C. Certificate Authority and Certificates
A Certificate Authority (CA), issues a certificate that is used to affirm people’s identity. Certificates are a combination of the users’ identification information and their public keys. Only after successful verification of the user’s identity, the Certificate Authority will be attached to its digital signature. Before the first transaction can be initiated, the user of the certificate has to distribute the public key to other users. The public key from the sender will be compared with the one in the matching certificate.