The Black Hand Insignia

For the Hand-scan:

The Black Hand scanner reads living tissue, as it is in most cases it takes a tissue sample from the one wishing to use it. the sample is then read and if recognized allows access to the user.

For the Bowl:

ever hear the phrase "I put my blood, sweat, and tears into that" well, that's taken quite literally for the Bowl.
The Bowl requires you to put an ounce of blood, some sweat, and tears into it, where the contents are analyzed and if accepted allowed access to whatever it was blocking, if rejected it'll keep asking for more.

For the Eye:

it's an eye-scan. guess.

For Blind Faith:
( it looks like a hole in the wall )
You put your arm in, it likes you: you keep it, it doesn't you don't.
not really, it scans your arm, reading your bones and tissues to make sure you can enter whatever it's blocking. but you will lose your arm if your rejected. Because the Black hand don't like thieves or hackers they don't control. the scan is nearly instantaneous, so don't get any bright ideas.

For the Sacrifice:

Hope you brought someone you don't like..... just kidding, that would be incredibly problematic, so the idea was never put into use, because that mean cleaning up the bodies etc. and thats too much damn work.