On 2011-11-04, Robert Ransom rransom.8774@gmail.com wrote:
On 2011-11-04, George Kadianakis desnacked@gmail.com wrote:
To avoid problems associated with the human condition, schemes based on public key cryptography and certificates can be used. A public and well tested protocol that can be used as the basis of a future authorization scheme is the SSH "publickey" authorization protocol.
Secret keys for DSA (with a fixed group) and EC-based signature schemes can be short enough to be fairly easy to transport. Secret keys for RSA are a PITA to transport, unless you either (a) specify a deterministic key-generation procedure, or (b) make the public key available to all clients somehow, and provide enough information to clients intended to access a bridge that the client can factor the modulus efficiently.
Um. On second thought, this is just freaking ridiculous (especially my paragraph). We don't want each client to have to generate a public-key authentication keypair and send its public key to the bridge in advance; that would be a nightmare to implement with our current bridge infrastructure.
So the only sensible ways to use public-key authentication seems to be to give the same secret key to every authorized client (i.e. distribute it like a password) (see Telex), and then we might as well use a (shorter) shared-secret password (unless we need magic features of a specific cryptosystem like the ‘public-key steganography’ used in Telex).
Robert Ransom