MD5 is a frequently used one-way hash algorithm, it is commonly used in following situations:Check data integrity. We take hash of the data stored in two different places and compare them. If the hash results are the same, then there is no need to check the actual data. This utilizes the collision-resistant feature. Two different data block will have little chance that their hash values will be the same. Many data service providers use such technique to check repeated data to avoild repeating uploading. Also, it is frequently used in transferring file to ensure the file is not modified during ...

A given hash uniquely represents a file, or any arbitrary collection of data. At least in theory. This is a 128-bit MD5 hash you're looking at above, so it can represent at most 2128 unique items, or 340 trillion trillion trillion. In reality the usable space is substantially less; you can start seeing significant collisions once you've filled half the space, but half of an impossibly large number is still impossibly large.Back in 2005, I wondered about the difference between a checksum and a hash. You can think of a checksum as a person's full name: Eubediah Q. Horsefeathers. It's a shortcut ...