How to Encode or Decode a base64 String on Linux

Base64 is a binary-to-text encoding scheme that is commonly used to encode binary data, especially when that data needs to be sent over media that are designed to handle text. T

This encoding process also helps us to ensure that the data remains intact without alteration during transport. On the other hand, decoding is the process of converting base64 encoded data back into its original binary format.

In this tutorial, we will explore the various tools and methods we can use to encode and decode base64 data in the Linux ecosystem

Method 1 - Using the Base64 Utility

The base64 utility is a command-line utility that can encode and decode base64 strings. It is typically pre-installed on most Linux distributions.

Encoding

To encode a string, you can echo the string and pipe it to the base64 command. For example:

echo -n 'Hello World' | base64

The -n option tells echo not to output the trailing newline.

The resulting string will be an base64 encoded string as:

SGVsbG8gV29ybGQ=

Decoding

To decode a base64 string, you use the -d or --decode option:

echo 'SGVsbG8gV29ybGQ=' | base64 --decode

The output will be the original string.

Hello World

Method 2 - Using the OpenSSL Utility

OpenSSL is a robust, full-featured open-source toolkit that implements the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols.

It also includes a command-line utility that can be used for various purposes, including encoding and decoding base64 strings.

Encoding

To encode a string, you can echo the string and pipe it to the openssl base64 command:

echo -n 'Hello World' | openssl base64

The result:

SGVsbG8gV29ybGQ=

Decoding

To decode a string, you use the -d or --decode option:

echo 'SGVsbG8gV29ybGQ=' | openssl base64 -d

Output:

Hello World

Method 3: Using Python

We can also use Python encoding and decoding functionality to encode and decode base64 strings.

Encoding

Open a Python interactive shell by typing python or python3 in your terminal.

Import the base64 module and use the b64encode method to encode a string:

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

The code above will return a byte string:

b'SGVsbG8gV29ybGQ='

Decoding

Use the b64decode method to decode a base64 string:

import base64
decoded = base64.b64decode(b'SGVsbG8gV29ybGQ=')
print(decoded)

The result:

 b'Hello World'

If you want to convert this byte string to a regular string, you can use the decode method of the byte string:

print(decoded.decode('utf-8'))

This will output the string Hello World.

Conclusion

In this tutorial, we covered how to encode and decode a base64 string on Linux using the base64 utility, the openssl utility, and Python.