Unspent Transaction Output (UTXO) set is the foundational model used in many blockchain systems to represent assets. The benefits of UTXO representation include parallel processing, privacy, etc. However, the increasing size of UTXO set is degrading the access performance and severely brings down the validation speed of blockchain further, especially in resource-constrained scenerios, such as IoT. In this paper, we present a memory-economical storage system for UTXO-based blockchain. Based on the inherent properties of UTXO set, we propose two lossless compression techniques to reduce the memory space occupied by UTXO set. Besides, the database related operations are adapted to make the proposed mechanism easily applied in current blockchain system. Taking Bitcoin as the object of study, our mechanism can deliver 2.9-4.5x memory reduction and orders of magnitude validation speed improvement in resource-constrained situations. This compact system will improve validation performance and extend applied scope of blockchains.

未用交易输出（UTXO）集是许多区块链系统中用来表示资产的基本模型。UTXO表示的好处包括并行处理，隐私等。但是，UTXO集的增加会降低访问性能，并严重降低区块链的验证速度，尤其是在物联网等资源受限的场景中。在本文中，我们提出了一种基于UTXO的区块链的经济型存储系统。基于UTXO集的固有特性，我们提出了两种无损压缩技术来减少UTXO集所占用的存储空间。此外，数据库相关操作适用于使所提出的机制易于在当前区块链系统中应用。以比特币为研究对象，我们的机制可以实现2.9-4。在资源受限的情况下，内存减少了5倍，验证速度提高了几个数量级。这个紧凑的系统将提高验证性能并扩展区块链的应用范围。