diff --git a/src/zip.rs b/src/zip.rs
index a686a75..714ed53 100644
--- a/src/zip.rs
+++ b/src/zip.rs
@@ -136,24 +136,13 @@ impl UploadedFile {
 
     fn central_directory_header(&self, local_header_offset: usize, hash: u32) -> Vec<u8> {
         let mut header = vec![
-            // Central directory file header signature
-            0x50, 0x4b, 0x01, 0x02,
-            // Made by a "DOS" system supporting version 4.5 - if we
-            // say it's made by a Unix system, then unzip will expect
-            // it to have embedded Unix permission information, and
-            // will set all the files to mode 000 when that's not
-            // present :/
-            45, 0,
+            0x50, 0x4b, 0x01, 0x02, // Central directory file header signature
+            45, 3,                  // Made by a Unix system supporting version 4.5
         ];
         header.append(&mut self.shared_header_fields(Some(hash)));
-        header.append(&mut vec![
-            0, 0, // File comment length: 0
-            0, 0, // Disk number where file starts: 0
-            0, 0, // Internal file attributes: nothing
-            0, 0, 0, 0, // External file attributes: nothing
-            0xff, 0xff, 0xff,
-            0xff, // Relative offset of local file header: placeholder, see ZIP64 data
-        ]);
+        append_0(&mut header, 8); // Comment length, disk number, internal attributes, DOS external attributes
+        append_value(&mut header, 0o100644, 2); // Unix external file attributes: -rw-r--r--
+        append_ff(&mut header, 4); // Relative offset of local file header: placeholder, see ZIP64 data
         header.append(&mut self.name.clone().into_bytes());
         header.append(&mut self.extra_field(local_header_offset));
         header
@@ -179,7 +168,7 @@ fn end_of_central_directory(files: &[UploadedFile]) -> Vec<u8> {
     ];
     append_0(&mut eocd, 7); // pad out the rest of the size field
     eocd.append(&mut vec![
-        45, 0, // Made by a "DOS" system supporting version 4.5, see above
+        45, 3, // Made by a Unix system supporting version 4.5
         45, 0, // Minimum version 4.5 to extract
     ]);
     append_0(&mut eocd, 8); // Two 4-byte disk numbers, both 0