Base64 Encoder/Decoder

About Base64 Encoding

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. It is designed to carry data stored in binary formats across channels that only reliably support text content.

How Base64 Encoding Works

Base64 encoding follows these steps:

  1. The input data is split into groups of 3 bytes (24 bits).
  2. Each 24-bit group is split into four 6-bit chunks.
  3. Each 6-bit chunk (values 0-63) is mapped to a character in the Base64 alphabet.
  4. If the last group has fewer than 3 bytes, padding '=' characters are added.

Base64 Character Sets

There are two common Base64 character sets:

  • Standard Base64: Uses A-Z, a-z, 0-9, +, and / with = as padding
  • URL-safe Base64: Similar to standard but uses - and _ instead of + and /

Common Use Cases

  • Encoding binary data in emails (MIME)
  • Embedding image data in CSS or HTML
  • Storing complex data in URLs
  • Transmitting binary data in XML/JSON

Technical Details

The encoding process in detail:

Text:      H     e     l     l     o
ASCII:    72    101   108   108   111
Bits:     001001000110010101101100011011000110111100
Groups:   001001 000110 010101 101100 011011 000110 111100
Decimal:  9      6      21     44     27     6      60
Base64:   J      G      V      s      b      G      8