-- 177 At 5:00 PM -0800 12/4/97, James A. Donald wrote:
I have produced a program that, like PGP, provides digital signatures and communications encryption. http://www.jim.com/jamesd/Kong/Kong.htm This is the first beta. Please beta test this product.
At 07:06 PM 12/12/97 -0800, Bill Stewart wrote:
The web page says that the first beta had some problems,
Beta 2 is now out. Please uninstall your old copy, using "Add/Remove programs" in the control panel, before installing the new copy, as overinstall does not work. (If you forgetfully overinstall, a warning comes up, but most people cheerfully disregard the warning)
- Signed Message: Delimiter, Message Body, ECC Public Key, ECC Sig. I didn't notice what hash was used for the signatures -- SHA?
SHA: I failed to document that, will add it to the documentation.
- Encrypted Message: ECC(SessionKey), RC4(Message Body, SessionKey).
I'm not sure if there are headers that include the recipient's key, or if there's any special form for an encrypted-and-signed message. I assume there's no multiple-recipient form?
Multiple recipient form works, but the user interface to use it does not yet exist which makes it kind of useless. Coming soon.
1) Are the Signer's Name and the ECC key included in the material that's hashed for signature? Doing that is valuable, but depending on it makes it more difficult if people change addresses.
Yes: However the name is only hashed in a cryptographically weak manner, so a third party could change the name in a cleartext message. However if the message is cleartext there is nothing to stop him from copying the body and giving it any signature he pleases, so this does not actually gain the attacker anything. After all, that is what cleartext is. If he changes the name it looks to the user and Kong like a new and different signature.
2) It would be nice if the starting and ending delimiters were different. This would let you nest messages without needing >s. Can Kong tell a nested opening -- from a closing --digsig ? Are --s escaped, or at least <NL>--digsig?
-- Yes: For example this message contains a nested message. --digsig James A. Donald 6YeGpsZR+nOTh/cGwvITnSR3TdzclVpR0+pr3YYQdkG J14rDU1EjUofOmSoHg1Ye0GF6/+6wdvxmCwMryE4 1jNcIP5kRfVPada+5w8zfIGEodi2Mrz80ZbvXsK1
3) How are newlines and whitespace in the message body handled for signatures? Canonicalized? Ignored? Not worried about?
Not worried about, which is probably a seriously bad idea. Will fix in a later release. In a later release I will canonicalise carriage returns to Microsoft conventions, but not whitespace. As this is alas, a Borg only product, and will remain so for some time, such canonicalisation will not break existing signed documents.
This affects not only reliability of signatures after emailing, but also affects signing binary files.
Signing binary files is not yet supported, and will not be for some time.
4) I'd guess, since you're using 240-bit ECC and base-64 encoding, that the first 40 characters of garble in the signature are the key, and the remaining 80 characters are the signature itself?
Yes
If so, is there some easy way to use the 40-char string, e.g. type in a copy from the bottom of a business card?
Yes If Kong says a signature is good, and the public key agrees with a business card then the guy who wrote the business card is claiming to be the author of the message. Actually you do not have to check all 43 characters. It is sufficient to check the first ten characters, or any ten characters.
Some of the documentation says something about the key being derived from your passphrase and a randomness file hashed together. How does this affect multiple keys generated by the same user? I assume it means you can't share passphrases between keys.
If two keys have the same passphrase, but a different secret file, then they will be two completely different keys. However, the same passphrase, and the same file, means the same key. The secret file is merely concatenated with the secret file
5) Is the format of the signature freeform, or do the newlines and whitespace have to be in their official locations?
Minor flexibility. You can add or remove leading blanks, and use either lf or cr or both. It is not totally rigid, but it is pretty rigid. --digsig James A. Donald 6YeGpsZR+nOTh/cGwvITnSR3TdzclVpR0+pr3YYQdkG Uy36NbrQf/3FKV77cTtzFrHxsy0dcx9l6Svy/Fl5 xP+I6vLpjTgacrHEqXoD3gv+HF9Tx4Zl+0yDGhQF