How can I prevent an instamine to occur when launching my own altcoin?

[Abiky]

I'm becoming more interested into creating my own alternative cryptocurrency for fun and learning, and to be used by anyone in the world sometime in the future.

However, I have seen that some altcoins have a mining scheme which allows them to become instamined, thus making them worthless in terms of value.

Thus, I would need to make sure that the mining design of my currency would prevent this from ocurring, and make it mineable for years to come.

Nevertheless, I would like to know what would be your thoughts or advice when designing the mining scheme for an altcoin, to help keep the process smooth over the years, preventing the coin from becoming mined instantly. 

[NeuroticFish]

A few ideas that come into my mind on this subject are:
* You can make the first x block give very small amounts of your coin. This way nobody can claim it was instamine. Just make sure the real reward starts before people lose interest
* You can later do something like XMG does: if the difficulty rises too much the reward starts to fall. This way you can keep the whales away and have a core of smaller miners; just less investment in hardware may make the price fall sooner or later, the history seems to tell.
* The emission of XMR looks better than the one for BTC.
* A brand new algo may also ensure that people will mine at start with CPU; GPU would come later and even more powerful devices even later, keeping the interest in the coin.


However, if you do this for hobby, with no utility, the coin will have no value thus the miners will have not much of a reason to mine it....

[bathrobehero]

- Have the first couple hundred blocks contain no rewards (or very slim rewards)
- Have a proper difficulty retargeting logic*
- Or mabye start the coin with higher than default difficulty from block 1 (advanced)

*But if you're going to use an ASIC friendly algo (SHA256, Scrypt, X11, etc) I recommend using more than just one PoW algo working in parallel (Joincoin, DigiByte, Aurora, etc, work like that, or you can just add PoS on top of PoW) because every difficulty retarget works based on the time between blocks but since ASICs are so fast, a single difficulty retarget will either overcompensate (difficulty gets way too high and blockchains slows down or stops for a long time) or just doesn't increase the difficulty high enough (eg. flash/instamining). Even with non-ASIC coins the result is the same if a big farm (or multipool) joins the coin then leaves when the difficulty goes up.
If you have more PoW algos, let's say Scrypt and Qubit, and let's say the Scrypt difficulty goes super high because of an ASIC farm mining for a few hours then leaving, everytime there's a Qubit block found, the now super high difficulty of the Scrypt PoW can be reduced because the difficulty retarget doesn't get stuck with the single PoW.

I'm a GPU miner but I'd advise not using an ASIC algo because way more people have GPUs than ASICs so distribution would somewhat better.

[Abiky]

A few ideas that come into my mind on this subject are:
* You can make the first x block give very small amounts of your coin. This way nobody can claim it was instamine. Just make sure the real reward starts before people lose interest
* You can later do something like XMG does: if the difficulty rises too much the reward starts to fall. This way you can keep the whales away and have a core of smaller miners; just less investment in hardware may make the price fall sooner or later, the history seems to tell.
* The emission of XMR looks better than the one for BTC.
* A brand new algo may also ensure that people will mine at start with CPU; GPU would come later and even more powerful devices even later, keeping the interest in the coin.


However, if you do this for hobby, with no utility, the coin will have no value thus the miners will have not much of a reason to mine it....

- Have the first couple hundred blocks contain no rewards (or very slim rewards)
- Have a proper difficulty retargeting logic*
- Or mabye start the coin with higher than default difficulty from block 1 (advanced)

*But if you're going to use an ASIC friendly algo (SHA256, Scrypt, X11, etc) I recommend using more than just one PoW algo working in parallel (Joincoin, DigiByte, Aurora, etc, work like that, or you can just add PoS on top of PoW) because every difficulty retarget works based on the time between blocks but since ASICs are so fast, a single difficulty retarget will either overcompensate (difficulty gets way too high and blockchains slows down or stops for a long time) or just doesn't increase the difficulty high enough (eg. flash/instamining). Even with non-ASIC coins the result is the same if a big farm (or multipool) joins the coin then leaves when the difficulty goes up.
If you have more PoW algos, let's say Scrypt and Qubit, and let's say the Scrypt difficulty goes super high because of an ASIC farm mining for a few hours then leaving, everytime there's a Qubit block found, the now super high difficulty of the Scrypt PoW can be reduced because the difficulty retarget doesn't get stuck with the single PoW.

I'm a GPU miner but I'd advise not using an ASIC algo because way more people have GPUs than ASICs so distribution would somewhat better.

Thanks guys for your helpful advice. I'll put them in mind when launching my very own alternative cryptocurrency, as I want to make it a fairly distributed coin, while at the same time being very scarce, making it a very valuable coin in the long term.

I will try to make it as closely as possible from BTC, with a few changes like hashing algorithm, and supply.

Even though I have been clarified about how to prevent an instamine to occur, I still got a lot to learn to be able to make a flawless altcoin of my own.