Base32 decoding is the process of converting a Base32-encoded string back to its original binary data. Base32 encoding uses 32 characters to represent binary data in a textual format, so decoding reverses this process.
How Base32 Decoding Works:
Input Data: You start with a Base32-encoded string that has been padded with = if necessary.
Remove Padding: The padding characters (=) are ignored during decoding.
Map Each Character Back to 5 Bits: Each character in the Base32 string corresponds to a 5-bit chunk. The Base32 alphabet consists of the characters A-Z and 2-7, which represent values from 0 to 31.
Reassemble the 5-Bit Chunks: The decoded 5-bit values are concatenated to form the original binary data.
Reconstruct the Original Data: The resulting binary data is reassembled into its original format (e.g., text or bytes).
Base32 Decoding Example:
Let's go through an example of decoding a Base32 string:
Encoded Base32 string: "NDNFNP"
Remove Padding: In this case, there is no padding, so we continue with the string as is.
Map Base32 characters back to 5-bit values:
N → 01101
D → 00011
N → 01101
F → 00101
N → 01101
P → 10011
Combine the 5-bit chunks:
011010001100101101001101100111011
Group into 8-bit chunks: 01101000 01100101 01101100 01101111
Convert to Characters:
01101000 → "h"
01100101 → "e"
01101100 → "l"
01101111 → "o"
Decoded Output: The decoded string is "hello".
Base32 Decoding Use Cases:
Retrieving Original Data: When you receive a Base32-encoded string and want to get back the original data (e.g., text, files, etc.).
Security and Authentication: In systems like OTP (One-Time Password), the decoded Base32 string may contain keys or tokens that can be used for verification.