diff --git a/include/libtorrent/aux_/escape_string.hpp b/include/libtorrent/aux_/escape_string.hpp
index 0b73d423a..009d6642f 100644
--- a/include/libtorrent/aux_/escape_string.hpp
+++ b/include/libtorrent/aux_/escape_string.hpp
@@ -37,21 +37,22 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/config.hpp"
 #include "libtorrent/error_code.hpp"
 #include "libtorrent/string_view.hpp"
+#include "libtorrent/flags.hpp"
 
 namespace libtorrent {
 
+	// hidden
+	struct encode_string_flags_tag;
+	using encode_string_flags_t = flags::bitfield_flag<std::uint8_t, encode_string_flags_tag>;
+
 	namespace string
 	{
-		enum flags_t
-		{
-			// use lower case alphabet used with i2p
-			lowercase = 0x1,
-			// don't insert padding
-			no_padding = 0x2,
-			// shortcut used for addresses as sha256 hashes
-			i2p = lowercase | no_padding
-		};
-
+		// use lower case alphabet used with i2p
+		constexpr encode_string_flags_t lowercase{0x1};
+		// don't insert padding
+		constexpr encode_string_flags_t no_padding{0x2};
+		// shortcut used for addresses as sha256 hashes
+		constexpr encode_string_flags_t i2p = lowercase | no_padding;
 	}
 
 	TORRENT_EXTRA_EXPORT std::string unescape_string(string_view s, error_code& ec);
@@ -80,7 +81,7 @@ namespace libtorrent {
 	TORRENT_EXTRA_EXPORT std::string base64encode(std::string const& s);
 #if TORRENT_USE_I2P
 	// encodes a string using the base32 scheme
-	TORRENT_EXTRA_EXPORT std::string base32encode(string_view s, int flags = 0);
+	TORRENT_EXTRA_EXPORT std::string base32encode(string_view s, encode_string_flags_t flags = {});
 #endif
 	TORRENT_EXTRA_EXPORT std::string base32decode(string_view s);
 
diff --git a/src/escape_string.cpp b/src/escape_string.cpp
index a096fd00a..663f6f1d2 100644
--- a/src/escape_string.cpp
+++ b/src/escape_string.cpp
@@ -340,7 +340,7 @@ namespace libtorrent {
 	}
 
 #if TORRENT_USE_I2P
-	std::string base32encode(string_view s, int flags)
+	std::string base32encode(string_view s, encode_string_flags_t const flags)
 	{
 		static char const base32_table_canonical[] =
 		{
@@ -356,7 +356,7 @@ namespace libtorrent {
 			'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
 			'y', 'z', '2', '3', '4', '5', '6', '7'
 		};
-		char const *base32_table = 0 != (flags & string::lowercase) ? base32_table_lowercase : base32_table_canonical;
+		char const *base32_table = (flags & string::lowercase) ? base32_table_lowercase : base32_table_canonical;
 
 		static aux::array<int, 6> const input_output_mapping{{{0, 2, 4, 5, 7, 8}}};
 
@@ -392,7 +392,7 @@ namespace libtorrent {
 				ret += base32_table[outbuf[j]];
 			}
 
-			if (0 == (flags & string::no_padding))
+			if (!(flags & string::no_padding))
 			{
 				// write pad
 				for (int j = 0; j < int(outbuf.size()) - num_out; ++j)