Candidate Block

      Within the world of blockchain & cryptocurreny, progression of a network is measure by blocks rather than by time. Blocks are sequenced according to their preceding blocks and their proposing miners. Whenever a block is appended to the chain, there must be an incoming block that is being created; that is known as a “candidate block”.

     While the incoming block is being mined and is put up as the candidate for the next block it is possible that at the moment of appending a different block is selected.

     These are extremely rare cases but they do happen; some of the reasons as to why a candidate block might denied/replaced are as follows:
   – False information in the block (miner inserts fake block)
   – Network latency delays the block proposer and in order to proceed normally it quickly selects another valid block.
   – Malicious actor gets away with a micro 51% attack and substitutes the block.