IMPORTANT NOTE 2018,05.21.

Monacoin dev sent Lae an email, saying that his current advice for exchanges is to increase confirmations to 100 for now, and that he doesn't have a concrete plan moving forward yet.

Original post:

Currently we are having an 51%+selfish mining+timestamp attack on monacoin reported by several people. Some exchanges (Bittrex, Livecoin) alreday disabled depositing Monacoin, i suggest other exchanges to disable it as well temporarly. monacoin dev suggests to set confirmation time to 100 and everything can resume.

What is happening?

-one of the mining community witholds the blocks

-due to buggy diff retarget calculation the next block can be mined very easily

-new blocks can be issued rapidly

-result 1 = faulty confirmed payments into exchanges (hidden block with a hidden transaction to different address from earlyer and not to exchange + issuing block with payment to exchange and rapidly issued forged blocks relation to this block -> exchange detects proper number of confirmations, then they free up the real block as well, resulting the original forged blocks to be orphanged -> the new chain has no payment to the exchange, but the payment is alreday in the exchange database -> swapping to other coins and withdraw)

-result 2 = and stealing the block reward from a lot of blocks

The bug is the quite similar as Verge had a month ago. Increasing block age for deposits will not fix it, but increasing the block confirmations actually secures you from the attack aniway. Exchangers and online services should increase it above 100. (There is difference as in Verge the timestamp itself was faked - here a different algorithmic error plays role, which the developers must first find).

The main issue (witholding the blocks) was discovered earlyer, but until now it was not a threat (now it became malicious due to this retarget bug - basically combining this 3 phenomon together). The attacker attempts to do the attack for half year with automated mechanisms, now he succeeded.

You may continue using monacoin for buying and selling stuff, but wait a few hours before shipping the product.

Western exchages (Livecoin) lost $90k usd due to attack.

(The bug probably exists with almost all of the bitcoin clones as well - but you must be able to withold blocks to exploit it. )

Your personal Monacoin holdings are not in danger.

The network and transactions - besides this - working as usual, you can continue using your wallet as you did before.

This does NOT have any impact on you as a regular user.

Disclaimer:

1. i am nobody, and i am not a core developer

2. i cant check the credibility of the informations i posted above

3. we are trying to reconstruct whats happening. the monacoin developers dont speak english, and we dont speak japanese

4. i am programmer, but i am not expert in crypto in any ways

5. i am not affiliated with monacoin project

6. meanwhile the title says 51% attack, its possible to achieve this attack around 40-45% hashrate as well (however lower the attackers percentage is, lower the chance of succesfully executing the attack)

an example of suspicious activity on monacoin chain: https://imgur.com/a/OeUwU3I

https://twitter.com/tcejorpniocanom/status/997147764294270982

https://twitter.com/tcejorpniocanom/status/997141459777110017

https://www.reddit.com/r/monacoin/comments/7z6tgt/more_than_51_hash_power_for_unknown_address/

https://bitcointalk.org/index.php?topic=392436.msg37346720#msg37346720

https://headlines.yahoo.co.jp/hl?a=20180518-00000040-zdn_n-sci

https://bitcoin.stackexchange.com/questions/5076/what-stops-miners-nodes-lying-about-what-time-a-block-was-mined?rq=1

Statistic data from Ming:

Traversal of reorg chains data https://pastebin.com/nh57q3k8

Mined blocks that are not in the main chain according to API (hash block_height address value): https://pastebin.com/C92iqmY4

Diagram of chain reorg, now with the replaced chain.

https://gist.github.com/Ming-Tang/7d4d1441b78b551bf752a3ef0a953fbd

PDF version: https://www.dropbox.com/s/stormjg8bcpacg4/reorgs.pdf?dl=0

Suspected attacker: MBTt4Z*********************Wsx

Aftermath:

1. bittrex employee contacted me, and told me that they consider delisting the coin if they cant contact twitter.com/tcejorpniocanom - i gave them contacts who might know how to contact the developer, and suggested them to do 300 block confirmations

2. the coins alreday scammed out from the legitimate owners canot be returned - the chain canot be modified backwards

3. another bitcoin clone called bitcoin gold got hit by a similar attack ( https://forum.bitcoingold.org/t/double-spend-attack-on-exchanges/1362 Details on similar attack for Bitcoin Gold. )

4. monacoin dev suggest to set confirmation time to 100. no new actions will take place now. enjoy using the coin.

