How do you decode Base64 data in Python?

Base64 encoding is commonly used to represent binary data in a text format, often for data transmission, embedding images, or storing information in a compact way. But how do you decode Base64 data back into its original form in Python? Luckily, Python provides a built-in base64 module that makes this process simple.

1. Using the base64 Module

• Python’s base64 library has a method called b64decode() for decoding.
  

Example:

 import base64

encoded_data = "SGVsbG8gV29ybGQh"

decoded_data = base64.b64decode(encoded_data)

print(decoded_data.decode("utf-8")) # Output: Hello World!

Here, the encoded string is converted back into human-readable text.

2. Decoding Files

• Base64 is also used for files like images or PDFs.
  

Example:

 with open("image.txt", "r") as file:

    encoded = file.read()

decoded = base64.b64decode(encoded)

with open("output.png", "wb") as img:

    img.write(decoded)

This restores the original file from its Base64 version.

Key Points to Remember:

• Always ensure the encoded string length is valid (multiples of 4).
  
• Use .decode("utf-8") if you want to convert the output into a readable string.
  
• Base64 is an encoding, not encryption—it only transforms data, not secures it.
  

In summary, decoding Base64 in Python is straightforward with the base64 module. Whether you’re working with text or files, b64decode() makes it easy to retrieve the original data.