What Are the Key Technical Requirements for a Blockchain to Implement AuxPoW?

The key technical requirements for a blockchain to implement AuxPoW include using the same hashing algorithm as the primary chain, as the hash generated must satisfy the difficulty of both chains. The secondary chain's block header must be structured to be easily included in the primary chain's block.

Crucially, the primary chain's protocol must be compatible and allow the inclusion of the secondary chain's proof of work, which is not always the case without a hard fork. The secondary chain also needs a mechanism to verify the primary chain's proof of work.