Intersango exchange (formerly Britcoin)

[phantomcircuit]

Is it 0% commission?  If so, that may be worth mentioning, since the competition isn't.

It is.

[dazedtrader]

Just a heads up - the ticker API seems to be broken as it is returning:

Code:

{"ticker": {"vol": 561.62370667, "buy": 8.4035, "sell": 8.65,
Warning: Division by zero in /var/www/britcoin.co.uk/htdocs/api/ticker.php on line 72
"last": }} 

[dazedtrader]

It looks like a trade of amount 0 has gone through and has caused the problem. This is the culprit:

Code:

{"date": 1311104701, "price": , "amount": 0}

I also noticed a trade in the order book earlier today where one of the quantities was zero so looks like the validation may need tightening up somewhere. (Edit: that's a guess, I haven't read the code in any detail)

[phantomcircuit]

It looks like a trade of amount 0 has gone through and has caused the problem. This is the culprit:

Code:

{"date": 1311104701, "price": , "amount": 0}

I also noticed a trade in the order book earlier today where one of the quantities was zero so looks like the validation may need tightening up somewhere. (Edit: that's a guess, I haven't read the code in any detail)

That's a good guess.

The issue is that 2 trades went through in which one side got 0.

| 16947 |     18518 |        1 |     18539 |        0 | 2011-07-19 18:44:01 |
| 16973 |     18548 |        2 |     18562 |        0 | 2011-07-19 20:45:01 |

Those numbers are scaled 10^8, so those are trades for 0.00000001 for 0 and 0.00000002 for 0.

[dooglus]

What happened to the limits of 0.005 or so?  On britcoin there's a minimum size for both BTC and GBP, and it's something of that order.

Isn't this USD exchange using the same code?

[phantomcircuit]

What happened to the limits of 0.005 or so?  On britcoin there's a minimum size for both BTC and GBP, and it's something of that order.

Isn't this USD exchange using the same code?

The limits on britcoin are artificial.  The actual precisions is 8 places after the decimal, or 0.00000001.

[dooglus]

The limits on britcoin are artificial.  The actual precisions is 8 places after the decimal, or 0.00000001.

Of course, but since britcoin is using the intersango code I'd have thought the same artificial limits would be in place for the USD exchange too.  The artificial limits were put in place for a reason (it helps prevent these zero trades and code errors, for one thing), so it seems odd that they're not on all the intersango exchanges.

[phantomcircuit]

The limits on britcoin are artificial.  The actual precisions is 8 places after the decimal, or 0.00000001.

Of course, but since britcoin is using the intersango code I'd have thought the same artificial limits would be in place for the USD exchange too.  The artificial limits were put in place for a reason (it helps prevent these zero trades and code errors, for one thing), so it seems odd that they're not on all the intersango exchanges.

What I posted where trades, probably the tail end of orders for normal amounts.

[dazedtrader]

The zero trades I saw were on Britcoin, by the way.

[dooglus]

The zero trades I saw were on Britcoin, by the way.

Curiouser and curiouser. 

[dooglus]

If I can sell 0.00000000 BTC for 0.00000001 GBP, I could do that 100 million times and make a whole British Pound!  I wonder how you get around the limits.

The code is doing:

Code:

order_worthwhile_check($amount, $amount_disp, '0.0005');
order_worthwhile_check($want_amount, $want_amount_disp, '0.0005');

[dazedtrader]

It's just happened again: https://britcoin.co.uk/api/ticker.php

[phantomcircuit]

If I can sell 0.00000000 BTC for 0.00000001 GBP, I could do that 100 million times and make a whole British Pound!  I wonder how you get around the limits.

The code is doing:

Code:

order_worthwhile_check($amount, $amount_disp, '0.0005');
order_worthwhile_check($want_amount, $want_amount_disp, '0.0005');

That check is for the order as a whole, not for the partial orders produced when a trade occurs.

So if you place an order 1 BTC for 10 GBP and it gets filled as 0.99999999 BTC you will have a remaining partial order of 0.000000001 BTC.

So this isn't something that's exploitable, basically peoples orders are getting rounded up or down by very small amounts of 0.00000001 for the entire order.

So in the worst case someone might have 0.002% of their order rounded off.

[dooglus]

So in the worst case someone might have 0.002% of their order rounded off.

Someone recently had 0.00000002 of their order rounded off didn't they?

If their total order was 0.0005 (the minimum), that's 0.004%.

That's twice as bad as your stated worst case.

Is it possible to have 0.00000003 or more rounded off?  What's the real worst case?  And can this be fixed?

[Calibre]

Is Britcoin down? No updates on bitcoincharts since 13:42 and the site is not loading....

[spruce]

Is Britcoin down? No updates on bitcoincharts since 13:42 and the site is not loading....

http://www.downforeveryoneorjustme.com/http://britcoin.co.uk/

I check it a couple of times a day and it's usually up. I wouldn't worry about it.

[Donald_Norman]

Britcoin was down for a bit today. Excuse the interruption of service.

[alan2here]

I love Britcoin. I hope I don't sound like a fanboy elsewhere on the forums, but it just makes everything so straightforward.

[willphase]

I love Britcoin. I hope I don't sound like a fanboy elsewhere on the forums, but it just makes everything so straightforward.

yup I agree - don't know why people don't use their sister site https://intersango.us/ either - 0% commission seems like a no brainer - is it the difficulty of getting funds in/out?

Will

[alan2here]

It's easier than any other similar service to get coins in and out.