add note about directories never being encrypted

Author: armijnhemel

testdata/readme.password

@@ -80,6 +80,66 @@ $ du -h dir/bar
 0	dir/bar
 ```
 
+Directories seem to be not encrypted, so they can always be created, as can
+be seen in the field `file security status` when using `zipinfo` on a file and
+searching for a directory entry:
+
+```
+Archive:  zip_password.zip
+There is no zipfile comment.
+
+End-of-central-directory record:
+-------------------------------
+
+  Zip archive file size:                       482 (00000000000001E2h)
+  Actual end-cent-dir record offset:           460 (00000000000001CCh)
+  Expected end-cent-dir record offset:         460 (00000000000001CCh)
+  (based on the length of the central directory and its expected offset)
+
+  This zipfile constitutes the sole disk of a single-part archive; its
+  central directory contains 3 entries.
+  The central directory is 231 (00000000000000E7h) bytes long,
+  and its (expected) offset in bytes from the beginning of the zipfile
+  is 229 (00000000000000E5h).
+
+
+Central directory entry #1:
+---------------------------
+
+  dir/
+
+  offset of local header from start of archive:   0
+                                                  (0000000000000000h) bytes
+  file system or operating system of origin:      Unix
+  version of encoding software:                   3.0
+  minimum file system compatibility required:     MS-DOS, OS/2 or NT FAT
+  minimum software version required to extract:   1.0
+  compression method:                             none (stored)
+  file security status:                           not encrypted
+  extended local header:                          no
+  file last modified on (DOS date/time):          2026 Jan 15 21:15:18
+  file last modified on (UT extra field modtime): 2026 Jan 15 21:15:18 local
+  file last modified on (UT extra field modtime): 2026 Jan 15 20:15:18 UTC
+  32-bit CRC value (hex):                         00000000
+  compressed size:                                0 bytes
+  uncompressed size:                              0 bytes
+  length of filename:                             4 characters
+  length of extra field:                          24 bytes
+  length of file comment:                         0 characters
+  disk number on which file begins:               disk 1
+  apparent file type:                             binary
+  Unix file attributes (040755 octal):            drwxr-xr-x
+  MS-DOS file attributes (10 hex):                dir
+
+  The central-directory extra field contains:
+  - A subfield with ID 0x5455 (universal time) and 5 data bytes.
+    The local extra field has UTC/GMT modification/access times.
+  - A subfield with ID 0x7875 (Unix UID/GID (any size)) and 11 data bytes:
+    01 04 e8 03 00 00 04 e8 03 00 00.
+
+  There is no file comment.
+```
+
 Other encryption methods are stronger. Depending on the encryption method the
 encryption bit flag might or might not be set. For example: for AE-x it will
 be set (APPENDIX E), while for other encryption methods it might not. The flag