So blockchain is made up of hashes that are essentially digital fingerprints. But what is a hash?

Hashing is the process of running data through an algorithm called cryptographic hash function.
A hash is the result of converting a data set of any size or length into a unique sixty four digit code that can only represent that specific data. It is impossible to duplicate the hash value unless you possess exactly the same data.
Unlike encryption, hash algorithms are one way functions. It is not mathematically feasible to reverse a hash function.
This makes them very effective for creating unique digital fingerprints while keeping your data completely private. No matter the size of the data, the hash produced will always have the same number of characters.
Even the slightest edit to a document will produce a vastly different hash.

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