Mitigating data growth in PoW blockchains: Storage reduction methods for scalability without compromising decentralization

The exponential growth of data volume in Proof-of-Work (PoW) blockchains threatens their decentralization. The article provides a systematic analysis of data growth mitigation methods (sharding, block pruning, off-chain storage etc.), identifying their key flaws: compromised auditability, increased synchronization complexity or centralization. To address the issue, a novel Periodic Aggregation with Dual Hash Anchoring (PADHA) method is proposed. Its key innovation is the synergy of data pruning and the controlled use of chameleon hash functions. The method enables linear reduction of stored history by creating final state aggregators and subsequent secure «cleansing» of blocks from past epochs. PADHA preserves cryptographic chain integrity and PoW support without trusted third parties. The method is designed for Fact-Oriented Blockchains that store final data states (facts), making it promising for registries, IoT and other applications where current information, not its change history, is critical.