Kaspa is a proof-of-work cryptocurrency which implements the PHANTOM GHOSTDAG protocol. Unlike traditional blockchains, GHOSTDAG does not orphan blocks created in parallel, rather allows them to coexist and orders them in consensus. Whereby our blockchain is actually a blockDAG; you can see GHOSTDAG in action in a real time blockDAG visualizer. This generalization of Nakamoto consensus allows for secure operation while maintaining very high block rates (currently one block per second, aiming for 10/sec, dreaming of 100/sec) and minuscule confirmation times dominated by internet latency (cf. chapter 6 of the the paper for some initial benchmarks). The Kaspa implementation includes a lot of cool features and subprotocols including Reachability to query the DAG's topology, Block data pruning (with near-future plans for block header pruning), SPV proofs, and later subnetwork support which will make future implementation of layer 2 solutions much easier.
Kaspa is a community project, completely open source, no central governance, no biz model. Think Bitcoin, Litecoin, Monero, Grin, Kaspa. The mainnet was openly launched without premining or any other preallocation of coins. Kaspa was created by DAGlabs.
So far Kaspa is the only coin which achieves scalable throughput and immediate confirmations based on simple POW principles alone. The simplicity of Kaspa protocol makes it provably secure, which could not be said for any POS coin (since that is an outstanding open problem). Kaspa manages to achieve high performance using only rudimentary and well understood tools. At the core, it is a very gentle and "not fancy" generalization of the Nakamoto consensus. At the same time, Kaspa is a classic decentralized solution, unlike fast but by definition centralized coins such as Solana, Ripple and others alike.
Please find some useful links to better understand what Kaspa is and what is its background
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