home *** CD-ROM | disk | FTP | other *** search
- <title>WWW Authentication</title>
- <body>
- <h1>WWW Authentication</h1>
-
- Information providers may decide to protect their pages by password in
- order to restrict who can see them. (eg. <a
- "href=http://www.acorn.co.uk/acorn/clan/private/Home">Acorn's Clan only
- pages</a>). To do this they construct a password file at the server end and
- put an access control file in the clan home directory, giving a symbolic name
- by which any files under that directory need to be accessed. Acorn chose
- "AcornClan" as their authentication 'realm' . This means that if you send a
- normal request to www.acorn.co.uk asking for one of the clan pages, you will
- get back:
-
- <pre>
-
- HTTP/1.0 401 Unauthorized
- Server: CERN/3.0 (or similar)
- Date: .... etc. etc.
- WWW-Authenticate: Basic "AcornClan"
- Content-Type: text/html
-
- <title>Unauthorized</title>
- <h1>401 Unauthorized</h1>Your browser does not appear to support user
- authentication.
-
- </pre>
-
- At which point, ArcWeb will prompt you for a user name and password
- which will satisfy the "AcornClan" realm of www.acorn.co.uk. So you
- enter the user name and password and press RETURN and ArcWeb will
- resend the request but include an extra header. For example,
- suppose I enter user name 'Aladdin' and password 'open sesame', the
- following header will be sent with the repeated request:
-
- <pre>
-
- Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==
-
- </pre>
-
- where it has converted the user name and password to a simple non-clear
- text format (note: this is <em>NOT SECURE</em> - any base64 decoder can decode
- that string I've given above back into 'Aladdin:open sesame') Note
- that the authentication information is cached by ArcWeb until it
- quits (unless you set the option in the configuration window to stop it
- deleting the cache upon exit), and that if you attempt to access another
- page under the clan hierarchy, then ArcWeb will speculatively add the
- cached authentication information to the original request in an attempt
- to pre-empt any challenge.
-
- <hr>
- <address>Stewart Brodie<br>21st November 1995</address>
-