What is the normal lifetime of a certificate? What happens when a certificate expires?

Generally, SIGNiX-generated end-user certificates expire after two years. SIGNiX customizes the expiration dates of certificates to meet the needs of our customers.

The risk for a key to be compromised increases over time, Certification Authorities place a limit on the lifetime of each private key. The normal lifetime of a private key is determined by the validity period of the corresponding certificate. Signature verifiers will not verify digital signatures created after expiration of the associated certificate.