Password entry can be frustrating, especially with long or difficult passwords. On a webpage, secure fields obscure user input with •'s, so others are not able to read it. Unfortunately, neither can the user, who cannot tell if she got her password right until she clicks "Log In". Chroma-Hash displays a series of small colored bars at the end of field inputs so you can instantly see if your password is right.
Chroma-Hash takes an MD5 hash of the input and uses that to compute the colors in the visualization. The MD5 hash is non-reversible, so in principle no-one could know the password from just reading the colors. The same password will display the same sequence each time. So, for instance, one can learn to expect "blue, red, pink"; when other colors appear, the password has been repeated wrongly.