diff --git a/src/hex.cpp b/src/hex.cpp
index 3e94368..9ce8feb 100644
--- a/src/hex.cpp
+++ b/src/hex.cpp
@@ -1,3 +1,4 @@
+#include <span>
 #include <stdexcept>
 
 #include <base/baseN.hpp>
@@ -37,14 +38,12 @@ namespace hex
     void encode(const uint8_t *data, uint64_t data_size, char *str) noexcept
     {
         std::string_view sv(str);
-        for(size_t i = 0; i < sv.size() && i / 2 < data_size; i++)
+        std::span<const uint8_t> dv(data, data_size);
+
+        for (size_t i = 0; i < dv.size() && i * 2 + 1 < sv.size(); i++)
         {
-            if (i % 2 == 0)
-            {
-                str[i] = hexdigits[data[i / 2] >> 4];
-            } else {
-                str[i] = hexdigits[data[i / 2] & 0x0F];
-            }
+            str[i * 2] = hexdigits[dv[i] >> 4];
+            str[i * 2 + 1] = hexdigits[dv[i] & 0x0F];
         }
     }
     std::string encode(const std::vector<uint8_t> &data) noexcept
@@ -60,13 +59,15 @@ namespace hex
             throw std::logic_error("hex::decode: out of digits map");
         }
         std::string_view sv(str);
+        std::span<const uint8_t> dv(data, data_size);
         if (sv.size() % 2 != 0)
         {
             throw std::logic_error("hex::decode: isn't hex");
         }
-        for (size_t i = 0; i < data_size && i * 2 < sv.size(); i++)
+
+        for (size_t i = 0; i < dv.size() && i * 2 < sv.size(); i++)
         {
-            data[i] = hexmap[(int8_t)str[i * 2]] << 4 | hexmap[(int8_t)str[i * 2 + 1]];
+            data[i] = hexmap[(int8_t)sv[i * 2]] << 4 | hexmap[(int8_t)sv[i * 2 + 1]];
         }
     }
     std::vector<uint8_t> decode(const std::string &str)