diff --git a/luprex/core/Makefile b/luprex/core/Makefile
index cc9f1b52..dd6c6036 100644
--- a/luprex/core/Makefile
+++ b/luprex/core/Makefile
@@ -73,8 +73,8 @@ CORE_OBJ_FILES=\
 
 
 DRV_OBJ_FILES=\
-	objdrv/drvutil.o\
-	objdrv/sslutil.o\
+	obj/drv/drvutil.o\
+	obj/drv/sslutil.o\
 
 
 -include $(LUA_OBJ_FILES:%.o=%.d)
@@ -86,8 +86,8 @@ ifeq ($(OS),linux)
 
 OPT=-g -O0
 
-main:  $(DRV_OBJ_FILES) $(CORE_OBJ_FILES)  $(LUA_OBJ_FILES) objdrv/driver-linux.o
-	g++ -std=c++17 -export-dynamic -Wall $(OPT) -o $@ $(DRV_OBJ_FILES) $(CORE_OBJ_FILES) $(LUA_OBJ_FILES) objdrv/driver-linux.o -L../linuxlib -lssl -lcrypto -ldl
+main:  $(DRV_OBJ_FILES) $(CORE_OBJ_FILES)  $(LUA_OBJ_FILES) obj/drv/driver-linux.o
+	g++ -std=c++17 -export-dynamic -Wall $(OPT) -o $@ $(DRV_OBJ_FILES) $(CORE_OBJ_FILES) $(LUA_OBJ_FILES) obj/drv/driver-linux.o -L../linuxlib -lssl -lcrypto -ldl
 
 obj/lua/%.o: ../eris-master/src/%.c
 	gcc -Wall -fvisibility=hidden $(OPT) -DLUA_USE_APICHECK -DLUA_USE_POSIX -c -MMD $< -o $@
@@ -95,13 +95,13 @@ obj/lua/%.o: ../eris-master/src/%.c
 obj/cpp/%.o: cpp/%.cpp
 	g++ -Wall -fvisibility=hidden $(OPT) -std=c++17 -I../linuxlib -I../eris-master/src -Iwrap -Icpp -c -MMD $< -o $@
 
-objdrv/%.o: drv/%.cpp
+obj/drv/%.o: drv/%.cpp
 	g++ -Wall -fvisibility=hidden $(OPT) -std=c++17 -I../linuxlib -Idrv -c -MMD $< -o $@
 
 endif
 
 clean:
-	rm -f main.exe main obj/cpp/*.* objdrv/*.* obj/lua/*.*
+	rm -f main.exe main obj/cpp/*.* obj/drv/*.* obj/lua/*.*
 
 
 
diff --git a/luprex/core/drv/driver-linux.cpp b/luprex/core/drv/driver-linux.cpp
index 2dc4e384..a7bc4584 100644
--- a/luprex/core/drv/driver-linux.cpp
+++ b/luprex/core/drv/driver-linux.cpp
@@ -32,6 +32,7 @@ const int INVALID_SOCKET = -1;
 
 struct termios orig_termios;
 
+
 void set_nonblocking(int fd) {
     int flags = fcntl(fd, F_GETFL, 0);
     assert(flags != -1);
diff --git a/luprex/core/drv/driver-mingw.cpp b/luprex/core/drv/driver-mingw.cpp
index 0741e8fc..b539eb3b 100644
--- a/luprex/core/drv/driver-mingw.cpp
+++ b/luprex/core/drv/driver-mingw.cpp
@@ -9,6 +9,7 @@
 #include <cstdio>
 #include <cstring>
 #include <cassert>
+#include <filesystem>
 
 #include <winsock2.h>
 #include <ws2tcpip.h>
@@ -23,6 +24,20 @@
 #include <openssl/bio.h>
 #include <openssl/pem.h>
 
+// OpenSSL requires plain ascii pathnames.  Returns empty string
+// if the path cannot be converted to plain ascii.
+std::string path_to_plain_ascii(const std::filesystem::path &path) {
+	std::wstring s = path.native();
+	for (wchar_t c : s) {
+		if ((c < 1) || (c > 127)) return "";
+	}
+	std::ostringstream oss;
+	for (wchar_t c : s) {
+		oss << ((char)c);
+	}
+	return oss.str();
+}
+	
 static void set_nonblocking(SOCKET sock) {
     u_long mode = 1;  // 1 to enable non-blocking socket
     int status = ioctlsocket(sock, FIONBIO, &mode);
diff --git a/luprex/core/drv/sslutil.cpp b/luprex/core/drv/sslutil.cpp
index 33878c86..a60a5ca4 100644
--- a/luprex/core/drv/sslutil.cpp
+++ b/luprex/core/drv/sslutil.cpp
@@ -87,6 +87,14 @@ std::string error_string() {
     }
 }
 
+std::string path_to_plain_ascii(const std::filesystem::path &path) {
+	std::string s = path.native();
+	for (char c : s) {
+		if ((c < 1) || (c > 127)) return "";
+	}
+	return s;
+}
+
 void clear_all_errors() {
     ERR_clear_error();
     errno = 0;
@@ -162,13 +170,17 @@ void ctx_load_cert_from_directory(SSL_CTX *ctx, const std::string &dir) {
     std::vector<std::string> cert_paths;
 
     for (const auto & entry : std::filesystem::directory_iterator(dir)) {
-        std::string fn = entry.path();
-        if (count_certificates(fn.c_str()) >= 1) {
-            cert_paths.push_back(fn);
-        }
-        if (contains_privatekey(fn.c_str())) {
-            key_paths.push_back(fn);
-        }
+		std::string fn = path_to_plain_ascii(entry.path());
+		if (fn.empty()) {
+			std::cerr << "Ignoring file with non-ascii filename: " << entry.path() << std::endl;
+		} else {
+			if (count_certificates(fn.c_str()) >= 1) {
+				cert_paths.push_back(fn);
+			}
+			if (contains_privatekey(fn.c_str())) {
+				key_paths.push_back(fn);
+			}
+		}
     }
 
     if (cert_paths.size() > 1) {