diff --git a/src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c b/src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c
index b5c8e889..cf617360 100644
--- a/src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c
+++ b/src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c
@@ -20,8 +20,8 @@
 #include "utils.h"
 
 #ifdef _WIN32
-# include <Windows.h>
-# include <Wincrypt.h>
+# include <windows.h>
+# include <wincrypt.h>
 # include <sys/timeb.h>
 #endif
 
diff --git a/src/libsodium/randombytes/sysrandom/randombytes_sysrandom.c b/src/libsodium/randombytes/sysrandom/randombytes_sysrandom.c
index 84a1c857..eec5e55c 100644
--- a/src/libsodium/randombytes/sysrandom/randombytes_sysrandom.c
+++ b/src/libsodium/randombytes/sysrandom/randombytes_sysrandom.c
@@ -20,8 +20,8 @@
 #include "utils.h"
 
 #ifdef _WIN32
-# include <Windows.h>
-# include <Wincrypt.h>
+# include <windows.h>
+# include <wincrypt.h>
 #endif
 
 typedef struct SysRandom_ {
diff --git a/src/libsodium/sodium/utils.c b/src/libsodium/sodium/utils.c
index bf365ea3..3b9bb6f4 100644
--- a/src/libsodium/sodium/utils.c
+++ b/src/libsodium/sodium/utils.c
@@ -8,8 +8,8 @@
 #include "utils.h"
 #include "randombytes.h"
 #ifdef _WIN32
-# include <Windows.h>
-# include <Wincrypt.h>
+# include <windows.h>
+# include <wincrypt.h>
 #endif
 
 void