Reposting since it is making some news again!
A Hash is a cryptographic function which converts an input stream of words and letters into an encrypted output of fixed length.
Hashing involves processing the data from a block through a mathematical function, which results in an output (encrypted data) of a fixed length.
Using a fixed length output increases security, since it wont be possible to determine the length of input by simply looking at the length of the output.
For example, hashing the word “Bipins Blogs” or “Rum Pell Still Skin” will both produce an output of the same length.
Also, making even small changes to the input can completely change the output as can be seen from the above diagram.