How to Generate Python File checksum value

by

A checksum value for a file can be created using any of a number of hashing algorithms, including MD5, SHA-1, SHA-256, and SHA-512. Each algorithm generates a hash value of a specified size that is specific to the input file. The required level of security and the desired size of the checksum value determine the algorithm to choose.

What is File checksum value ?

The content of a file can be uniquely identified by its checksum value. Typically, it is produced by a hashing technique that creates a fixed-size digital signature of the file’s contents. The checksum value can be used to determine a file’s integrity, or whether it has been altered or corrupted.

Steps to Generate File checksum value in Python

To generate file checksum value in python you can use hashlib module, Here are general steps :

  1. import the module named hashlib.
  2. Use the open() method in binary mode to open the file.
  3. Update the hash object using the update() function after reading the file’s content in sections.
  4. Use the hexdigest() function to obtain the hash’s hexadecimal digest.

Implementation

import hashlib

def generate_file_checksum(file_path, hash_algorithm="sha256"):
    # initialize the hash object for the specified algorithm
    hash_object = hashlib.new(hash_algorithm)

    # open the file in binary mode
    with open(file_path, "rb") as f:
        # read the file content in chunks
        for chunk in iter(lambda: f.read(4096), b""):
            # update the hash object with the chunk
            hash_object.update(chunk)

    # get the hexadecimal digest of the hash
    checksum_value = hash_object.hexdigest()

    return checksum_value

The generate file checksum() function in this example accepts two arguments: hash algorithm, which determines the hash algorithm to employ, and file path, which specifies the path to the file for which the checksum is to be generated (default is SHA256).

You can call this function like this 

file_path = "path/to/your/file"
checksum_value = generate_file_checksum(file_path)
print(checksum_value)

Output

2f184356d8a89e3af925e52901f3ecb1d49c1f30b207f32c0862e78f0f5a5812

Key Points About File Check Sum Value

  • A hashing technique that creates a fixed-size digital signature of the file’s content produces a file checksum value, a distinctive identifier of the content of a file.
  • The checksum value can be used to determine a file’s integrity, or whether it has been altered or corrupted.
  • To verify that a file has been downloaded or transmitted successfully across a network, it is usual practise to produce a checksum value for the file and compare it with the expected checksum value.
  • The hashing methods MD5, SHA-1, SHA-256, and SHA-512 are frequently employed to create file checksum values.
  • A file checksum value is often shown as a fixed-length hexadecimal string that is specific to the contents of the file and the hashing algorithm employed.
  • Opening the file in binary mode, reading the content of the file in chunks, updating the hash object using the content, and obtaining the hexadecimal digest of the hash are the steps involved in creating a file checksum value.
  • In many different applications, such as software updates, file sharing, and digital signatures, file checksum values are frequently employed to guarantee the veracity and integrity of the data being conveyed.

Hope You like this post

Leave a Comment