Unredacting Pixelated Text

The document discusses signal processing concepts, noting that real-world noise is the RMS sum of multiple time-varying signals and that intersymbol interference can affect (and sometimes improve) channel capacity. It critiques the simplicity of the AWGN model, uses depixelation and the AES ECB-penguin example to illustrate how structure leaks through deterministic transformations, and concludes that deterministic algorithms have inverses and that constrained input spaces make supposed one-way functions susceptible to dictionary attacks.