Recovering blurred text in Bishop Fox's Unredacter challenge

Bishop Fox hosted a CTF-style challenge related to their article Never, Ever, Ever Use Pixelation for Redacting Text. That article and its Unredacter tool grew out of an earlier puzzle: JUMPSEC Labs had tested the Depix tool on pixelated text with mixed results and dared readers to crack a harder image, which Bishop Fox’s Dan Petro then did. The challenge winner, Shawn Asmus, published his write-up for the challenge. His target turned out to be blurred rather than pixelated, so Unredacter was of little help and he fell back on font matching, GIMP sharpening, Richardson-Lucy deconvolution and some OSINT. This is a good reminder to properly redact documents. Looking back, there are many examples of pixelations, swirl and black-boxes gone wrong.