How to Decode a Base64 String Pre-Processed with XOR Encryption?

Decoding a Base64 Encoded String

The provided Base64 encoded string underwent a transformation before encoding. To decode it back to its original form, we need to undo the initial transformation and then perform the Base64 decoding.

Decoding

1. Reverse Exclusive OR (XOR) Transformation:

   • The string was initially processed using an XOR operation with a known string "_p0lizei."
   • To reverse this transformation, we need to perform an XOR operation between the decoded Base64 string and "_p0lizei." This can be done using a bitwise XOR operator (^) in a programming language.

2. Base64 Decoding:

   • Once the XOR transformation is reversed, we have the original string back in its binary form.
   • To obtain the actual string value, we need to decode the binary string from Base64 using the Convert.FromBase64String(encodedString) function in a programming language.

3. UTF-8 Encoding:

   • Finally, the decoded binary string needs to be converted back to a string using the UTF-8 character encoding using the System.Text.Encoding.UTF8.GetString(data) function.

By following these steps in reverse order, you can decode the provided Base64 string back to its original plaintext form.

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