We formally define the fungible token coloring problem of attributing (coloring) fungible tokens to originating entities (minters), and present, to our knowledge, the first practical onchain algorithm to solve it. Tracking attribution of colored tokens losslessly using existing approaches such as the Colored Coins protocol is computationally intractable due to the per-wallet storage requirements growing in proportion to the number of minters. Our first contribution is an elegant solution to the single-chain token coloring problem, where colored tokens are atomically burned and minted to ensure each wallet only contains tokens of a single color. Our second contribution is an extension to this single-chain token coloring algorithm to allow safe and efficient crosschain token transfers. We present ColorTrace, an onchain algorithm to achieve globally consistent, economically feasible, fungible token coloring.

翻译：我们正式定义了可替代代币着色问题，即如何将可替代代币归属（着色）至其原始实体（铸造者），并据我们所知，首次提出了解决该问题的实用链上算法。使用现有方法（如彩色币协议）无损追踪着色代币的归属在计算上不可行，因为每个钱包的存储需求随铸造者数量线性增长。我们的第一项贡献是针对单链代币着色问题的优雅解决方案：通过原子级销毁与铸造着色代币，确保每个钱包仅包含单一颜色的代币。第二项贡献是对该单链代币着色算法的扩展，实现了安全高效的跨链代币转移。我们提出了ColorTrace——一种实现全局一致性且经济可行的可替代代币着色的链上算法。