Shorter checksum than MD5

[Mercuro]

Hello

i'm looking for a simple way to checksum my data. 
  The data is 70 bytes long per record, so a 32 
byte hex md5sum would increase the size of my 
mysql db a lot.

I'm looking for something that is 5 bytes long, 
for the moment i'm just taking a part of the hex 
md5 sum (like this: checksum = md5sum[3:8]).  I 
don't have any duplicates, and I have over 100000 
records, but i'm not sure for the future...


Can anybody give me something better?  Or point me 
to some website?


thx!!


PS: I use this checksum to periodically compare 2 
versions of this DB, which are on 2 sides of a 
slow internet connection.  My hope is to keep down 
unneeded traffic between the 2 servers.