WHAT IS Hashing?

                                              Hashing is the conversion of strings

into a usually short, pre-defined length value or key which represents the original data. It is used to store, index and retrieve data in a database because it is a lot faster to search for an item using shorter hashed key than to search for it using the original data. many encryption algorithms use hashing.

What is Hash-Table?

It is ,basically an array which links with its key specific data value a key. For example, say we want to build a database which stores the profile data of all users of a food delivery app service; in that case, the keys would be the names of the users or their user ID and the values would be their a structure holding their profile information, including things like their last name, gender, age, country, status, etc.

Hash Function

It is a function which converts given data into small integer value. The hash table then uses the integer value as index. In simple terms, it maps a big number or string to a smaller integer which can be used as an index in the hash table. 

Two methods:

• Hashing by division (mod method)
  
• Hashing by multiplication

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Applications Of Hashing:

• A Data Structure - Hash Table square measure used as informational knowledge an information} structure as a result of it stores data in Associate in Nursing associative manner. in a very hash table, arrays square measure wont to store information, wherever every information worth is mapped to its own distinctive index worth. Accessing becomes extremely quick if we all know the index of the required information. Thus, it becomes a knowledge structure wherever search and insertion operations square measure in no time regardless of the scale of the information. Hash Table uses arrays as a data-storage medium and uses hashing to get an index wherever a part is to be inserted or is to be set from. To learn more, Click here.
• ENCRYPTION- When WE use any on-line web site which needs a user login, we tend to enter our E-mail and watchword to manifest that the account we tend to try to use belongs to us. once the watchword is entered, a hash of the watchword is computed that is then sent to the server for verification of the watchword. The passwords keep on the server are literally computed hash values of the initial passwords. this is often done to make sure that once the watchword is distributed from shopper to server, thus no middle man will sniff into the watchword sent over network To learn more, Click here.
• Linking of FILE NAME and PATH- When moving through files on our native system, we have a tendency to observe 2 terribly crucial parts of a file i.e. name and file path. so as to store the correspondence between name and file path the system uses a map (filename, file path) that is enforced employing a hash table. To learn more, Click here.
• Message Digest- A message digest might be a cryptologic hash operate containing a string of digits created by a unifacial hashing formula. Specific files containing the protected works are represented by Message digest hash numbers. One message digest is allotted to specific data content. it'll reference a modification created deliberately or accidentally, but it prompts the owner to identify the modification equally as a result of the individual(s) making the modification. Message digests unit of measurement recursive numbers. To learn more, Click here.