The security analyst should set up a PKI (Public Key Infrastructure) between Company A and Company B and exchange shared certificates between the two entities. This will allow them to establish a more automated approach to secure data transfers between their ERP systems. A PKI is a system that provides encryption and authentication services using public key cryptography. A PKI consists of certificates, certificate authorities (CAs), and other components that enable users to securely exchange data over untrusted networks. By exchanging shared certificates between Company A and Company B, they can verify each other's identity and encrypt their data using public and private keys.