markdown_files/Base_64_Encoding.md

metadata

title: Base 64 Encoding
original_url: https://tds.s-anand.net/#/base64-encoding?id=base-64-encoding
downloaded_at: '2025-06-08T23:27:25.543180'

Base 64 Encoding

Base64 is a method to convert binary data into ASCII text. It’s essential when you need to transmit binary data through text-only channels or embed binary content in text formats.

Watch this quick explanation of how Base64 works (3 min):

Here’s how it works:

• It takes 3 bytes (24 bits) and converts them into 4 ASCII characters
• … using 64 characters: A-Z, a-z, 0-9, + and / (padding with = to make the length a multiple of 4)
• There’s a URL-safe variant of Base64 that replaces + and / with - and _ to avoid issues in URLs
• Base64 adds ~33% overhead (since every 3 bytes becomes 4 characters)

Common Python operations with Base64:

import base64

# Basic encoding/decoding
text = "Hello, World!"
# Convert text to base64
encoded = base64.b64encode(text.encode()).decode()  # SGVsbG8sIFdvcmxkIQ==
# Convert base64 back to text
decoded = base64.b64decode(encoded).decode()        # Hello, World!
# Convert to URL-safe base64
url_safe = base64.urlsafe_b64encode(text.encode()).decode()  # SGVsbG8sIFdvcmxkIQ==

# Working with binary files (e.g., images)
with open('image.png', 'rb') as f:
    binary_data = f.read()
    image_b64 = base64.b64encode(binary_data).decode()

# Data URI example (embed images in HTML/CSS)
data_uri = f"data:image/png;base64,{image_b64}"Copy to clipboardErrorCopied

Data URIs allow embedding binary data directly in HTML/CSS. This reduces the number of HTTP requests and also works offline. But it increases the file size.

For example, here’s an SVG image embedded as a data URI:

<img
  src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAzMiAzMiI+PGNpcmNsZSBjeD0iMTYiIGN5PSIxNiIgcj0iMTUiIGZpbGw9IiMyNTYzZWIiLz48cGF0aCBmaWxsPSIjZmZmIiBkPSJtMTYgNyAyIDcgNyAyLTcgMi0yIDctMi03LTctMiA3LTJaIi8+PC9zdmc+"
/>Copy to clipboardErrorCopied

Base64 is used in many places:

• JSON: Encoding binary data in JSON payloads
• Email: MIME attachments encoding
• Auth: HTTP Basic Authentication headers
• JWT: Encoding tokens in web authentication
• SSL/TLS: PEM certificate format
• SAML: Encoding assertions in SSO
• Git: Encoding binary files in patches

Tools for working with Base64:

• Base64 Decoder/Encoder for online encoding/decoding
• data: URI Generator converts files to Data URIs

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