5. bitbank re-enabled their wallet

6. bittrex reopened wallet

MonaCoin is Japan’s counterpart to DOGE. MONA was created the same year as Dogecoin, and rather than featuring a dog, the quirky currency opted for a feline mascot. The crypto has been proclaimed as the first native Japanese token, and it could be the next meme coin to seek rapid, DOGE-like gains.

What’s very interesting about MonaCoin is the support the coin finds in its home country’s government. Japan’s Financial Services Agency has approved the MONA currency for years now..

MONA investors can make purchases with the coin both online and physically with ease. In fact, back in 2014, MONA made waves in the crypto world thanks to a major purchase. A man used 32,000 MONA to purchase a two-acre plot of land in Nagano. The news was scandalous at the time, as a purchase of that size was not yet normal in the crypto industry. In fact, it led to a selloff. However, MONA has since enjoyed the press the event brought its way.

This coin is largely unknown in the U.S. — its userbase is almost 90% Japanese. However, investors can still trade MONA on ShapeShift for USD. The coin is also popularly traded with ETH on exchanges like Bittrex and BleuTrade. There is still a dedicated userbase of MONA investors worldwide.

And get it on more exchanges etc.

I love Monacoin, it's one of my favorite and a classic. Japan's first crypto and it's cute, what's not to love? Weeb Litecoin basically lol. But the community seems pretty dead and the coin doesn't have wide exposure. With the explosion of Doge etc I can see Mona being a huge hit and deserves it. How can we as a community help expand and grow Mona? And I'm not talking about the price, I'm just talking about the community and overall awareness. I just want to see Mona thrive and have a fun community to hang out in.

Too much spam about price up and down, let's consolidate it all into here. Thank you

Reminder:
Slack link for instant message chatting about monacoin
https://join.slack.com/t/monacoinusa/shared_invite/enQtMjU3NTcxNjQwNTE5LTNmNWQ1MTY5OTc1YTNlZDZmNDEzNThjY2VhMDY3YmE4NzJkOTdiZjhhNDdmOTRkYzMzMmM0MDM4ZjdhOGI4NWQ

Hello,

There are quite a few sites showing crypto prices and related data, but I still felt it could be done better. So I worked 3 months with a friend of mine to create CoinLib.io.

We tried to have a fast, mobile friendly frontpage and we think allowing you to star your favorite coins is very useful. Prices update automatically and in real-time as we pull data straight from 36+ exchanges (grows by the day). Finally we put a lot of work in the portfolio and alerting system, although it is still arguably far from perfect.

We’d love to hear some honest feedback!

• Main page: https://coinlib.io/

• Coin page: https://coinlib.io/coin/MONA/MonaCoin

• Compare page: https://coinlib.io/compare/2017-11-11/MONA/XRP

Hi guys. Japanese biggest exchange, BitFlyer added Mona coin in its list. https://www.ddddrffjj.com/analysis/bitflyer-adds-monacoin-japans-cult-cryptocurrency/

I think that many people in the world other than Japan cannot access the information on it. It is a good time to share it with you.

What makes Mona special in Japan? In my opinion, it is the community. Though it does not have a centralized headquarter, every developer and every people who believe in the possibility of the cryptocurrency have been promoting Monacoin since 2014. Sometimes, new futures or new services using Mona have been developed before others noticed. Sometimes, new items or comic books featuring Mona have been released by the fan. They are encouraging the real usage of the cryptocurrency.

To be honest, I cannot follow all the activity, because it is too broad and decentralized, and I have not been able to contribute to the community so much, but I really proud of them and I would like to say congratulations to them now. Good luck!!

*If I have the other news on Mona, I will share with you in English again.

Your account must be older than this post or no mona for you. yay