Totally off-topic, but re your binary watermarker I'm looking for a data watermarker. E.g I have an ascii data set (.csv) with say millions of rows and 10 colum

Totally off-topic, but re your binary watermarker I'm looking for a data watermarker. E.g I have an ascii data set (.csv) with say millions of rows and 10 columns. I want to either a) insert occasional "easter egg" records or b) adjust a handful of existing records such that the data is still good, but invisibly, yet provably, marked in some way.