[Semiapies]

So, this system, if it ever got wide use, would rely on users remembering which "unique" colors were randomly assigned to them by whichever sites they use.

I was thinking, "Gee, if a scanner put a random color bar at the top of the phishing emails, how often would the color look close enough that the user couldn't distinguish between it and their own color, at least without comparing the colors side-by-side?", but I'm not convinced users would even remember their colors after the second or third one.

(And if course, this is very flawed for the color-blind and utterly useless for anyone using screen-readers.)

[emeltzz]

I think this is a good start--some easy modifications could turn it into a 3-color banner similar to the french or mexican flags, which would be both easier to remember and less likely for a scammer to guess correctly. Or you could do randomly generated animals! i.e. "if you don't see a pink bear, you're being phished"