Non-Fungible Tokens (NFTs) leverage blockchain technology to certify and transfer ownership of digital assets to individuals. NFTs on the Ethereum blockchain have garnered significant attention recently, with a trading volume of over $2 billion in Q1 2021 only. At the same time, established NFT solutions have low flexibility, limited scalability, and high transaction fees. These deficiencies make them impractical to use at a larger scale to manage digital assets. We present UniCon, a universal and scalable infrastructure for digital asset management. The key idea of UniCon is to track asset ownership in a tracking blockchain while making minimal assumptions on the capabilities of this blockchain. UniCon enables the exchange of asset ownership in any digital currency, unlike current NFT platforms. We devise a system architecture and build a prototype of UniCon. We use a scalable distributed ledger that is highly suitable for the tracking of asset ownership. Our prototype enables a decentralized ecosystem to manage and trade assets.