Now, in the Bitcoin wallet inside Imtoken app, there is the Main Address and then Child Address, different from each other.
Can anyone who knows the difference please elucidate on this? How are they related please?
Looking at the "Imtoken" specific case... Their definition of "Main Address" and "Child Address" is simply what ETF stated earlier...
looks like Main address is the first bitcoin address that created with xPub and Child address is the 2nd/later bitcoin address created with xPub which isn't used yet.
That is to say that:
"Main Address" = m/44'/0'/0'/0/0
"Child Address" = m/44'/0'/0'/0/1, m/44'/0'/0'/0/2... m/44'/0'/0'/0/n
I guess they have done this so that users will think they have a "fixed" address. I have seen a lot of newbies get confused when an HD wallet starts spitting out new receive addresses and get concerned that they're going to lose coins.
This Main/Child address system that Imtoken have created looks like an attempt to try and ease these concerns by pretending that you have both a (fixed) "main" address... but can also generate multiple unique addresses if you want.
The main address as ETF said is the address that is used for recieving and the child address is the change address (nothing to do with master keys)
No... it isn't "receive" and "change"... they're all "receive" addresses... the screen shows xpub
0/0 and xpub
0/1...