Skip to content

Decode Base64 and XOR

Reverse a common two-layer obfuscation pattern with an explicit XOR key.

Install in Serialize

What it can do

  • Remove a Base64 wrapper
  • Apply a repeating UTF-8 XOR key
  • Recover the original bytes

How the recipe works

From Base64

Decode the printable transport form.

XOR

XOR the bytes with the repeating key KEY.

Demonstration

Sample input

GCArIiQ1Ij88ayE8Jio=

Expected result

Serialize demo

When to use it

  • Reverse-engineering exercises
  • CTF puzzles
  • Understanding reversible obfuscation

Adapt it

Change the key representation to Hex when an analyst supplies byte values rather than text.

Source and verification

Adapted from SANS Internet Storm Center: Base64/XOR recipe. The explanation and sample are written for Serialize, use synthetic or documentation-safe data, and are checked against the current operation catalogue. The workflow runs locally without an external API call.

Navigation

Type to search…

↑↓ navigate↵ selectEsc close