[MadameMinty]

I remember a protocol which required the text to be replaced with random-length output of a Markov chain text generator, and only then pixelizing.

Oh, you've spent hours on unpixelizing my secrets? Well congratulations, is the last telescope that, nor drink from shrinking nothing out and this and shutting.

[0_____0]

if you fully control the text and layout, you could just replace the redacted text with [redacted]

[MadameMinty]

Yes, but that doesn't potentially waste your opponents' time.

[pfortuny]

Only names are allowed, of long-dead people.