Z:gnu-www-ja-quick-guide-gplv3--54f8ec-This requirement is limited in/en

This requirement is limited in scope. Distributors are still allowed to use cryptographic keys for any purpose, and they'll only be required to disclose a key if you need it to modify GPLed software on the device they gave you. The GNU Project itself uses GnuPG to prove the integrity of all the software on its FTP site, and measures like that are beneficial to users. GPLv3 does not stop people from using cryptography; we wouldn't want it to. It only stops people from taking away the rights that the license provides you&mdash;whether through patent law, technology, or any other means.