So I got this question today, and thought it would be a great subject to take up on steemit.

"With coins like NEO going up with a rapid rate, I'm curious to what could possibly make such a coin die for good"

This is a super great question that's being overlooked a lot since everyone, wants to promote coins for their personal gains and never talk about the downside. I will go over some scenarios that could potiential end Bitcoin and other cryptocurrencies.

Keep in mind, that most of the problems can be fixed and the network is grown so big that there is s a very small chance of this occurring and I'm a big supporter of bitcoin and other currencies.

Before I begin, it's important to understand some of the encryption method bitcoin use and how a public encryption works. Here is a great post about it .https://www.reddit.com/r/explainlikeimfive/comments/1jvduu/eli5_how_does_publicprivate_key_encryption_work/cbiv6mv/

Might be a problem 3 things below.

1 - 🔴

http://www.irnclinks.net/wp-content/uploads/2015/08/Data_Security_.png

Cryptographic failure is probably the biggest one. secp256k1 failing would kill Bitcoin and other coins like Ethereum, QC would kill elliptic curve cryptography and most coins.

Now you thinking what the hell is secp256k1, Super complicated language. I will try explain.

All of Bitcoin's public-key cryptography is done with secp256k1. Every sane transaction has at least one secp256k1 signature and at least one secp256k1 public key or public key hash (address). A complete overnight failure of ECDSA/secp256k1 is the only technical failure which could destroy Bitcoin.

If you wondering how an transaction works on the bitcoin network please visit this link : https://www.coindesk.com/information/how-do-bitcoin-transactions-work/

2 - 🔴

https://bitcoin.org/img/video/video_wuc.jpg

Bitcoin are an apathetic community of miners and quantum computing. Without a responsive mining community able to defensively fork against real threats in the coming decade bitcoin will be paralyzed and unable to respond to changing conditions.

3 - 🔴

Timejacking

An attacker could potentially slow down or speed up a node's network time counter by connecting as multiple peers and reporting inaccurate timestamps. (A relatively small number of Tor clients could send enough messages to take over the node's median time.)

https://vivmayuk.files.wordpress.com/2012/12/time-stealer.jpg?w=584
An advanced attack would involve speeding up the clocks of a majority of the network's mining resources while slowing down the target's clock. Since the time value can be skewed by at most 70 minutes, the difference between the nodes would be 140 minutes.

More information about this here :

http://culubas.blogspot.dk/2011/05/timejacking-bitcoin_802.html

If you would like me to do more posting about cryptocurrencies, you can follow me and maybe comment with your biggest fear of the future with cryptocurrencies.

Thank you for reading!