diff --git a/include/xlsxwriter/third_party/md5.h b/include/xlsxwriter/third_party/md5.h
index 2da44bf3..8d0844f0 100644
--- a/include/xlsxwriter/third_party/md5.h
+++ b/include/xlsxwriter/third_party/md5.h
@@ -23,23 +23,21 @@
  * See md5.c for more information.
  */
 
-#ifdef HAVE_OPENSSL
-#include <openssl/md5.h>
-#elif !defined(_MD5_H)
-#define _MD5_H
+#ifndef __LXW_MD5_H__
+#define __LXW_MD5_H__
 
 /* Any 32-bit or wider unsigned integer data type will do */
-typedef unsigned int MD5_u32plus;
+typedef unsigned int uint32_t;
 
 typedef struct {
-	MD5_u32plus lo, hi;
-	MD5_u32plus a, b, c, d;
+	uint32_t lo, hi;
+	uint32_t a, b, c, d;
 	unsigned char buffer[64];
-	MD5_u32plus block[16];
-} MD5_CTX;
+	uint32_t block[16];
+} lxw_md5_ctx;
 
-extern void MD5_Init(MD5_CTX *ctx);
-extern void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size);
-extern void MD5_Final(unsigned char *result, MD5_CTX *ctx);
+extern void lxw_md5_init(lxw_md5_ctx *ctx);
+extern void lxw_md5_update(lxw_md5_ctx *ctx, const void *data, unsigned long size);
+extern void lxw_md5_final(unsigned char *result, lxw_md5_ctx *ctx);
 
 #endif
diff --git a/src/worksheet.c b/src/worksheet.c
index 982a82e9..f45d2e53 100644
--- a/src/worksheet.c
+++ b/src/worksheet.c
@@ -2949,7 +2949,7 @@ _get_image_properties(lxw_object_properties *image_props)
     unsigned char signature[4];
 #ifndef USE_NO_MD5
     uint8_t i;
-    MD5_CTX md5_context;
+    lxw_md5_ctx md5_context;
     size_t size_read;
     char buffer[LXW_IMAGE_BUFFER_SIZE];
     unsigned char md5_checksum[LXW_MD5_SIZE];
@@ -2987,16 +2987,16 @@ _get_image_properties(lxw_object_properties *image_props)
      * images to reduce the xlsx file size.*/
     rewind(image_props->stream);
 
-    MD5_Init(&md5_context);
+    lxw_md5_init(&md5_context);
 
     size_read = fread(buffer, 1, LXW_IMAGE_BUFFER_SIZE, image_props->stream);
     while (size_read) {
-        MD5_Update(&md5_context, buffer, size_read);
+        lxw_md5_update(&md5_context, buffer, size_read);
         size_read =
             fread(buffer, 1, LXW_IMAGE_BUFFER_SIZE, image_props->stream);
     }
 
-    MD5_Final(md5_checksum, &md5_context);
+    lxw_md5_final(md5_checksum, &md5_context);
 
