Blockchain

What is Hashing?

Hashing is simply passing some data through a formula that produces a result, called a hash. That hash is usually a string of characters and the hashes generated by a formula are always the same length, regardless of how much data you feed into it. For example, the MD5 formula always produces 32 character-long hashes. Regardless of whether you feed in the entire text of MOBY DICK or just the letter C, you’ll always get 32 characters back.

Hashing is One-Way

Hashing works in one direction only – for a given piece of data, you’ll always get the same hash BUT you can’t turn a hash back into its original data. If you need to go in two directions, you need encrypting, rather than hashing.

With encrypting you pass some data through an encryption formula and get a result that looks something like a hash, but with the biggest difference being that you can take the encrypted result, run it through a decryption formula and get your original data back.

Remember, hashing is different – you can’t get your original data back simply by running a formula on your hash (a bit about how to hack these, though, in a moment).

To salt a hash, simply append a known value to the string before you hash it. For example, if before it’s stored in a database every password is salted with the string ‘dog’, it will likely not be found in online databases. So, password salted with dog (i.e. passworddog) and then run through the md5 calculator becomes 854007583be4c246efc2ee58bf3060e6.

Reference:

 https://www.edureka.co/blog/interview-questions/blockchain-interview-questions/

https://dataspace.com/big-data-applications/what-does-it-mean-to-hash-data/