In several episodes of The Mandalorian we have had mention to a chain code. I believe Cara Dune, Moff Gideon, Greef Karga, and Din Djarin all bring them up at some point.
In Chapter 14: The Tragedy chain codes are again brought up, this time by Boba Fett as a means to prove his armor is actually his.
[Boba Fett] I want you to take a look at something. My chain code has been encoded in this armor for 25 years. This is me Boba Fett. This is my father Jango Fett.
[Din Djarin] Your father was a foundling?
[Boba] Yes. He even fought in the Mandalorian Civil Wars.
[Din] Then that armor belongs to you.
In the above exchange, lines of holographic text appear from the forearm piece of armor.
Din seems to be able to read it (makes sense reading is simple) and deduce the information. But how does Din know that chain code relates to physical person person standing in front of him? If it is just some alphanumeric code anyone could claim a code is theirs.
However, the way Cara Dune brings it up (IIRC) is that she can't show her face in the New Republic as her chain code is linked to crimes or whatnot. Are all citizens of the galaxy required to have a way to identify themselves via their chain code upon request and that the person showing it can only show their own code?
Here on Earth we have fake ID's that can be used to claim we are someone we are not or be (typically) older than we are. People accept fake ID's because there is a picture and identifying information also on the card. A chain code seems more like a social security number, just a name and number, and so anyone could present the name and number as their own. Does a chain code have identifying information in it, i.e. certain letters or numbers correspond to a physical trait?
So what exactly is a chain code and how does it work?