Quote from: coblee on November 21, 2011, 12:18:49 PM

Quote from: coblee on November 21, 2011, 10:59:31 AM

Quote from: localhost on November 21, 2011, 10:06:37 AM

I don't really understand the inner workings of those transactions (and I'm just discovering about relay fees), but I guess if there was a way to make the transaction fee work per receiving address (like, sending 0.000001 LTC 100 times to different addresses or even from the same address to the same address = paying 100*0.1=10 LTC in transaction fees) this would impair his ability to cheaply make large transactions while not being an issue for legitimate users.

Here's my latest thought. I can force a transaction fee for each output greater than 2. Normal users will only send transactions to 1 address with a address for the change. Only advanced users will use the sendmany api to send coins to many address at once. I can force a fee to use the sendmany feature. So for every output greater than 2, you have to pay an additional 0.1 LTC fee. Without the ability to send to multiple addresses at once, I don't think the spammer can bloat the chain cheaply anymore.

This might not be the best idea. Might work in the short term, but in the long term we probably don't want to do that. The main reason to use sendmany is to limit chain growth, so seems kind of silly to punish use of it. The idea I was going with is to punish someone for sending dust spam. Here's the original code:

// To limit dust spam, require MIN_TX_FEE/MIN_RELAY_TX_FEE if any output is less than 0.01
if (nMinFee < nBaseFee)
BOOST_FOREACH(const CTxOut& txout, vout)
if (txout.nValue < CENT)
nMinFee = nBaseFee;

Basically, we were setting min fee to at least 0.1 LTC if any of your output is less than 0.01 LTC. I'd like to extend that to add 0.1 LTC for every output less than 0.01 LTC. So using sendmany to send to 1000 outputs is fine as long as you are paying the 0.1 LTC fee per 1000 bytes. But if you are sending 0.00000001 LTC to each of those 1000 outputs, then you need to pay an additional 100 LTC in fees.

// To limit dust spam, add MIN_TX_FEE/MIN_RELAY_TX_FEE for any output is less than 0.01
BOOST_FOREACH(const CTxOut& txout, vout)
if (txout.nValue < CENT)
nMinFee += nBaseFee;

The spammer can still send a ton of 0.01 outputs, but this will deal with the dust spam. It's really hard for the receiving end to collect these worthless transactions.

Here's this code in action on the testnet: http://blockexplorer.sytes.net/block/d1d987e3674b5f17a7881220376fb97aad9ec31880ac87b225c8dad5801dd215
Each output that is less than a litecent adds an additional 0.1 LTC fee.