A CA is an organization that creates digital certificates for individuals and Web servers, after verifying the identity of those persons or sites. A CA signs each digital certificate with its own digital signature, thus vouching for the identity and trustworthiness of the owners of the certificates.
One of several safeguards for secure e-commerce and overall data transfer, a certificate authority is a third-party organization that creates digital certificates for a public key infrastructure (PKI). The certificate authority guarantees a user's identity and issues public and private "keys" for message encryption and decryption (coding and decoding). Essentially, the certificate authority guarantees that a user is the person he or she claims to be, and conversely, that the provider of the information is who the user believes he or she is accessing.
A trusted third-party organization or company that issues digital certificates used to create digital signatures and public-private key pairs. The CA guarantees that the individual granted the unique certificate is who she or he claims to be.