A cryptocurrency exchange portal has a key management service hosted in their on-premises data center, which stores encryption keys and uses an RSA asymmetric encryption algorithm. The company has recently implemented a hybrid cloud architecture in AWS and you were assigned to migrate the exchange portal to their cloud infrastructure. For security compliance, the keys should be stored in dedicated, third-party validated hardware security modules under your exclusive control. Which of the following is the BEST solution that you should implement to meet the above requirement?