Abstract:TCM provides key migration interfaces to enhance interoperability between different TCM chips, allowing users to share keys between TCMs by key migration protocols. This study finds that the conventional TCM key migration protocol, which uses the new parent key of the migrated key on the destination TCM as the migration protection key, has two weaknesses. First, keys cannot be migrated to symmetric keys, which violates the design principles of TCM. Second, the absence of authentication between the originating TCM and destination TCM allows attacker to recover the migrated key of the originating TCM and to import his key into the destination TCM. To solve these issues, the paper proposes two new TCM key migration protocols. The first protocol, compliant with the TCM specification, allows keys to be migrated to symmetric keys and provides authentication of the destination TCM. The second protocol, which requires a slight modification to TCM key migration interfaces, not only solves all the two weaknesses, but also provides prefect forward security. Finally, the study formally analyzes the two protocols and demonstrates that the proposed protocols satisfy the correctness and desired security properties.