Base 64 encoding represents a common scheme for encoding binary into ASCII string format using radix 64. The base64 module is part of the standard library, which means it installs along with Python. Understanding of bytes and strings is critical to this topic and can be reviewed here. This topic explains how to use the various features and number bases of the base64 module.

Up until Python 3.4 came out, base64 encoding and decoding functions only worked with bytes or bytearray types. Now these functions accept any bytes-like object.

Encoding and Decoding Base64

To include the base64 module in your script, you must import it first:

import base64

The base64 encode and decode functions both require a bytes-like object. To get our string into bytes, we must encode it using Python’s built in encode function. Most commonly, the UTF-8 encoding is used, however a full list of these standard encodings (including languages with different characters) can be found here in the official Python Documentation. Below is an example of encoding a string into bytes:

s = "Hello World!"
b = s.encode("UTF-8")

The output of the last line would be:

b'Hello World!'

The b prefix is used to denote the value is a bytes object.

To Base64 encode these bytes, we use the base64.b64encode() function:

import base64
s = "Hello World!"
b = s.encode("UTF-8")
e = base64.b64encode(b)
print(e)

That code would output the following:

b'SGVsbG8gV29ybGQh'

which is still in the bytes object. To get a string out of these bytes, we can use Python’s decode() method with the UTF-8 encoding:

import base64
s = "Hello World!"
b = s.encode("UTF-8")
e = base64.b64encode(b)
s1 = e.decode("UTF-8")
print(s1)

The output would then be:

SGVsbG8gV29ybGQh

If we wanted to encode the string and then decode we could use the base64.b64decode() method:

import base64
# Creating a string
s = "Hello World!"
# Encoding the string into bytes
b = s.encode("UTF-8")
# Base64 Encode the bytes
e = base64.b64encode(b)
# Decoding the Base64 bytes to string
s1 = e.decode("UTF-8")
# Printing Base64 encoded string
print("Base64 Encoded:", s1)
# Encoding the Base64 encoded string into bytes
b1 = s1.encode("UTF-8")
# Decoding the Base64 bytes
d = base64.b64decode(b1)
# Decoding the bytes to string
s2 = d.decode("UTF-8")
print(s2)