A very useful device for people who can not trust the host they are talking to such as users of multiuser unix systems, or low security BBS systems, or "public access" workstations or PC-s, (this includes almost every single person that uses e-mail, except probably for users of a high-security mainframe communications system) would be an RS232 crypto "dongle" that would sit between the terminal (or modem) and the remote system. It would contain some tamperproof (write and decrypt only, can not be read out without a great deal of trouble) memory (as someone at the midnight crypto session at Hackers was talking about) for storage of the private key, some nonvolatile memory (flash eprom?) for the public key ring, and a processor to do the encryption/decryption. It would look (if all that can be fit into a small enough space) like a null modem or a gender changer. (or an RS232 break-out box). If crypto tech ever becomes illegal, it could even be disguised as one, with some special signal combination enabling the crypto function. It should also contain some out-of-band signal such as an LED to indicate that it is actually doing the decryption, instead of the host mimicking it. If introduced now or in near future, this device could become incredibly widespread, since most everybody that is accessing any form of e-mail goes at some point through an RS-232 link (either a terminal hanging off a terminal server, or a PC connected to a modem). Also, it would not require ANY special software on the host or the pc, nor any special terminal. Thus it would work with any of the great variety of e-mail and BBS sysetems that exist, instead of having to deal with each of them individually as a purely software-based approach would have to. It would also be completely independent of the type of computer/terminal or operating system used. You would send the usual mail command to the host, type the magic sequence to the encryption device (or even better, flip a little switch), and then type your message. The device would send to the host the ciphertext, while echoing the plaintext to your terminal so you can see what you are typing. The plaintext would never travel further than the RS232 connection between your terminal and the encryption device. When you receive an encrypted message, flip the switch on your device to "decrypt", and tell the host to send you the message. The host and any intervening networks would only see the ciphertext. The only place the decrypted text appears is on your terminal. I think this is as secure as you can get (until a decryption implant can be put in your head :-). Now, to allow the use of existing tools (pagers, editors, mailers, etc) the device should be completely transparent except when performing the crypto function. Even then, careful design should make it pretty transparent. For example if it passed all control characters intact, it could be used with a text editor that uses control key sequences for movement. It could be programmed for most common arrow key sequences, and for commands for editors such as EMACS, vi, etc, to pass them through unchanged. Same thing for receiving. When decrypting, it should pass through unchanged any characters passing through the other way, and should not interfere with terminal control characters, so any mail viewing program would not be affected. Additional functions it might include are generation and verification of signatures, an echo mode with decrypt/encrypt (so you could store the encrypted texts on your local drive, and to view would just "ascii upload" them to the device while in a comm program; also you could prepare the text of a message locally, while storing the encrypted text echoed back. Then you could upload the cyphertext to the system), a simple local editor and viewer, and anything else we have the ROM space for. Once the basic hardware is developed, there is nothing to stop one from including any desired features. Is anyone here already working on something like this? If not, is anyone interested in working with me on developing this kind of a device? I have the design pretty much thought out (this post is just a summary). I also have a clear picture of the prototyping and development process, and am capable of writing the software part. I would like to work with a partner who knows the hardware part of all this. I.E. the RS232/UART control, PCB layouts, that kind of stuff. Also, I know almost nothing about the technology of tamperproof memory storage. The main objective of this is not to make loads of money (though that would not hurt either) but to increase widespread accessibility and use of good crypto technology. So I would make the schematics and code available, in case anyone wants to be SURE and build one themselves. This could probably also be made available in kit form, that could be assembled by the user. (an interesting parrallel: this is how the personal computer was first distributed... look at the prevalence of PC use today!) This way they can be more sure that it does what it says it does. So, if you have read this far you are probably interested in this. PLEASE reply to me or to the list. If you are the person I am looking for to help with the development, please contact me soon, using one of the addresses or numbers listed in the signature. If you think you would be interested in buying or using such a device when it is ready, please let me know. If you have any improvements to the idea, or other comments, or reasons why you think this device would not be useful or could not work, please let me know too. Waiting for your feedback.... -- Yanek Martinson mthvax.cs.miami.edu!safe0!yanek uunet!medexam!yanek this address preferred -->> yanek@novavax.nova.edu <<-- this address preferred Phone (305) 765-6300 daytime FAX: (305) 765-6708 1321 N 65 Way/Hollywood (305) 963-1931 evenings (305) 981-9812 Florida, 33024-5819