Module shadow 

A reversible XOR keystream layer — obfuscation, NOT encryption.

⚠️ This is not secure and must not be used for confidentiality. It XORs the payload with a keystream derived from a u64 key. That hides bytes from a casual glance and is exactly reversible, but a static-key XOR stream is trivially broken: any known plaintext recovers the keystream, two messages under one key XOR to reveal each other, and there is no authentication of the result. For real confidentiality use a vetted authenticated-encryption (AEAD) construction. This layer exists to demonstrate the honest limit of XOR: a reversible, unsafe-free transform that noha can hold at 100% mutation coverage — which proves it is correct and reversible, NOT that it is secret.

mask is its own inverse: masking twice with the same key returns the input.

Enums

ObfuscateError

What can go wrong.

Functions

mask

XOR data with the keystream for key, writing to out; returns the length (always data.len()). Reversible: mask(mask(x, k), k) == x. Obfuscation only — see the module docs; this provides no real confidentiality.