How to use Hashlib in Python- A Complete Guide

Hashlib Python- A Complete Guide

Hashlib is a Python module that implements an interface to different secure hash algorithms and digest algorithms. Hashlib is a secure hash and message digest algorithm library. 

What is Hashlib?

Hashlib is a Python library that provides the SHA-224, SHA-256, SHA-384, SHA-512 hash algorithms. Besides this Hashlib provides the platform optimized versions of MD5 and SHA1. The maintainer of this project is an expert python programmer GregoryPSmth

Why do we need Python Hashlib?

To generate Python secure Hash message, we need to use hashlib python module

How does the Hashlib Python Works?

There are multiple hashing functions present in the Hashlib Python module which takes a variable length of bytes and then it converts it into a sequence of fixed length. The most important thing about these functions is they are all one-way functions and can not be reversed. This means that once we created a hash of a message we can re create our message back from these hashes created by the hashlib python module.

Is it good to use hashlib python for hashing?

Yes it will be very good to use hashlib python module for hashing a message because Hashlib comes in the category of cryptography, in cryptography a hash the algorithm is considered to be better if the original message cannot be decrypted from the hash message that is created by that hash function or algorithm. this is the main rule of cryptography. so in the sense of cryptography we can see that hashlib is most important. 

Why we should use Hashlib Python?

Hashlib Python provides the most secure hash values which is very good in storing sensitive data, like password or bank details so if the database is hacked or something other happens no one will be able to recreate the information from the hash values created by the hashlib python package. Even the site owner will not understand what this sensitive data means. 

Can we use Hashlib Python for storing Passwords?

Yes, Hashlib python is very good if you want to store values for your password instead of the plain password. This means if your database got hacked no one will be able to see the values of the password. 

How to use the Hashlib Python module?

Hashlib Python module provides a few functions which are very handy when we are working with hashing messages. We will discuss them in detail with code samples for better understand these functions.

How to find all the algorithms available in hashlib Module?

we can find all the algorithms available on the system by using the algorithms_available attribute. if we want to find the number of algorithms available in the python hashlib module we can use another attribute alorithms_guranteed. 

Below is the code which will show you all the algorithms available on the system and all the algorithms available in the python hashlib module. the output of the following can be different on different systems. 

import hashlib

sysalgorithms = hashlib.algorithms_available
print("Algorithms on system")
for algo in sysalgorithms:

print("Algorithms available for you")
for algo in modalgos:

How to hash the Whole message with Hashlib Python?

To hash the whole message once we can use the name of the hash function that we are using and we pass the byte string to this function. below is the code which shows how we can use the sha256 algorithm to hash the string message. “b” before the string message means that this is a byte string. 

import hashlib
hash = hashlib.sha256(b"")

How to see the hash of the message with Hashlib Python?

To see the hash created by the algorithm you can use the digest method of the hashlib python module. below is the code which will show you how you can see the hash of the hashed string.

import hashlib
hash = hashlib.sha256(b"")
print('Output:', hash.digest())

# Output: b'\x9d\xe9\xc9\xc6\x93\x0bl\xd3\
#    xba\x18W\x02\x8d\xed\xfd\x0e\x14\x96hG
#    \x99S\xe6\xe7\xec\xf4rQ-\x16\x91\xd8'

The update() method Hashlib Python

There is one constructor method for each type of hash available in the hashlib python package. all the constructor methods return the hash object of the same interface. if we sue the sha1() to create the hash message of the SHA1 algorithm will just return the SHA1 object. Now once we have the object we can feed this hash algorithm object with any strings by just using the update() method which is available in the hashlib. look at the below code how we can use the update method.

import hashlib
hash = hashlib.md5()
hash.update(b"Learn code with alixa")

# Output:b'";:%d\xf6\xb3\xa7\xd8\x8fc\x0e\xb9qBw'

The digest_size and block_size Hashlib Python

Print the size of the digest size and the block size of the hashed messages with the python hashlib package. Below is the code which tells us about the insight of the hashed messages.

import hashlib
hash = hashlib.md5()
# The size of the resulting hash in bytes.
# The internal block size of the hash algorithm in bytes.
# output
# 16
# 64

How to add salt to the hashed Message with hashlib Python module?

To make the hashed message even more strong we can add the salt to the hashed message by using the following code we can create a more secure hashed value.

import hashlib
salt = hashlib.scrypt(b"myPassword",salt=b"salt",n=4,r=2,p=2)

Why is md5 Known as a vulnerable hash algorithm?

It’s vulnerable not because we can get the original value, but because we can get the same hashes for different values, this is proven to be true!

Is there any way to decrypt sha256 except by trying wordlist?

SHA256 is considered a secure hashing algorithm. Therefore, brute-force with wordlist is the only choice we have.

Summary and Conclusion:-

We have learned about the hashlib python package. Although this was a brief description of the hashlib package. if you want to know more about the hashlib you can always have a look at the official documentation of hashlib python. If you are interested in other python tutorials please visit my youtube channel Code with Ali.

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