On 29 May 2012 01:35, Peter Gutmann <pgut...@cs.auckland.ac.nz> wrote:
> Peter Maxwell <pe...@allicient.co.uk> writes: > > >Why on earth would you need to spread your private-key across any number > of > >less secure machines? > > The technical details are long and tedious (a pile of machines that need to > talk via SSH because telnet and FTP were turned off/firewalled years ago, I > won't bore you with the details). The important point isn't the technical > details but the magical thinking, "a private key sprayed all over the > place in > plaintext is more secure than a line-noise password because everyone knows > passwords are insecure and PKCs are secure" (and, as I've said, this isn't > an > isolated case). > To make an analogy: people still manage to kill themselves in cars fitted with seat-belts and airbags. That does not imply those measures are not an improvement but rather that the improvement is a statistical one. Similarly, just because some numpty stores private keys in plaintext does not imply that public key auth is not in general an improvement over password auth. Yes, it is not magical but if the users of such systems cannot handle private keys with at least minimal care, there are bigger problems afoot. If multiple users need to use SSH on multiple hosts, they should store the private key on removable media and use it from a limited number of hosts; to "hop" from one host to another, create a port-forward on the first ssh session form which the second ssh session can connect through to the destination host, hence obviating the requirement for copying private keys and ensuring the intermediate hosts cannot decrypt any traffic. I have yet to encounter a problem in real life that requires private ssh keys to be copied all over the shop and when it happens, it's bad management, which no technical measure is going to sort.
_______________________________________________ cryptography mailing list cryptography@randombit.net http://lists.randombit.net/mailman/listinfo/cryptography
