|Hide Information in Plain Sight - B.
Douglas Wake and William C. Wake
|Sometimes we have information that is
potentially useful or important, but is not normally of interest.
This pattern discusses when and how to hide this information in
- Information is designed using a high format and a powerful
(often new) tool.
- Information is viewed in a low format by a less powerful (often
previously existing) tool.
- Translating from high to low form loses information - we can't
easily translate back from low to high form.
- The high form is retained for future modification.
- The low form may be treated as read-only.
"Hide" high-form information in the low-form object, in such a
way that the low-form tool or the user can ignore the hidden
The low form is read-only, because low-level tools will not know
enough to manipulate the information in the high form. (If they
did, they'd be high-form tools in disguise.) The hidden information
need not be a complete replication of all high-form information; it
might be just enough information to locate the high-form
- Netscape Navigator. (See http://www.netscape.com). Navigator's
page can be set up to display the URL on the printed page. Then,
the printed form is the low form, but it contains the URL that can
be used to locate the high form.
- MIME mail. (N. Freed and N. Borenstein, RFC 2045, "Multipurpose
Internet Mail Extensions (MIME) Part One: Format of Internet
Message Bodies," November, 1996.) The MIME data format allows for
complex mail messages that contain alternative formats for a single
message. A complete MIME mail reader might support display of all
forms of a message. A mail reader with minimal MIME support might
display the plain ASCII version of a message, and ignore the other
forms. A mail reader unaware of MIME might display all parts of the
MIME message (which would include the simple ASCII form).
- Digital watermarks. (Ref??) A museum with images might freely
distribute low-resolution versions of its images, including a
visible watermark that identifies the source of the image. The
museum might sell a high-resolution version containing an invisible
watermark that would allow detection of illegal re-distribution of
- XEROX PARC's XAX system. (W. Johnson et al., "Bridging the
paper and electronic worlds: The paper user interface," Proceedings
of INTERCHI, 1993, pp. 507-512, ACM, April, 1993.) The XAX system
encodes information about a document in glyphs that are "not
visually distracting when embedded in a paper document." This lets
them move from the low-level paper form up to high-level structured
[Originally written November, 1997.]