Hi linux-crypto, Working on hacking together a tcpcrypt implementation which needs to use KPP/ECDH based on new temporary keys for each new connections which uses encryption. Sadly, the KPP API seems to be very much targeted at long-term keys (likely cause most of the crypto API is used that way - bring up an instance of AES for your drive encryption and keep it around with the same key forever), and gets rather inefficient if you want to use it with short-term keys.
eg if you were to implement tcpcrypt with the current API, you're going to call crypto_alloc_kpp (and, thus, do a locked scan of crypto_alg_list, a module_get, etc) on every new TCP connection that successfully negotiates encryption, only to free it in a packet or two when you've negotiated session keys, and probably keep around an extra one always to create a module dependency (or am I missing how something works, there?). Since I mostly don't know what I'm doing, I figured I should ask what people think about tweaking the API somewhat: (0) I missed something obvious about the API (or some other part of linux-crypto) and should be using it in a much smarter way. (1) add some new kpp-like API that lets you get a crypto_alg which doesn't store its own private key but lets you do DH with a provided private key in the request? (2) Tweak the KPP API to look more like the above (it has rather few users in-tree at the moment). (3) Do some dirty higher-level hack like keeping a pool of crypto_kpps. I'm happy to work on a patch to do any of the above :). Thanks, Matt
