Python base64 Module

The base64 module in Python provides functions for encoding binary data to a base64-encoded string and decoding a base64-encoded string back to binary data. Base64 is commonly used for encoding binary data to store and transfer over media that are designed to deal with text.

Table of Contents

1. Introduction
2. Key Functions
   • base64.b64encode
   • base64.b64decode
   • base64.standard_b64encode
   • base64.standard_b64decode
   • base64.urlsafe_b64encode
   • base64.urlsafe_b64decode
   • base64.b32encode
   • base64.b32decode
   • base64.b16encode
   • base64.b16decode
3. Examples
   • Basic Base64 Encoding and Decoding
   • URL-Safe Base64 Encoding and Decoding
   • Base32 Encoding and Decoding
   • Base16 Encoding and Decoding
4. Real-World Use Case
5. Conclusion
6. References

Introduction

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format by translating it into a radix-64 representation. The base64 module in Python provides functions to perform base64 encoding and decoding.

Key Functions

base64.b64encode

Encodes binary data to a base64-encoded string.

import base64

encoded = base64.b64encode(b'Hello, World!')
print(encoded)

Output:

b'SGVsbG8sIFdvcmxkIQ=='

base64.b64decode

Decodes a base64-encoded string back to binary data.

import base64

decoded = base64.b64decode(b'SGVsbG8sIFdvcmxkIQ==')
print(decoded)

Output:

b'Hello, World!'

base64.standard_b64encode

Encodes binary data to a standard base64-encoded string.

import base64

encoded = base64.standard_b64encode(b'Hello, World!')
print(encoded)

Output:

b'SGVsbG8sIFdvcmxkIQ=='

base64.standard_b64decode

Decodes a standard base64-encoded string back to binary data.

import base64

decoded = base64.standard_b64decode(b'SGVsbG8sIFdvcmxkIQ==')
print(decoded)

Output:

b'Hello, World!'

base64.urlsafe_b64encode

Encodes binary data to a URL-safe base64-encoded string.

import base64

encoded = base64.urlsafe_b64encode(b'Hello, World!')
print(encoded)

Output:

b'SGVsbG8sIFdvcmxkIQ=='

base64.urlsafe_b64decode

Decodes a URL-safe base64-encoded string back to binary data.

import base64

decoded = base64.urlsafe_b64decode(b'SGVsbG8sIFdvcmxkIQ==')
print(decoded)

Output:

b'Hello, World!'

base64.b32encode

Encodes binary data to a base32-encoded string.

import base64

encoded = base64.b32encode(b'Hello, World!')
print(encoded)

Output:

b'JBSWY3DPEBLW64TMMQ======'

base64.b32decode

Decodes a base32-encoded string back to binary data.

import base64

decoded = base64.b32decode(b'JBSWY3DPEBLW64TMMQ======')
print(decoded)

Output:

b'Hello, World!'

base64.b16encode

Encodes binary data to a base16-encoded string.

import base64

encoded = base64.b16encode(b'Hello, World!')
print(encoded)

Output:

b'48656C6C6F2C20576F726C6421'

base64.b16decode

Decodes a base16-encoded string back to binary data.

import base64

decoded = base64.b16decode(b'48656C6C6F2C20576F726C6421')
print(decoded)

Output:

b'Hello, World!'

Examples

Basic Base64 Encoding and Decoding

import base64

# Encode data
data = b'Hello, World!'
encoded = base64.b64encode(data)
print('Encoded:', encoded)

# Decode data
decoded = base64.b64decode(encoded)
print('Decoded:', decoded)

Output:

Encoded: b'SGVsbG8sIFdvcmxkIQ=='
Decoded: b'Hello, World!'

URL-Safe Base64 Encoding and Decoding

import base64

# Encode data
data = b'Hello, World!'
encoded = base64.urlsafe_b64encode(data)
print('Encoded:', encoded)

# Decode data
decoded = base64.urlsafe_b64decode(encoded)
print('Decoded:', decoded)

Output:

Encoded: b'SGVsbG8sIFdvcmxkIQ=='
Decoded: b'Hello, World!'

Base32 Encoding and Decoding

import base64

# Encode data
data = b'Hello, World!'
encoded = base64.b32encode(data)
print('Encoded:', encoded)

# Decode data
decoded = base64.b32decode(encoded)
print('Decoded:', decoded)

Output:

Encoded: b'JBSWY3DPEBLW64TMMQ======'
Decoded: b'Hello, World!'

Base16 Encoding and Decoding

import base64

# Encode data
data = b'Hello, World!'
encoded = base64.b16encode(data)
print('Encoded:', encoded)

# Decode data
decoded = base64.b16decode(encoded)
print('Decoded:', decoded)

Output:

Encoded: b'48656C6C6F2C20576F726C6421'
Decoded: b'Hello, World!'

Real-World Use Case

Encoding Binary Data for HTTP Transmission

When transmitting binary data over HTTP, it is common to encode the data using base64 to ensure it remains intact during transport.

import base64

def encode_for_http(data):
    return base64.urlsafe_b64encode(data).decode('utf-8')

def decode_from_http(data):
    return base64.urlsafe_b64decode(data.encode('utf-8'))

binary_data = b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00\x10'
encoded_data = encode_for_http(binary_data)
print('Encoded for HTTP:', encoded_data)

decoded_data = decode_from_http(encoded_data)
print('Decoded from HTTP:', decoded_data)

Output:

Encoded for HTTP: iVBORw0KGgoAAAANSUhEUgAA
Decoded from HTTP: b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00\x10'

Conclusion

The base64 module in Python provides a convenient way to encode and decode binary data to and from base64 encoding. This is particularly useful for transmitting binary data over text-based protocols such as HTTP.

References

• Python base64 module documentation