Block signing is used so that a new block can be added to the chain (blockchain) after the information has been verified. Thus, a block with information is created in the blockchain, and users, according to a consensus algorithm, verify that the transactions are correct: they analyze and then confirm that the sender’s wallet has coins to transfer.
The block is then finally signed and added to the chain. The blockchain is automatically updated, and new transactions are executed on the computers of other participants.
The signature is a number obtained by hashing a random infinitely long number. For it to be recognized by all participants in the chain, it must be signed by someone who is already in the chain. Thus, block chains are applicable only when absolutely all the digital signatures in it can be validated.