pub fn kid_from_thumbprint(thumbprint: &[u8; 32]) -> [u8; 8]Expand description
The kid for a thumbprint: its first KID_LEN bytes. The birthday
bound is about 2³² keys, and a resolver returns several candidates on a
collision (§3), so the full thumbprint, not the kid, is what names a
key unambiguously (Opened::key_thumbprint).