Topic: Initial Draft - ARETF-APRS-Authentication

I am happy to announce the first standards draft for the ARETF. Andrew-KA2DDO was nice enough to write up a method for authenticating APRS packets using Hashed Message Authentication Code (HMAC) digests.

I have created a git repository at GitHub for ARETF documents.( Here is a direct link to the document. ( … cation.txt) I still need to work out how to manage permissions to commit to the documents, but we can start started discussing things.

Big thank you to Andrew for getting the ball rolling.

Kenny, KU7M

Kenny, KU7M

Re: Initial Draft - ARETF-APRS-Authentication

First, thank you to Andrew KA2DDO for the first draft.

Some comments:
- Key management: would it not be better to use a signature algorithm that uses asymmetric keys, to avoid the key distribution problem with symmetric keys. Or this meant to be used solely by a group of stations sharing a symmetric key, rather than a general, public, authentication scheme. I know it is a tough problem, because asymmetric algorithms need much longer keys to be secure, so it calls for innovative thinking, with respect to how much assurance you want. If you can live with 99.999999976% rather than 100% assurance of authentication, then a CRC-32 of an RSA signature with any key length (1024, 2048, 4096) would accomplish much the same, without the sharing of keys. Of course, this opens a whole discussion on public key dissemination.
-I am confused by this: " The body ending with the literal characters "\S" (hexadecimal bytes  5C and 53) followed by 4 to 20 non-blank printable characters that ASCII-85 decode into a valid 16-byte value". Should it not be exactly 20 non-blank printable characters rather than 4 to 20?

Again, thank you