Zerocoin implementation bug

[John Titor]

https://news.ycombinator.com/item?id=13673214 I came across this post on Hacker News.  ZCash Devs basically claiming that Poramin Ipsom basically just copy/pasted code from the original bitcoin code, and that lazy code work allowed for a double spend.  If true, it's kind of surprising that this kind of bug wasn't caught sooner; along with Poramin being the only dev for ZCoin, and the drama with co-founder Gary Lee, I'd say it might be time to jump ship.

I bought in around 30-70k sats range, and I am very thankful that the price hasn't tanked yet and I was able to liquidate 80% of what I purchased, and get out with a solid profit.  Provided that no new information comes in from Poramin giving a reasonable explanation/defense for this, I'd have to recommend others do the same.

[jeremy grol]

Poramin and gary: both scammers.

[simonbtc]

There's also an equality vs assignment bug which impacts how the wallet tracks (or doesn't correctly track?) serial numbers of spent private coins:

https://makebitcoingreatagain.wordpress.com/2017/02/18/is-the-zcoin-bug-in-checktransaction/#update4

[almightyruler]

There's also an equality vs assignment bug which impacts how the wallet tracks (or doesn't correctly track?) serial numbers of spent private coins:

https://makebitcoingreatagain.wordpress.com/2017/02/18/is-the-zcoin-bug-in-checktransaction/#update4

zccoinSpend.denomination == libzerocoin::ZQ_LOVELACE;

Ouch. Another bit of dead code that would have been completely ignored by the compiler. I wonder if it emits a warning that the code doesn't actually do anything?

[JosNekoKopa]

All this has been for expecting, and who know how all this is going to be ended. I don't understand only how Bittrex did not found those code mistakes, they also can be endangered this way. I thought, they checks code before adding it.

[Mallyx]

All this has been for expecting, and who know how all this is going to be ended. I don't understand only how Bittrex did not found those code mistakes, they also can be endangered this way. I thought, they checks code before adding it.

They are checking codes only to find malicious, it's not a full review.

[JosNekoKopa]

They are checking codes only to find malicious, it's not a full review.

What is worse of this, i mean someone created coins from the nothing, and dumped at Bittrex users. In case of malicious code he won't damage only users, he could still and from house, and what we got? House who doesn't care about its users.

[almightyruler]

They are checking codes only to find malicious, it's not a full review.

What is worse of this, i mean someone created coins from the nothing, and dumped at Bittrex users. In case of malicious code he won't damage only users, he could still and from house, and what we got? House who doesn't care about its users.

Manual code review is labour intensive, and prone to errors. The more the source code deviates from a known reference, the more work it is to review. A cloned shitcoin may only have a small number of changes, but it looks like zcoin has quite a bit of unique code.

There are some programs that can analyze code and help point to potential problems, like undefined behaviour, but they won't catch silly mistakes like using the wrong constant.

[JosNekoKopa]

#almightyruler
You are right this is very hard work and mistakes can happen, but for coins that actually promoting
 something abstract like zero knowledge or anonymous transactions code must be perfect.

[Hueristic]

It's an inherent bug intentionally put there then exploited to dump on those stupid enough to buy in. Just a scam like all the rest. Really no-one has seen this pattern from this dev? In that case you all deserve to lose from sheer idiocy.

[playingpoodles]

Very likely an inside job.

Which is more likely:

(a) a random outsider on the internet targets obscure cryptocurrency worth less than $10 million instead of much more valuable currencies, pores over their code, finds and exploits a bug that escaped developers, and developers do not notice the mismatch between mint and spend until over 20% of total supply has been maliciously created?

(b) developers (or some of them) of Zcoin notice a bug or deliberately create one in the first instance, when Zcoin doesn't take off quickly enough to make them millionaires off of their 20% shared founders reward, they exploit the bug. After they maliciously create over 20% of total supply they decide that is sufficient to help their present financial needs and any more will spook the market. Then they stage-manage a bug announcement stressing that as almost all the 370,000 maliciously created coins are already sold on the market and won't be dumped the market shouldn't worry?

See my Reddit post for more detail https://www.reddit.com/r/CryptoCurrency/comments/6379u9/zcoin_bug_a_deliberate_inside_job/

[CorePrime95]

Zoin also had this bug (as it is a Zerocoin fork) but is now fixed: https://bitcointalk.org/index.php?topic=1671060.0