Putting a password on an image
ImageSafe allows a password to be specified for an image. The applet created can then only be
viewed by someone who has a corresponding small file (about 1300 bytes) installed on
their computer and which their browser can locate. This small password file is generated
automatically by ImageSafe
Specifying the password
Select the option to use a password and then enter a password into the password box.
Passwords can be any length and contain any characters but should not be blank.
Once the password is entered any ImageSafe applet subsequently created will require
the presence of a password file to be seen.
Anonymity of password files
It should be emphasized that a password file is anonymous. It does not identify in any way
the origin of the password file or any information about the person or computer
that created it.
It only provides validation that an image or set of images were protected with a
particular password.
Generating password files
To generate the password file, set a password and press the "Create password" button.
Select a name for the password file and save it. The file must have a ".jar" suffix.
When the authorized viewer of your images receives the file, perhaps by e-mail, they
can put it anywhere on their disk but the browser finds it by referring to the
"classpath" environment variable.
Telling the browser about a password file
Let's suppose the password file is called "access.jar" and is to be found
on a PC's disk as "c:\files\access.jar"
On a windows95/98 system the "autoexec.bat" file should then contain the line
set classpath=c:\files\access.jar
After rebooting this classpath setting will kick in and all images created with
THE SAME password as that used to create the password file can be viewed.
Password file interference
There is a one in one hundred chance that two password files on
a single computer could interfere with one another. If this happens the authorizing
password file is masked by another different password file. The result is that images can't
be viewed even though
access is authorized. The solution is to re-create the password file again. Just re-creating without changing
the password should fix the problem. Let the author know if the odds of one in a hundred are two high. There is a fix
which involves downloading a larger version of the ImageSafe product.
The password valid-until date
It's sometimes desirable to permit access but only for a limited time. A password file can
be given a "valid-until" date. After this date the password file generated with this
option set, will not work any more. Many different password files can be created with different
view-by dates but the same password.