Hash software essentials

There certain rules and requirements for a hashing algorithm in order to be useful

The first concept that will help you through understanding these rules, is to imagine a fingerprint:

1. Time independent(& deterministic)
   1. A finger print that changes every time, doesn’t help in identifying the person, since it’s always something new
   2. So we want the person or node to be identified and unique, from other nodes or person
2. One way
   1. You can’t figure details about a person just by their fingerprint, but you can get a fingerprint by the person
   2. So you do not want the content of your node to be decodable through the hash, but you do need the content to be hashed
3. Fast computation
   1. Time is very important here, and you don’t want the hashing take a lot of time
4. The avalanche effect
   1. Even by the tiniest change possible in the content, the hash has to be completely different, compared to the previous state
5. Collisions
   1. collision means the situation of dealing with two of the same hash
   2. Although it is possible just like in fingerprints, to find two of the same, but since it is very unlikely, it’s ok
   3. But what if it was artificial, which would be meant to attack with a certain information that the attacker has got, that you got to manage and prepare

There are many examples already such as

• SHA2
• SHA256

and many more

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