In the context of Bitcoin, cryptography is the use of mathematics to secure information. Cryptography is used to create and secure wallets, sign transactions, and verify the blockchain.Cryptography is the branch of mathematics that lets us create mathematical proofs that provide high levels of security. Online commerce and banking already uses cryptography. In the case of Bitcoin, cryptography is used to make it impossible for anybody to spend funds from another user's wallet or to corrupt the block chain. It can also be used to encrypt a wallet, so that it cannot be used without a password.