significance of spaces
yanek at novavax.nova.edu
Thu Dec 24 11:13:41 PST 1992
> of view to MD5 the same, but he noted that this isn't a problem in
> practice because humans don't get much information out of the presense of
> multiple spaces versus one space.
This is true for most text, like this message. But sometimes people
send messages where spacing is VERY important:
This is especially true of tables such as this one:
Name Yes No
If the signature algorithm disregarded spaces, the X's could be moved
from one column to the other without affecting the signature.
I know that this information COULD have been represented as:
But sometimes people use the other format. Another solution is to
surround all significant spaces with some other character, such
as the vertical bar:
|Name | Yes | No |
|Smith | X | |
|Jones | | X |
|Brown | | X |
|Xyzzy | X | |
If this were done, an X could not be moved without affecting the signature
even if tabs/spaces were insignificant.
The point is that if whitespace is made insignificant, the users must be
educated about it, and trained to use one of the two last formats
instead of the first one.
Yanek Martinson mthvax.cs.miami.edu!safe0!yanek uunet!medexam!yanek
this address preferred -->> yanek at novavax.nova.edu <<-- this address preferred
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