diff --git a/Src/Util/Format.cpp b/Src/Util/Format.cpp
index da16f74..df55349 100644
--- a/Src/Util/Format.cpp
+++ b/Src/Util/Format.cpp
@@ -41,7 +41,7 @@ namespace Util
 
   static const char hex_digits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
 
-  std::string Hex(uint32_t n, size_t num_digits)
+  std::string Hex(uint64_t n, size_t num_digits)
   {
     Util::Format f;
     f << "0x";
@@ -53,6 +53,11 @@ namespace Util
     return f;
   }
 
+  std::string Hex(uint64_t n)
+  {
+    return Hex(n, 16);
+  }
+
   std::string Hex(uint32_t n)
   {
     return Hex(n, 8);
diff --git a/Src/Util/Format.h b/Src/Util/Format.h
index 91aa308..e434205 100644
--- a/Src/Util/Format.h
+++ b/Src/Util/Format.h
@@ -95,7 +95,8 @@ namespace Util
   std::ostream &operator<<(std::ostream &os, const Format &format);
   std::string ToLower(const std::string &str);
   std::string TrimWhiteSpace(const std::string &str);
-  std::string Hex(uint32_t n, size_t num_digits);
+  std::string Hex(uint64_t n, size_t num_digits);
+  std::string Hex(uint64_t n);
   std::string Hex(uint32_t n);
   std::string Hex(uint16_t n);
   std::string Hex(uint8_t n);