Method and system for carrying out secure signing of a person on a data packet sent from a sender to a recipient, the sender and the recipient connected to a data network via network connection means. A biometric sample of the person is sampled and converted to a digital form. A first digital seal produced from the combination of the digital data packet and the biometric sample, or from two or more digital seals derived from the digital data packet and the biometric sample. The digital data packet and the biometric sample and the digital seal are sent to the recipient. A second digital seal is produced from the combinations of received digital data packet and the received biometric sample. The first and the second seals are compared and if the first and the second seals are identical, the authentication of the digital signature is approved. Otherwise, the authentication of the digital signature is denied.