What approach should an integration Architect recommend when an external system does not support HTTP-basic authentication for secure integration?

The most suitable approach when an external system does not support HTTP-basic authentication for secure integration is to utilize Base64 encoding for the data. Base64 encoding is a method for representing binary data in an ASCII string format. It is typically used to ensure that data remains intact without modification during transport.

While Base64 does not provide encryption or security measures on its own, it can be beneficial for encoding sensitive information in a way that prevents certain types of data corruption or misinterpretation during transit. However, it is essential to understand that Base64 should not be viewed as a security mechanism by itself; rather, it is a way to safely encode data that can then be transmitted securely through other mechanisms.

In the context provided, while the other options involve various forms of handling information and authentication, they may not appropriately address the lack of support for HTTP-basic authentication or might require additional context or methods to ensure proper security principles are adhered to. For example, digitally signing payloads adds a layer of integrity, including secret passphrases in payloads introduces potential exposure of sensitive data, and third-party SSO solutions may not be applicable or feasible based on existing system constraints. Therefore, Base64 encoding stands out as a straightforward method for data encoding when direct authentication methods