What encryption algorithms does Secure Shell use?
SSH architecture The SSH-2 protocol has a clean internal architecture (defined in RFC 4251) with well-separated layers. These are: The transport layer (RFC 4253). This layer handles initial key exchange and server authentication and sets up encryption, compression and integrity verification. It exposes to the upper layer an interface for sending and receiving plaintext packets of up to 32,768 bytes each (more can be allowed by the implementation). The transport layer also arranges for key re-exchange, usually after 1 GB of data has been transferred or after 1 hour has passed, whichever is sooner. The user authentication layer (RFC 4252). This layer handles client authentication and provides a number of authentication methods. Authentication is client-driven, a fact commonly misunderstood by users; when one is prompted for a password, it may be the SSH client prompting, not the server. The server merely responds to client’s authentication requests. Widely used user authentication method
