diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6e8caaaf..289814e2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,7 +13,7 @@ This project uses the changelog in accordance with [keepchangelog](http://keepac
  - Fix the issue where some reader cause CU to enter a strange state (@xianglin1998)
  - The transmission performance of USB has been improved (@xianglin1998)
  - Added cmd for set mf1 config 'field_off_do_reset' (@xianglin1998)
-
+ - Fix Windows build (@suut)
 
 ## [v2.1.0][2025-09-02]
  - Added UV, formatter and linter. Contribution guidelines. (@GameTec-live)
diff --git a/software/src/CMakeLists.txt b/software/src/CMakeLists.txt
index f33c8d6c..d1372518 100644
--- a/software/src/CMakeLists.txt
+++ b/software/src/CMakeLists.txt
@@ -221,16 +221,18 @@ endif()
 add_executable(mfulc_des_brute mfulc_des_brute.c)
 target_include_directories(mfulc_des_brute PRIVATE ${SRC_DIR})
 target_link_libraries(mfulc_des_brute PRIVATE ${LIBTHREAD} OpenSSL::Crypto)
-target_compile_options(mfulc_des_brute PRIVATE -Wno-deprecated-declarations)
+if (MSVC)
+    target_compile_options(mfulc_des_brute PRIVATE /wd4996)  # disable "deprecated declaration" warning
+else()
+    target_compile_options(mfulc_des_brute PRIVATE -Wno-deprecated-declarations)
+endif()
 if (CMAKE_SYSTEM_NAME MATCHES "Linux" OR CMAKE_SYSTEM_NAME MATCHES "Android" OR CMAKE_SYSTEM_NAME MATCHES "Darwin")
     target_compile_definitions(mfulc_des_brute PRIVATE _GNU_SOURCE)
-    find_package(OpenSSL REQUIRED)
 endif()
 if (CMAKE_SYSTEM_NAME MATCHES "Windows")
     target_compile_definitions(mfulc_des_brute PRIVATE HAVE_STRUCT_TIMESPEC)
-    find_package(OpenSSL REQUIRED)
 endif()
-
+find_package(OpenSSL REQUIRED)
 
 # --- hardnested Executable ---
 add_executable(hardnested ${COMMON_FILES} ${HARDNESTED_SOURCES})
diff --git a/software/src/mfulc_des_brute.c b/software/src/mfulc_des_brute.c
index 7d7b3076..1357c106 100644
--- a/software/src/mfulc_des_brute.c
+++ b/software/src/mfulc_des_brute.c
@@ -10,6 +10,12 @@
 #include <pthread.h>
 #include <openssl/des.h>
 
+#ifdef _MSC_VER
+# define bswap64 _byteswap_uint64
+#else
+# define bswap64 __builtin_bswap64
+#endif
+
 #define BLOCK_SIZE 8   // DES (and 3DES) block size in bytes
 #define KEY_SIZE   16  // Full 2TDEA key size (K1 || K2)
 #define BENCHMARK_FULL_KEYSPACE 0
@@ -57,7 +63,7 @@ static void print_hex(const unsigned char *buf, size_t len) {
 }
 
 static bool valid_lfsr_ulcg(uint64_t x64) {
-    x64 = __builtin_bswap64(x64);
+    x64 = bswap64(x64);
     uint16_t x16 = x64 >> 48;
     x16 = x16 << 15 | ((x16 >> 1) ^ ((x16 >> 3 ^ x16 >> 4 ^ x16 >> 6) & 1));
     if (x16 != ((x64 >> 32) & 0xFFFF)) return false;
@@ -69,7 +75,7 @@ static bool valid_lfsr_ulcg(uint64_t x64) {
 }
 
 static bool valid_lfsr_uscuidul(uint64_t x64) {
-    x64 = __builtin_bswap64(x64);
+    x64 = bswap64(x64);
     uint16_t x16 = x64 & 0xFFFF;
     for (int i = 0; i < 16; i++) x16 = x16 >> 1 | (x16 ^ x16 >> 2 ^ x16 >> 3 ^ x16 >> 5) << 15;
     if (x16 != ((x64 >> 16) & 0xFFFF)) return false;
@@ -193,9 +199,9 @@ static void *worker(void *arg) {
 
             // Check if out is 8-bit (1-byte) left rotated version of init_out
             // Need to convert to big-endian for byte rotation, then back to little-endian
-            uint64_t init_be = __builtin_bswap64(init_out);
+            uint64_t init_be = bswap64(init_out);
             uint64_t rotated_be = (init_be << 8) | (init_be >> 56);
-            uint64_t rotated = __builtin_bswap64(rotated_be);
+            uint64_t rotated = bswap64(rotated_be);
             match = (out == rotated);
         } else {
             // In counterfeit mode, check the resulting plaintext against LFSR