Altering block information

Question

We have two node and both nodes have copy of blockchain (multichain). We want to create a cenarios where third node modifies block information on node two.  We have following questions.

1. Does multichain detect that information is tampered?

2. As a user of the blockchain how is the tampering is made known to the node two?

3. Is there a API to modify block information by node three?

It would help if you share these information.

Answer 1

In general it is not possible for node three on its own to modify block information on node two, unless node three has mining privileges and enough weight to cause node two to switch to a different fork from the one it's currently on. Blockchains don't allow nodes to directly modify each other's states.