An Application-Specific Integrated Circuit (ASIC) is a computer chip that is built specifically for a single function. For mining, ASICs are used to compute for specific hashing algorithms. They pose a risk to decentralisation because they are manufactured by specific companies and have very limited distribution channels due to the specialised nature of the hardware. To prevent ASIC miners from monopolising the network hashrate, many cryptocurrencies developed ASIC resistant hashing algorithms, like Scrypt and Ethash.