A transaction signature refers to the digital information used in cryptocurrency transactions to verify the identity of its participants. Through advanced cryptography, transaction signatures are formed from a combination of public and private keys. Every transaction is assigned a unique transaction signature to ensure that once a signature is already used to verify a particular transaction, there won’t be any duplicates.
A blockchain requires a signature from the sender to confirm that he is, in fact, the one sending before all transactions are broadcasted to the chain. Transaction signatures are also designed to keep the confidentiality of one’s private keys whenever it makes on-chain transactions.