How to facilitate the perception of the uniqueness?

Question

Often my user fill two password fields in a form.

The computation of the two fields generates a unique sha1 (ex: dba59b52c4d483e17cad109e7...).

• I use the generated sha1 to generate something (with some other information).
• I do not display the sha1 to my user.
• If the user completes the form with the same two password, the sha1 is always the same.
• I do not store the sha1 for my user.

To allow my users to discern that the computation of both password is the usual(1) computation, I used the first 6 characters of the sha1 to build a color and I display it to my user.

The user feedback is not very good :

• certain colors are associated with errors or warnings (red, orange, etc)
• I use a limited number of color for color-blind, and often users have identical colors for two different sha1

How to facilitate the perception of the uniqueness of my sha1 ?

If I use pattern or geometric shapes, where should I put it ?

(1) The repetition of filling the form with the same information makes the computation usual.

Answer 1

So I would consider a bar that extends out as the uniqueness of the sha1 increases. So, as the user types their password they notice the bars that extend out from 2-4-6 bars(shown in the image below). This allows the user to understand that the sha1 being entered is increasing in uniqueness. Here the colors don't hold as much as an importance just because of the multiple bars.

If I were to have just one big rectangle(like the one in yours) then you would have to take into consideration the color blind users. But when you break it up into smaller bars that just increase in number as the uniqueness increases, then you would not have to worry too much about the user not being able to differentiate color.

If this method doesn't seem good enough, you could add only text "too short", "medium", "strong", being colored red, orange, green respectively.

Answer 2

You might be better off doing the simplest thing: write "checksum: XXX".

                         ┌──────────────────────────────┐
                         │ ● ● ● ● ● ● ● ● ●            │
                         └──────────────────────────────┘
                         ┌──────────────────────────────┐
                         │ ● ● ● ● ● ● ●                │
                         └──────────────────────────────┘
                                        checksum: 836 ⓘ

I would add some restrictions, though:

• The "checksum" text should not be visible until there is content in a password field, possibly both.

• The checksum should grow as the password grows, capped at 3(-ish) characters. This helps illuminate the purpose of the checksum. I'd cap it at n/2 digits for n characters in the password field.

The advantage of the technical wording is that it sounds like a power-user option. If deemphasized, people are unlikely to pay much attention to it if they're unfamiliar with the term, which prevents it from getting in the way when they're first using the system. After they've recognized it a few times it's likely to be much more obvious that it's like a CVV2 number on credit cards (especially because it's 3 digits).

This is likely to be a bad thing if you're targeting technology-averse users, though.