A lot of cryptocurrency projects are using Kademlia but it's prone to vulnerabilities such as eclipse attacks.
Because peer connections are made according to deterministic rules (e.g. often based on unique Node IDs), the topology of the network can be analyzed and then the information can be exploited to disrupt the network.
There are solutions which involve making it hard to generate IDs (I've seen it done with node IDs generated using hash-based proof of work) but nowadays with all the cheap ASIC miners, you could compute these hashes much faster than any regular computer could; this means that node IDs need to be generated using top-of-the-range ASICs in order to make the network truly secure; this adds a lot of complexity when it comes to deploying a node. I don't believe that any of the existing Kademlia-based cryptocurrencies currently require sufficiently complex node IDs.
There are solutions which involve making it hard to generate IDs (I've seen it done with node IDs generated using hash-based proof of work) but nowadays with all the cheap ASIC miners, you could compute these hashes much faster than any regular computer could; this means that node IDs need to be generated using top-of-the-range ASICs in order to make the network truly secure; this adds a lot of complexity when it comes to deploying a node. I don't believe that any of the existing Kademlia-based cryptocurrencies currently require sufficiently complex node IDs.