On 1/1/06, J.A. Terranson <measl@mfn.org> wrote:
(1) We are describing encryptedmessage sent over the public internet - granted, it's in "pieces", yet it's still sent into the public cloud;
yeah, follow tcp stream in ethereal is a good example of how trivial it is to recreate a session of communication given an archive of its component datagrams.
(2) These various pieces are all "record" communications as far as NSA/Echelon is concerned, and therefore we should expect that they will draw significant attention - and end up in permanent archives;
right. hence my fetish for one time pads for key exchange and previous comment about quantum computers / fast GNFS / etc. they are up to 8 qubits, only a few thousand more to go. ;)
(3) Since all off the pieces have been stored - including both the encrypted messagetexts and the decryptors, what is to prevent a time-faking attack against this message? After all, if you have all the parts, you can just "reinstantiate" the network as it was was the messages were originally sent.
this is particular to the method TD mentioned i think... i am assuming the following: - the operating system is installed on a loop-aes volume so that integrity of the kernel, libraries and utilities is protected via passphrase. - the one time pads are stored encrypted in a similar manner so that access to them requires external keys (like the gpg encrypted keys used for loop-aes volumes) - the passphrase used to authenticate a user for access to the pads is coupled with external storage (usb) of the keys used to access the pads. to recover the plaintext communication from the encrypted datagrams the attacker would need to obtain the encrypted pad, the keys on external storage (usb), and the passphrase to access the keys.
(4) For any form of time-destruction messaging to really work, the keying information would have to be tied to a physical <something> that cannot be reclaimed, and which decays at a fixed, known, and closely approximatable rate (a radiodecay probably doesn't meet this criteria);
Every time-sensitive auto-destructing system Ive seen discussed here fails these weaknesses.
this doesn't provide time destruction so i assume this is in reference to Tyler's description. you could couple the user authentication with a physically hardened token of some sort for access to the pads but even this would require manual destruction. do they make physically hardened authentication tokens with timed self destruction built in?