw bytes */
-    std::string mKeyRaw;
+    KeyBuffer mKeyRaw;
 
     /* Filesystem type */
     std::string mFsType;