diff --git a/impl.cpp b/impl.cpp
new file mode 100644
index 0000000..74a8969
--- /dev/null
+++ b/impl.cpp
@@ -0,0 +1,55 @@
+#include <exception>
+#include <iostream>
+#include <iterator>
+#include "impl.hpp"
+
+namespace openpower
+{
+namespace vpd
+{
+namespace parser
+{
+
+namespace offsets
+{
+
+enum Offsets
+{
+    VHDR = 17
+};
+
+}
+
+namespace lengths
+{
+
+enum Lengths
+{
+    RECORD_NAME = 4,
+    RECORD_MIN = 44,
+};
+
+}
+
+void Impl::checkHeader() const
+{
+    if (vpd.empty() || (lengths::RECORD_MIN > vpd.size()))
+    {
+        throw std::runtime_error("Malformed VPD");
+    }
+    else
+    {
+        auto iterator = vpd.cbegin();
+        std::advance(iterator, offsets::VHDR);
+        auto stop = std::next(iterator, lengths::RECORD_NAME);
+        std::string record(iterator, stop);
+        if ("VHDR" != record)
+        {
+            throw std::runtime_error("VHDR record not found");
+        }
+    }
+}
+
+} // namespace parser
+} // namespace vpd
+} // namespace openpower