Hash Function

A hash function takes a data like string and outputs a hash, a fixed-size string or number.

E.g MD5 hash for a string “alok” is bad220c335d0c1f53548f6acdb17e265

import hashlib# initializing stringstr2hash = "alok"result = hashlib.md5(str2hash.encode())print(result.hexdigest())bad220c335d0c1f53548f6acdb17e265

Notes

  1. A given file will always have same hash but we can’t go back from hash to original value
  2. Sometime multiple string having same hash value, which is called hash collision.

Use cases of hash map

  1. Unordered map or dictionary : Creating a look up table in programming language.
  2. Preventing man-in-the-middle attack

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