Applications of one-way hashes

• Integrity checks

• • No matter how much data you run through md5 you get a hash of the same size.
  • Despite recent changes in understanding, It is infeasible for an attacker to modify a file and leave it with the same MD5 checksum.
  • Using SHA1 or SHA256 instead of md5 is still probably a good idea.

• Password storage

• • Password files with clear text password in them are a very attractive target.