Server for issuing a digital certificate and device for verifying authentication

A method for a Certification Authority (CA) server for issuing digital certificates, the method comprising:

• generating a first digital certificate for a device, wherein the first digital certificate is associated with a first public key of the device,
• calculating an update factor for a first private key of the device,
• calculating a second public key for a determined time period for the device, based on the first public key, the calculated update factor, and a predefined public system parameter, and
• generating a second digital certificate valid at the determined time period and associated with the second public key and send the second digital certificate to the device.

A device comprising:

• one or more processors;
• and
• a computer memory communicatively coupled to the one or more processors and having executable program code stored thereon, wherein the one or more processors are configured to:
• store a pair of a first public key and a first private key,
• store a first digital certificate issued by a Certification Authority (CA) server, wherein the first digital certificate is associated with the first public key,
• calculate an update factor for the first private key,
• calculate a second private key based on the calculated update factor and the first private key,
• receive a second digital certificate from the CA server, wherein the second digital certificate is associated with a second public key, and
• verify an authentication of the device based on the second digital certificate using the second public key and the second private key.