The invention provides a method for providing a strong link between a Subject and a cryptographic public/private key pair. The proposed Subject device and key distribution algorithm is less prone to man-in-the middle attacks as comparable known algorithms, thereby inherently strengthening the trustworthiness of any digital signature made with a private key distributed to a user in accordance with the proposed method. The invention additionally enables distribution of authentication factors over unsecure channels and reducing the need of sensitive information transmission by at the same time augmenting security for finally associating a generated public/private key pair to a Subject and using it for signature creation purposes.