Hash

Hash function (or hash algorithm) is a process by which a document (ie. a piece of data or file) is processed into a small piece of data (usually 32 bytes) which looks completely random, and from which no meaningful data can be recovered about the document, but which has the important property that the result of hashing one particular document is always the same. Additionally, it is crucially important that it is computationally infeasible to find two documents that have the same hash.