On Tue, 30 Dec 2003, Bill Stewart wrote:
The reason it's partly a cryptographic problem is forgeries. Once everybody starts whitelisting, spammers are going to start forging headers to pretend to come from big mailing lists and popular machines and authors, so now you'll not only need to whitelist Dave Farber or Declan McCullough if you read their lists, or Bob Hettinga if you're Tim (:-), you'll need to verify the signature so that you can discard the forgeries that pretend to be from them.
You'll also see spammers increasingly _joining_ large mailing lists, so that they can get around members-only features.
This has already happened: Krazy Kevin pulled this stunt 5 years ago on at least one list I was on, joining the list to harvest the most common posters, then spamming using them as sender envelopes after he'd been kicked off.
At least one large mailing list farm on which I've joined a list used a Turing-test GIF to make automated list joining difficult,
...discrimination against blind users - this is legally actionable in several countries. There is a blind group in the UK taking action against a number of companies for this and the Australian Olympic committee ended up being fined several million AU$ for the same offence in 1999.
and Yahoo limits the number of Yahoogroups you can join in a day, but that's the kind of job which you hire groups of Indians or other English-speaking third-world-wagers to do for you.
To underscore that point, I've _watched_ cybercafes full of SE asians(*) doing exactly this kind of thing for the princely sum of US$5/day - twice the average wage of the area, even after the cafe fees were deducted. (*) Philippines and east Malaysia. AB --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo@metzdowd.com