     /* Create a 32 char hex string buffer for the MD5 checksum. */
     image_props->md5 = calloc(1, LXW_MD5_SIZE * 2 + 1);
diff --git a/third_party/md5/md5.c b/third_party/md5/md5.c
index b235e17a..73f1914b 100644
--- a/third_party/md5/md5.c
+++ b/third_party/md5/md5.c
@@ -79,16 +79,16 @@
  */
 #if defined(__i386__) || defined(__x86_64__) || defined(__vax__)
 #define SET(n) \
-	(*(MD5_u32plus *)&ptr[(n) * 4])
+	(*(uint32_t *)&ptr[(n) * 4])
 #define GET(n) \
 	SET(n)
 #else
 #define SET(n) \
 	(ctx->block[(n)] = \
-	(MD5_u32plus)ptr[(n) * 4] | \
-	((MD5_u32plus)ptr[(n) * 4 + 1] << 8) | \
-	((MD5_u32plus)ptr[(n) * 4 + 2] << 16) | \
-	((MD5_u32plus)ptr[(n) * 4 + 3] << 24))
+	(uint32_t)ptr[(n) * 4] | \
+	((uint32_t)ptr[(n) * 4 + 1] << 8) | \
+	((uint32_t)ptr[(n) * 4 + 2] << 16) | \
+	((uint32_t)ptr[(n) * 4 + 3] << 24))
 #define GET(n) \
 	(ctx->block[(n)])
 #endif
@@ -97,11 +97,11 @@
  * This processes one or more 64-byte data blocks, but does NOT update the bit
  * counters.  There are no alignment requirements.
  */
-static const void *body(MD5_CTX *ctx, const void *data, unsigned long size)
+static const void *body(lxw_md5_ctx *ctx, const void *data, unsigned long size)
 {
 	const unsigned char *ptr;
-	MD5_u32plus a, b, c, d;
-	MD5_u32plus saved_a, saved_b, saved_c, saved_d;
+	uint32_t a, b, c, d;
+	uint32_t saved_a, saved_b, saved_c, saved_d;
 
 	ptr = (const unsigned char *)data;
 
@@ -204,7 +204,7 @@ static const void *body(MD5_CTX *ctx, const void *data, unsigned long size)
 	return ptr;
 }
 
-void MD5_Init(MD5_CTX *ctx)
+void lxw_md5_init(lxw_md5_ctx *ctx)
 {
 	ctx->a = 0x67452301;
 	ctx->b = 0xefcdab89;
@@ -215,9 +215,9 @@ void MD5_Init(MD5_CTX *ctx)
 	ctx->hi = 0;
 }
 
-void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size)
+void lxw_md5_update(lxw_md5_ctx *ctx, const void *data, unsigned long size)
 {
-	MD5_u32plus saved_lo;
+	uint32_t saved_lo;
 	unsigned long used, available;
 
 	saved_lo = ctx->lo;
@@ -255,7 +255,7 @@ void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size)
 	(dst)[2] = (unsigned char)((src) >> 16); \
 	(dst)[3] = (unsigned char)((src) >> 24);
 
-void MD5_Final(unsigned char *result, MD5_CTX *ctx)
+void lxw_md5_final(unsigned char *result, lxw_md5_ctx *ctx)
 {
 	unsigned long used, available;
 
diff --git a/third_party/md5/md5.h b/third_party/md5/md5.h
index 2da44bf3..8d0844f0 100644
--- a/third_party/md5/md5.h
+++ b/third_party/md5/md5.h
@@ -23,23 +23,21 @@
  * See md5.c for more information.
  */
 
-#ifdef HAVE_OPENSSL
-#include <openssl/md5.h>
-#elif !defined(_MD5_H)
-#define _MD5_H
+#ifndef __LXW_MD5_H__
+#define __LXW_MD5_H__
 
 /* Any 32-bit or wider unsigned integer data type will do */
-typedef unsigned int MD5_u32plus;
+typedef unsigned int uint32_t;
 
 typedef struct {
-	MD5_u32plus lo, hi;
-	MD5_u32plus a, b, c, d;
+	uint32_t lo, hi;
+	uint32_t a, b, c, d;
 	unsigned char buffer[64];
-	MD5_u32plus block[16];
-} MD5_CTX;
+	uint32_t block[16];
+} lxw_md5_ctx;
 
-extern void MD5_Init(MD5_CTX *ctx);
-extern void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size);
-extern void MD5_Final(unsigned char *result, MD5_CTX *ctx);
+extern void lxw_md5_init(lxw_md5_ctx *ctx);
+extern void lxw_md5_update(lxw_md5_ctx *ctx, const void *data, unsigned long size);
+extern void lxw_md5_final(unsigned char *result, lxw_md5_ctx *ctx);
 
 #endif