TLSSSH

TLSSSH is a loosely defined term that describes methods and configurations that combine TLS (Transport Layer Security) and SSH (Secure Shell) to secure communications. There is no widely adopted standard named TLSSSH. In practice, the label covers several patterns, such as tunneling TLS traffic through an SSH session, carrying SSH connections within a TLS-protected channel, or using TLS to secure an SSH proxy. The common goal is to achieve layered encryption, enhanced privacy, or traversal of restrictive networks while leveraging the authentication properties of TLS and the access controls of SSH.

Architecture and patterns include: TLS over SSH, where a client opens an SSH connection to a server and uses the SSH channel to carry a TLS session, with TLS endpoints at the far end; SSH over TLS, where the TLS session terminates on a gateway and the SSH connection traverses the TLS tunnel, potentially protecting the SSH handshake from observers; and SSH tunnel or port-forwarded TLS, where TLS traffic is forwarded through an SSH tunnel using port forwarding or a dynamic SOCKS proxy, effectively wrapping TLS in SSH. Another pattern is a TLS-protected SSH proxy to reach SSH servers behind restrictive networks. Each pattern trades off complexity, latency, and transparency.

Use cases and considerations include secure remote administration, secure tunneling, or research into hybrid security models, as well as potential benefits in privacy and access control. However TLSSSH implementations are uncommon in production, and interoperability is limited. Potential drawbacks include increased latency, configuration complexity, and the risk of misconfiguring layered encryption, which can undermine security goals.

See also: TLS, SSL, SSH, SSH tunneling, TLS over SSH, SSH over TLS, VPN.