Bulletproofs are short Proofs for Confidential Transactions. As solution privacy in the blockchain, Dr. Maxwell proposed the use of Confidential Transactions, which hide amounts with the use of Pedersen Commitments. To verify that amounts are correct, range proofs are used to ensure that the sum of transaction inputs is greater than the sum of transaction outputs and that the amounts are not negative.
However, this is costly in terms of storage space, as range proofs need to be attached to every transaction.
Bulletproofs are short, non-interactive, zero-knowledge proofs that require no trusted setup. They are designed to enable efficient confidential transactions in Bitcoin and other cryptocurrencies.