SPUG:Appropriateness of MD5

[Peter Darley]

Friends,
	I have a system that produces reports on large sets of data every night.
Each report is made up of columns of data, the contents of which can change
at times.  I want to create a list of all the individual records that make
up each column, use them to create a string that would uniquely describe the
contents of the report, then create an MD5 digest of it which would be
checked against subsequent digests to see if the contents of the report had
changed and it needed to be re-run.
	My question is this: Is the MD5 digest going to be sensitive enough to
detect the changes?  The 'key' of the report will likely be ~1000-2000
characters before digesting, and I'm a bit woried that a 128 bit digest
won't be unique enough to indicate a change to the 'key'.
	Any suggestions appreciated. :)
Thanks,
Peter Darley