What is the difference between digital signature and digital certificate?

What is the difference between digital certificate and digital signature?

• Answer:

  A digital signature is used to verify a message's authenticity. It is basically an encrypted hash of the message (message digest). The recipient can check if the message was tampered with by hashing the received message and comparing this value with the decrypted signature. To decrypt the signature, the corresponding public key is required. A digital certificate is used to bind public keys to persons or other entities. If there were no certificates, the signature could be easily be forged, as the recipient could not check if the public key belongs to the sender. Thus, digital certificate is used to verify public key's authenticity.