Transport Layer Security (TLS) is the most suitable solution as it is designed to provide privacy and data integrity between two or more communicating computer applications. It encrypts the data, ensuring that it remains confidential, and authenticates the communicating parties to reduce the chance of impersonation. TLS also provides integrity checks on the data to ensure that it has not been tampered with during transit. Alternative protocols like SSH are primarily used for secure command-line access and management. While PEM files are related to certificates, they aren't a standalone solution for secure communication. IPsec may also be used, but it is typically implemented for securing VPN connections rather than securing web server communications.