Due to the differences in the underlying protocols and technical architectures of different blockchains, it is difficult to effectively exchange digital assets between chains. Currently, digital currency exchanges are the main platforms for digital asset exchanges. However, the existing centralized exchanges store users’ funds, which are vulnerable to hacker attacks, internal theft, or exchange escapes and other security issues. Existing decentralized exchanges are limited by the block generation time and confirmation speed of the blockchains participating in the cross-chain, which affects transaction efficiency. And there are fewer order types and functions in decentralized exchanges. In order to solve the above problems, we implement a decentralized multi-party transaction scheme through distributed key generation and attribute-based encryption. The user’s assets are pledged to the distributed network through distributed key generation to realize a decentralized asset management model. The distributed network generates an equivalent amount of digital asset tokens for users on the transaction blockchain, enabling users to use tokens for transactions on the transaction blockchain, and then to go to the distributed network to extract the corresponding digital assets according to the token ownership certificate. Users realize transaction control through attribute-based encryption, and use asset type, amount, exchange rate and time as attributes to set up diversified access control strategies. Transaction objects that meet the user’s policy can be traded with the users. The smart contract service provided by the transaction blockchain can realize diversified transaction options for users and provide users with fair exchange services. We verify the feasibility of the scheme through experiments. The efficiency of cross-chain is limited by the distributed key generation algorithm and the blockchain itself participating in the cross-chain when locking and extracting assets. In the multi-party transaction system, the transaction efficiency is only related to the transaction blockchain.