<p>With the diversification of IoT application scenarios, various sensors with different functions are now integrated into IoT devices. As the premise of mutual trust between devices, cross-domain identity authentication has become the key to sharing sensor data and promoting cooperation and interoperability in multiple fields. Currently, most of the existing cross-domain authentication methods are based on the premise that two management domains use the same authentication scheme, and require additional deployment costs, making it difficult to use and promote the scheme. To solve the above problems, this paper proposes a heterogeneous cross-domain authentication method CABR based on ring signature and blockchain. CABR can achieve secure and efficient cross-domain authentication of PKI and IBC heterogeneous domains based on the original identity authentication methods, and has certain conditional privacy. Finally, we evaluate the performance of CABR through simulation experiments and compare it with other cross-domain authentication schemes to prove its security and effectiveness.</p>