An achievement in providing worldwide Internet security was the signing of certificates associated with which of the following protocols?

TCP/IP is the foundational networking protocol suite that handles packet routing and transmission but does not use certificates or provide application-level encryption.

SSL introduced the PKI-based model where Certificate Authorities digitally sign server certificates, allowing browsers worldwide to verify website identities and establish encrypted HTTPS sessions. This certificate-signing infrastructure became the foundation for secure e-commerce and global Internet trust, and is the direct predecessor to the modern TLS protocol.

SCP is used for encrypted file transfers over SSH and relies on SSH host keys rather than the globally distributed CA-signed certificate model associated with Internet-wide security.

SSH uses public key cryptography for authentication but its certificate and trust model is not the globally recognized PKI achievement that enabled widespread secure web browsing.