One question still remains, however. Successfully using a public key to decrypt a document or file proves that it was created by the entity possessing the corresponding private key. But, how can the recipient be sure of that entity's identity? For example, how can a consumer know that a fire purportedly crested by a financial institution really was created by that financial institution and not by someone who created a pair of public and private keys and uses them to masquerade would not provide any protection against impersonation. The answers to these questions involve the use of digital certificates and the creation of a public key infrastructure.