US-based developers Light Protocol and Helius Labs have launched a technology called "ZK Compression" to scale applications on Solana. ZK Compression works through a process called state compression, allowing developers to use Solana's cheaper ledger space instead of its more expensive account space to store certain types of data. According to ZK Compression's documentation, a "hash" or fingerprint of off-chain data is stored on-chain for verification using a "sparse state tree". Light Protocol claims that ZK Compression will allow developers to store 100 compressed token accounts for about 400,000 of a sol, instead of the usual cost of about 0.2 sol, a price reduction of 5,000 times. According to the documentation, compressed PDA accounts can be up to 160 times cheaper. The protocol employs a small zero-knowledge proof (proof of validity) to ensure the integrity of the compressed state. According to Mert Mumtaz, founder of HeliusLabs, airdrops to 1,000,000 users/today would cost more than $260,000 for state alone/now, at just $50, it's 5,200 times cheaper.