There is a significant legal distinction between qualified signatures and standard or advanced signatures. Qualified electronic signatures have carefully defined regulatory limits in terms of how the signer's identity is validated and the signature key is protected. It has the same legal impact as a handwritten signature, but the other levels of electronic signature are more probative.
When the gadget is qualified, it will have previously been verified and confirmed by the Information Commissioner's Office. A single key can frequently be used for up to three years.
The qualified signature technique follows the same security guidelines as the advanced signature procedure, but it requires that the signer's identity be verified beforehand and that the signature key be stored in a qualified electronic signature creation device (QSCD). The signer is handed a "token" (smart card, USB key, badge) that allows the certifying authority to validate their identity before signing their documents after entering a personal PIN. This cryptographic key must be exceedingly secure and trustworthy; thus, it must be kept in a secure location.