[VPM] checksum hash questions

[Jer A]

hello all

I am a newbie in the following area:

these are not really perl questions, but I think some of you would have an 
answer:)

can a file checksum hash, differ if a char is changed in a text file, even 
though the length of the file/string is still the same?

how long does it take to create a checksum hash of a text file that is only 
about 1KB?

what type of checksum hash would you recommend that meets speed and genuine 
file-fingerprinting.

Thanks in advance for all your help.

Jeremy A.