i am a bitcoin researcher and i want to know what are some security protocols/software which can be used to secure the bitcoin network from selfish mining attack..
You mean a 51% attack?There's no protection against it ( atleast in the bitcoin protocol), other then that it is a pretty unprofitable thing to do in the long run, as it would probably create alot of panic, causing not only the bitcoin price to go down, but also the value that your mining equipment has, etcetera.
OR, did you actually mean the >25% attack?
There's some good resources here, (
https://arxiv.org/pdf/1311.0243v2.pdf) in which various solutions are described, some have been implemented i believe, but most haven't.
There have been BIPS, Bitcoin Improvement Proposals, to lower the probability of a selfish mining attack such as randomly assigning miners to various branches when a fork occurs – or alternatively providing a threshold limit to which a mining pool can reach. This is the same as Governments trying to halt natural monopolies to allow competition.
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Ethereum/ other upcoming PoS coins do however have some sort of protection against them, I had some good sources but i lost them.
Ability to use economic penalties to make various forms of 51% attacks vastly more expensive to carry out than proof of work - to paraphrase Vlad Zamfir, "it's as though your ASIC farm burned down if you participated in a 51% attack".
https://github.com/ethereum/wiki/wiki/Proof-of-Stake-FAQ
