strencodings:add ChallengeToStdString

Author: RandyMcMillan

src/util/strencodings.cpp

@@ -383,6 +383,25 @@ std::string Capitalize(std::string str)
     return str;
 }
 
+std::string ChallengeToStdString(const std::vector<uint8_t>& v)
+{
+    std::string result;
+    result.reserve(v.size() * 2);
+
+    static constexpr char hex[] = "0123456789ABCDEF";
+
+    for (uint8_t c : v)
+    {
+        result.push_back(hex[c / 16]);
+        result.push_back(hex[c % 16]);
+    }
+    if (IsHex(result)) {
+        return result;
+    } else {
+        return "Invalid signet_challenge";
+        }
+    }
+
 std::optional<uint64_t> ParseByteUnits(std::string_view str, ByteUnit default_multiplier)
 {
     if (str.empty()) {

src/util/strencodings.h

@@ -311,6 +311,11 @@ std::string ToUpper(std::string_view str);
  */
 std::string Capitalize(std::string str);
 
+/**
+ * Converts a signet_challenge to std::string
+ */
+std::string ChallengeToStdString(const std::vector<uint8_t>& v);
+
 /**
  * Parse a string with suffix unit [k|K|m|M|g|G|t|T].
  * Must be a whole integer, fractions not allowed (0.5t), no whitespace or +-