2 files changed, 31 insertions, 0 deletions
diff --git a/src/serialization/json_object.cpp b/src/serialization/json_object.cpp
index 6228b4bec..1f71126c3 100644
--- a/src/serialization/json_object.cpp
+++ b/src/serialization/json_object.cpp
@@ -146,6 +146,26 @@ void fromJsonValue(const rapidjson::Value& val, std::string& str)
   str = val.GetString();
 }
 
+void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const std::vector<std::uint8_t>& src)
+{
+  const std::string hex = epee::to_hex::string(epee::to_span(src));
+  dest.String(hex.data(), hex.size());
+}
+
+void fromJsonValue(const rapidjson::Value& val, std::vector<std::uint8_t>& dest)
+{
+  if (!val.IsString())
+  {
+    throw WRONG_TYPE("string");
+  }
+
+  dest.resize(val.GetStringLength() / 2);
+  if ((val.GetStringLength() % 2) != 0 || !epee::from_hex::to_buffer(epee::to_mut_span(dest), {val.GetString(), val.GetStringLength()}))
+  {
+    throw BAD_INPUT();
+  }
+}
+
 void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, bool i)
 {
   dest.Bool(i);
diff --git a/src/serialization/json_object.h b/src/serialization/json_object.h
index 2a9b63b08..9f652a679 100644
--- a/src/serialization/json_object.h
+++ b/src/serialization/json_object.h
@@ -153,6 +153,9 @@ inline void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const std::s
 }
 void fromJsonValue(const rapidjson::Value& val, std::string& str);
 
+void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const std::vector<std::uint8_t>&);
+void fromJsonValue(const rapidjson::Value& src, std::vector<std::uint8_t>& i);
+
 void toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, bool i);
 void fromJsonValue(const rapidjson::Value& val, bool& b);
 
@@ -353,6 +356,10 @@ inline typename std::enable_if<sfinae::is_map_like<Map>::value, void>::type from
 template <typename Vec>
 inline typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type toJsonValue(rapidjson::Writer<epee::byte_stream>& dest, const Vec &vec)
 {
+  using value_type = typename Vec::value_type;
+  static_assert(!std::is_same<value_type, char>::value, "encoding an array of chars is faster as hex");
+  static_assert(!std::is_same<value_type, unsigned char>::value, "encoding an array of unsigned char is faster as hex");
+
   dest.StartArray();
   for (const auto& t : vec)
     toJsonValue(dest, t);
@@ -362,6 +369,10 @@ inline typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type t
 template <typename Vec>
 inline typename std::enable_if<sfinae::is_vector_like<Vec>::value, void>::type fromJsonValue(const rapidjson::Value& val, Vec& vec)
 {
+  using value_type = typename Vec::value_type;
+  static_assert(!std::is_same<value_type, char>::value, "encoding a vector of chars is faster as hex");
+  static_assert(!std::is_same<value_type, unsigned char>::value, "encoding a vector of unsigned char is faster as hex");
+
   if (!val.IsArray())
   {
     throw WRONG_TYPE("json array");