The private key is known only to the owner, while the public key can be distributed publicly. If the message is encrypted using the public key, then only the private key will be able to unencrypt it. The reverse is also true if the message is encrypted with the private key. Certification The final element in digital signatures is certification. Certification involves the existence of a trusted third party, generally called a certificate authority, who confirms the identity of the signer.
Certificates are similar to many other forms of personal identification.
For example, a driver's license issued by the DMV is often required to prove one's identity when writing a check. Similarly, a digital certificate can be used to prove one's identity when sending a digitally signed document. Back to the Top . . In additon to the above format, other types of digital signature technology exist. These other types are known as biometric technologies because they try to mirror the physical act of signing a document.