A few more changes for encryption. Add test that encrypted file can be read.
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index c07549d..3493a14 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -2056,12 +2056,21 @@
Method used for encryption when the buffer is written to a file:
*pkzip*
0 PkZip compatible method. A weak kind of encryption.
- backwards compatible with Vim 7.2 and older.
+ Backwards compatible with Vim 7.2 and older.
*blowfish*
- 1 Blowfish method. Strong encryption. Not compatible
- with Vim 7.2 and older.
+ 1 Blowfish method. Strong encryption. Requires Vim 7.3
+ or later, files can NOT be read by Vim 7.2 and older.
+ This adds a "seed" to the file, every time you write
+ the file the encrypted bytes will be different.
+
When reading an encrypted file 'cryptmethod' will be set automatically
- to detected method for the file being read.
+ to the detected method of the file being read. Thus if you write it
+ without changing 'cryptmethod' the same method will be used.
+ Changing 'cryptmethod' does not mark the file as modified, you have to
+ explicitly write it when not making modifications.
+ Also see |:X|.
+ When a new encryption method is added in a later version of Vim, and
+ the current version does not recognize it, you will get *E821* .
*'cscopepathcomp'* *'cspc'*