bitcoin/bitcoin — pull request #1536 by coblee (2012-06-29 19:15:38+00:00)
Title: improve dust spamming prevention algorithm

This code helps with reducing dust spam. The original code will make the transaction fee become the minimum fee if any output is less than a cent. This makes it costly to send dust spam, but there's an edge case. The attacker can send a transaction with 1000 outputs of one satoshi each. The transaction size is huge but the fee is only the base fee. This fix will increase the fee by the base fee amount for each output that's less than a cent.