| For FOSS, signing code gives you the benefits of time shifting and the benefits
of a web of trust. Getting the public key at the same time and from the same
place as you get the code gains you almost nothing because if the code is
compromised then the public key could just as easily be
compromised.
Ideally, every code creator and every distribution would have
their own signing key(s). These would change much less frequently than the code
itself. Once you have a key from RedHat and you know that key is valid then you
can be sure the code you are getting from RedHat is the code they signed.
RedHat, in turn, can be sure it is getting source code signed by the
creators.
Once a system like this is in place then infecting a server with
malicious versions of code has a much lower chance of infecting downstream
systems. The only systems that would be vulnerable would be those that are
downloading code and at the same time downloading the public key for the first
time. Everyone else will have a cached copy of the public key that does not
match the signed code. They can immediately raise the alarm saying the code has
been compromised. Even worse for the potential attacker, everyone else can
still download the public key and raise the alarm when it does not match the
copy of the public key they have stored locally.
I don't see where a
central authority would add value to this model except possibly for first time
users. But that role is much better served by a web of trust where everyone is
vouching for each other. A central authority is a single point of failure and
thus an obvious target for attack. A web of trust is more difficult to
compromise because attackers would need to gain control of a bunch of systems
nearly simultaneously. Even then, if people downstream are caching and
verifying public keys, a coordinated attack would be recognized almost
instantly.
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Our job is to remind ourselves that there are more
contexts
than the one we’re in now — the one that we think is reality.
-- Alan Kay [ Reply to This | Parent | # ]
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