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0 pointswhit53713y ago0 comments

Thank you, good info. For privacy reasons, we've been hoping to not track IP addresses:

https://github.com/whit537/www.gittip.com/issues/345

Even then, I'm not sure I would trust this approach. I feel much more comfortable white-listing accounts, and for the time being that's not too onerous.

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4 comments · 2 top-level

rmc13y ago· 2 in thread

For privacy reasons, we've been hoping to not track IP addresses

You could hash the IP address, with some suitable salt. Then compare against that.

The purpose of storing IP addresses isn't to find out "the IP address of the user submitting the form", but instead to answer "How many other credit card numbers have come from this address?", something that can be done with sha512("salt_mc_salty_$IP")

whit537OP13y ago

Good call. I've made a ticket for this, "roll our own automatic fraud prevention," and have included this suggestion: https://github.com/whit537/www.gittip.com/issues/360

schiffern13y ago

The only problem here is, IP addresses are such a small space (4 billion addresses) that it's so easy to brute-force the entire database that I don't see it offering any protection. If the data is stolen it will be cracked in no time, and if the data is subpoenaed that cost will likely be ruled as insufficiently "onerous". Even IPv6 doesn't save you, since the space is sparsely populated.

No, with IP logging it's all-or-nothing. You might as well store them as uint32/uint128.

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asdfaoeu13y ago

It seems most of the backlash around that was due to you suggesting you publish IP addresses. Since you are already taking credit card details I don't think people would object to recording IP addresses to prevent credit card fraud (maybe only record IP addresses for credit card transactions not general usage of the site). If someone wants to anonymously contribute they already have to get an anonymous credit card, getting around an IP address block would seem trivial.

I would also, advise against your plan to just white list givers. There are already too many barriers to contributing. I would suggest just charging and holding onto money when the transactions seem dubious. Do you also get charged the cost of fraud? because if you don't I would just charge the credit cards and forget about it and let your provider do their job.

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