--- a/src/core/ngx_md5.c
+++ b/src/core/ngx_md5.c
@@ -36,7 +36,7 @@ ngx_md5_update(ngx_md5_t *ctx, const voi
 {
     size_t  used, free;
 
-    used = ctx->bytes & 0x3f;
+    used = (size_t) (ctx->bytes & 0x3f);
     ctx->bytes += size;
 
     if (used) {
@@ -66,7 +66,7 @@ ngx_md5_final(u_char result[16], ngx_md5
 {
     size_t  used, free;
 
-    used = ctx->bytes & 0x3f;
+    used = (size_t) (ctx->bytes & 0x3f);
 
     ctx->buffer[used++] = 0x80;
 
@@ -82,33 +82,33 @@ ngx_md5_final(u_char result[16], ngx_md5
     ngx_memzero(&ctx->buffer[used], free - 8);
 
     ctx->bytes <<= 3;
-    ctx->buffer[56] = ctx->bytes;
-    ctx->buffer[57] = ctx->bytes >> 8;
-    ctx->buffer[58] = ctx->bytes >> 16;
-    ctx->buffer[59] = ctx->bytes >> 24;
-    ctx->buffer[60] = ctx->bytes >> 32;
-    ctx->buffer[61] = ctx->bytes >> 40;
-    ctx->buffer[62] = ctx->bytes >> 48;
-    ctx->buffer[63] = ctx->bytes >> 56;
+    ctx->buffer[56] = (u_char) ctx->bytes;
+    ctx->buffer[57] = (u_char) (ctx->bytes >> 8);
+    ctx->buffer[58] = (u_char) (ctx->bytes >> 16);
+    ctx->buffer[59] = (u_char) (ctx->bytes >> 24);
+    ctx->buffer[60] = (u_char) (ctx->bytes >> 32);
+    ctx->buffer[61] = (u_char) (ctx->bytes >> 40);
+    ctx->buffer[62] = (u_char) (ctx->bytes >> 48);
+    ctx->buffer[63] = (u_char) (ctx->bytes >> 56);
 
     (void) ngx_md5_body(ctx, ctx->buffer, 64);
 
-    result[0] = ctx->a;
-    result[1] = ctx->a >> 8;
-    result[2] = ctx->a >> 16;
-    result[3] = ctx->a >> 24;
-    result[4] = ctx->b;
-    result[5] = ctx->b >> 8;
-    result[6] = ctx->b >> 16;
-    result[7] = ctx->b >> 24;
-    result[8] = ctx->c;
-    result[9] = ctx->c >> 8;
-    result[10] = ctx->c >> 16;
-    result[11] = ctx->c >> 24;
-    result[12] = ctx->d;
-    result[13] = ctx->d >> 8;
-    result[14] = ctx->d >> 16;
-    result[15] = ctx->d >> 24;
+    result[0] = (u_char) ctx->a;
+    result[1] = (u_char) (ctx->a >> 8);
+    result[2] = (u_char) (ctx->a >> 16);
+    result[3] = (u_char) (ctx->a >> 24);
+    result[4] = (u_char) ctx->b;
+    result[5] = (u_char) (ctx->b >> 8);
+    result[6] = (u_char) (ctx->b >> 16);
+    result[7] = (u_char) (ctx->b >> 24);
+    result[8] = (u_char) ctx->c;
+    result[9] = (u_char) (ctx->c >> 8);
+    result[10] = (u_char) (ctx->c >> 16);
+    result[11] = (u_char) (ctx->c >> 24);
+    result[12] = (u_char) ctx->d;
+    result[13] = (u_char) (ctx->d >> 8);
+    result[14] = (u_char) (ctx->d >> 16);
+    result[15] = (u_char) (ctx->d >> 24);
 
     ngx_memzero(ctx, sizeof(*ctx));
 }