This is why Linux kernel source code is also signed cryptographically and so is their git repository (all tags are signed). They also employ a PGP-style web of

This is why Linux kernel source code is also signed cryptographically and so is their git repository (all tags are signed). They also employ a PGP-style web of trust instead of an SSL-style centralized certificate management. The chances of someone slipping in a backdoor in kernel releases are very slim.