---
title: "NanoSSH Server overview"
source_url: https://dev.digicert.com/trustcore-sdk/nanossh/nanossh-server-user-guide/nanossh-server-overview.html
---

TrustCore SDK NanoSSH Server enables a secure connection to remote clients, which may be running NanoSSH Client or any other SSH client.

<a id="features"></a>

## Features

- Small memory footprint
- Speeds integration and testing of complex cryptographic functions for your product
- SSHv2 compliant
- TCP/IP-neutral
- Certificate support, per RFC 6187
- Re-keying at will, based on a specified number of packets or a certain amount of time
- Support for TPM-generated keys
- OS- and platform-agnostic for easy portability
- Threadless architecture, synchronous and asynchronous
- Guaranteed GPL-free code that protects your intellectual property

<a id="supported-rfcs"></a>

## Supported RFCs

NanoSSH supports the following RFC standards:

- SSH File Transfer Protocol, v2, v3 and v4
- RFC 4250: The Secure Shell (SSH) Protocol Assigned Numbers
- RFC 4251: The Secure Shell (SSH) Protocol Architecture
- RFC 4252: The Secure Shell (SSH) Authentication Protocol
- RFC 4253: The Secure Shell (SSH) Transport Layer Protocol
- RFC 4254: The Secure Shell (SSH) Connection Protocol (partially supported)
- RFC 4344: The Secure Shell (SSH) Transport Layer Encryption Modes
- RFC 4335: The Secure Shell (SSH) Session Channel Break Extension
- RFC 4419: Diffie-Hellman Group Exchange for the Secure Shell (SSH) Transport Layer Protocol
- RFC 4432: RSA Key Exchange for the Secure Shell (SSH) Transport Layer Protocol. For detailed information refer to section 7 of the RFC draft-ietf-secsh-filexfer-03.txt, SSH File Transfer Protocol (http://tools.ietf.org/html/draft-ietf-secsh-filexfer-03).
- RFC 6187: X.509v3 Certificates for Secure Shell Authentication
- RFC 6239: Suite B cryptographic suites for SSH
- Draft-green-secsh-ecc-07: Elliptic-Curve Algorithm Integration in the Secure Shell Transport Layer
- Draft-igoe-secsh-aes-gcm-02: AES Galois Counter Mode for the Secure Shell Transport Layer Protocol
- Draft-josefsson-ssh-chacha20-poly1305-openssh-00 - ChaCha20 Poly1305 for the Secure Shell Transport Layer Protocol
- Draft-ietf-curdle-ssh-ed25519-02 - Ed25519 for Secure Shell Transport Layer Protocol

<a id="apis"></a>

## APIs

TrustCore SDK NanoSSH server is implemented by the following ANSI C APIs:

- **Common code base:** Functions common to all TrustCore SDK components; defined in src/common/mocana.h.
- **SSH synchronous server:** Functions to implement synchronous communication between a NanoSSH server and any peer; defined in src/ssh/ssh.h.
- **SSH asynchronous server:** Functions to implement asynchronous communication between a NanoSSH server and any peer; defined in src/ssh/ssh.h.
- **SFTP server:** Functions to implement secure file transfer; defined in src/ssh/sftp.h and src/ssh/ssh_ftp.h.