TinySSH is a minimal SSH server designed to provide secure remote shell access through a deliberately limited implementation of the SSH protocol. Rather than attempting to support every available SSH feature, the project concentrates on a small set of functionality and carefully selected cryptographic algorithms.
This approach reduces the amount of code that needs to be maintained and audited. TinySSH is particularly suited to administrators who require straightforward public-key authenticated access without the additional complexity of a general-purpose SSH server.
The software relies on external network service managers to accept incoming connections, keeping its responsibilities focused on SSH authentication and session handling.
This is free and open source software.
Key Features
- Implements a restricted subset of SSHv2, omitting password authentication, host-based authentication, SSH1 compatibility and other unnecessary functionality.
- Supports Ed25519 host keys and ChaCha20-Poly1305 authenticated encryption, avoiding legacy algorithms such as DSA, 3DES and RC4.
- Provides Curve25519 key exchange and hybrid post-quantum key exchange using sntrup761 combined with X25519.
- Supports the OpenSSH strict key-exchange extension for additional protection during SSH key negotiation.
- Does not implement TCP port forwarding, agent forwarding, X11 forwarding or compression, deliberately limiting the server’s attack surface.
- Uses fixed-size buffers for SSH packet processing, with controlled dynamic allocation for resolving authorisation paths.
- Can be started through systemd socket activation, inetd, tcpserver or compatible TCP service managers.
- Rejects client-supplied environment variable requests, requiring necessary environment settings to be configured on the server.
Website: github.com/janmojzis/tinyssh
Support:
Developer: Jan Mojžíš
License: Public Domain
TinySSH is written in C and C++. Learn C with our recommended free books and free tutorials. Learn C++ with our recommended free books and free tutorials.
Related Software
| SSH Servers | |
|---|---|
| OpenSSH | Comprehensive SSH server for secure remote access and file transfers |
| Teleport | Infrastructure access platform with SSH authentication and auditing |
| ssh3 | Faster and rich secure shell using HTTP/3 |
| TinySSH | Minimalistic SSH server |
| Dropbear | Lightweight SSH server for embedded and resource-limited systems |
| quicssh-rs | Simple ssh server |
| ssh2incus | SSH access to Incus instances without running SSH servers inside them |
| Russh | Low-level Tokio SSH2 client and server implementation |
| wolfSSH | Embeddable SSH server implementation with SCP and SFTP support |
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