Tell me, WHY on earth would i care about anonymous transactions if i wanted to buy Amazon Gift Cards?
Would you want the seller to know how much money you hard? Would you want the seller to know what other vendors you buy from? Would you want the seller to know when you make all your purchases? Would you want the seller to know where your coins are coming from, and how many of them you are receiving? Most people are at least somewhat secretive of their financial information, but utilization of this information could also range from anything between advertising directed at your income level and how much they think you are willing to spend, to someone planning the best time to break into your home if they can tell you are not there since you are spending money at a particular location.
Couldn't this result in darksend transactions being exposed? If someone denominates, darksends, and then denominates again at a later time, the transaction for the second denominate will likely include both the change address for the darksend, and addresses used in the first denominate. This would link the change address to the rest of the wallet, and since there is likely to be only one corresponding output in the darksend, the darksent portion could be identified.
Even if that couldn't be done, denominating the whole wallet together allows anyone who knows one receiving address to identify most if not all of the other receiving addresses. It seems to me treating each receiving address as separate instead of operating on the whole wallet would be a safer, although more annoying, choice.
But I don't see any of that information on the blockchain. Is there more information on the blockchain that isn't covered in the explorer?
Denominates are very easy transactions to identify, as the goal is to group coins into known pooled amounts, however this seems dangerous to me, as does so creates a transaction utilizing multiple of your addresses, allowing someone to see that the same person owns them. This is purely theoretical, as I haven't tried to identify transactions with this, but here's an example of how I could see things going down.
person gets deposit from pool 2 times, of 8 drk each, into address a
person denominates, having transaction:
input: 8 from a, 8 from a
output: 10 into b, 6 into b
person darksends 6 coins to address d, and receives change into address e(addresses f,g are other peoples' inputs, h,i,j,k are other peoples' outputs and change addresses)
input: 10 from b, 10 from f, 10 from g
output: 6 into d, 4 into e, 7 into h, 3 into i, 9 into j, 1 into k
person receives another deposit from pool of 8 dark into address a
person denominates, transaction looks like:
input: 8 from a, 6 from b, 4 from e
output: 10 into m, 8 into m
The two denominates each show that all addresses involved are owned by the same person. The first denominate shows addresses a and b are the same person, and as the second denominate has a and b also, it shows e and m are also the same person's addresses. As b is used as a darksend input, and e(now known to be the same person's address) is used as an output in the same transaction, unless the person is darksending to themselves, e is known to be that person's change for that transaction. As there is only one other output where 0drk <= 10 - e - output_amount < 1drk, the matching output, 6 to d, can be identified as this person's darksend amount and target.
I hope I'm wrong, but that's what it looks like to me anyway. Maybe denominate can be pooled also, and use a different address for each output?