Tmds.Ssh

Tmds.Ssh is a modern, managed .NET SSH client library for .NET 6+.

Documentation: https://tmds.github.io/Tmds.Ssh

Releases: https://github.com/tmds/Tmds.Ssh/releases

Reporting Bugs and Contributing

Found a bug or want to request a feature? Please open an issue on GitHub.

For security vulnerabilities, use GitHub's private security reporting instead.

Interested in contributing? We welcome pull requests on GitHub! Unless you're making a trivial change, open an issue to discuss the change before making a pull request.

Design

• Since SSH is a network protocol, the APIs are asynchronous and implemented using C# async and .NET's Task/ValueTask.

• For cryptographic algorithms, we use the BCL (.NET base classes) when available and otherwise we use a 3rd party library (Bouncy Castle.NET). For security reasons, we avoid implementing cryptographic algorithms ourselves*.

• The library aims to solve common SSH client use-cases similar to functionality offered by CLI tools like ssh and sftp. We do not provide an API at the SSH protocol level that enables sending custom messages or provide APIs to enable custom encryption algorithms. Such APIs are required only for a small set of use-cases but require a much larger API surface to be maintained. By keep this API internal, we are free to change it.

• SSH cryptographic algorithms continue to evolve. We aim to enable connectivity with SSH servers that (by current standards) support a secure set of algorithms. We do not add support for older (less secure/insecure) algorithms that should no longer be used.

• Performance is a goal. We aim to minimize allocations by using modern .NET primitives like Span. For SSH operations, we try to minimize latency and maximize throughput.

• Besides the SSH connection, SSH applications must deal with private keys, known hosts, connection configuration, ... The library supports using OpenSSH file formats to deal with these concerns. This provides a familiar mechanism to developers and end-users that is compatible with the OpenSSH software stack. Using the OpenSSH formats is optional, developers can choose implement their own configuration.

*: (For historic reasons) some cryptographic algorithms are included for decoding private key files. We don't consider these to impact security in any way.

CI Feed

You can obtain packages from the CI NuGet feed: https://www.myget.org/F/tmds/api/v3/index.json.