This drops some of the algorithms long-considered legacy/insecure. The idea is both to improve the theoretical security of the library by not offering these algorithms, and to improve the practical security of the library by not having hand-written, barely tested crypto code. The overarching goal is for the library to have minimal exposure to crypto implementation, relying firstly on the .NET base libraries, and secondly on third-party providers, such as BouncyCastle. This change covers deleting the cipher algorithms arcfour, blowfish, twofish, cast. It covers deleting the MD5-based and truncated HMAC algorithms. These were all disabled in OpenSSH server (sshd) in 2014[^1]: > sshd(8): The default set of ciphers and MACs has been altered to > remove unsafe algorithms. In particular, CBC ciphers and arcfour* > are disabled by default. > > The full set of algorithms remains available if configured > explicitly via the Ciphers and MACs sshd_config options. and in the client in 2016[^2]: > This release disables a number of legacy cryptographic algorithms > by default in ssh: > > * Several ciphers blowfish-cbc, cast128-cbc, all arcfour variants > and the rijndael-cbc aliases for AES. > > * MD5-based and truncated HMAC algorithms. > > These algorithms are already disabled by default in sshd. This change also drops PKCS5Padding, which is a line-for-line copy of PKCS7Padding, and StreamCipher, which is now unused (and useless anyway). [^1]: https://www.openssh.com/txt/release-6.7 [^2]: https://www.openssh.com/txt/release-7.2 Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
SSH.NET
SSH.NET is a Secure Shell (SSH-2) library for .NET, optimized for parallelism.
Key Features
- Execution of SSH command using both synchronous and asynchronous methods
- SFTP functionality for both synchronous and asynchronous operations
- SCP functionality
- Remote, dynamic and local port forwarding
- Interactive shell/terminal implementation
- Authentication via publickey, password and keyboard-interactive methods, including multi-factor
- Connection via SOCKS4, SOCKS5 or HTTP proxy
How to Use
Run a command
using (var client = new SshClient("sftp.foo.com", "guest", new PrivateKeyFile("path/to/my/key")))
{
client.Connect();
using SshCommand cmd = client.RunCommand("echo 'Hello World!'");
Console.WriteLine(cmd.Result); // "Hello World!\n"
}
Upload and list files using SFTP
using (var client = new SftpClient("sftp.foo.com", "guest", "pwd"))
{
client.Connect();
using (FileStream fs = File.OpenRead(@"C:\tmp\test-file.txt"))
{
client.UploadFile(fs, "/home/guest/test-file.txt");
}
foreach (ISftpFile file in client.ListDirectory("/home/guest/"))
{
Console.WriteLine($"{file.FullName} {file.LastWriteTime}");
}
}
Main Types
The main types provided by this library are:
- Renci.SshNet.SshClient
- Renci.SshNet.SftpClient
- Renci.SshNet.ScpClient
- Renci.SshNet.PrivateKeyFile
- Renci.SshNet.SshCommand
- Renci.SshNet.ShellStream
Additional Documentation
Encryption Methods
SSH.NET supports the following encryption methods:
- aes128-ctr
- aes192-ctr
- aes256-ctr
- aes128-gcm@openssh.com (.NET 6 and higher)
- aes256-gcm@openssh.com (.NET 6 and higher)
- aes128-cbc
- aes192-cbc
- aes256-cbc
- 3des-cbc
Key Exchange Methods
SSH.NET supports the following key exchange methods:
- curve25519-sha256
- curve25519-sha256@libssh.org
- ecdh-sha2-nistp256
- ecdh-sha2-nistp384
- ecdh-sha2-nistp521
- diffie-hellman-group-exchange-sha256
- diffie-hellman-group-exchange-sha1
- diffie-hellman-group16-sha512
- diffie-hellman-group14-sha256
- diffie-hellman-group14-sha1
- diffie-hellman-group1-sha1
Public Key Authentication
SSH.NET supports the following private key formats:
- RSA in OpenSSL PEM ("BEGIN RSA PRIVATE KEY") and ssh.com ("BEGIN SSH2 ENCRYPTED PRIVATE KEY") format
- DSA in OpenSSL PEM ("BEGIN DSA PRIVATE KEY") and ssh.com ("BEGIN SSH2 ENCRYPTED PRIVATE KEY") format
- ECDSA 256/384/521 in OpenSSL PEM format ("BEGIN EC PRIVATE KEY")
- ECDSA 256/384/521, ED25519 and RSA in OpenSSH key format ("BEGIN OPENSSH PRIVATE KEY")
Private keys can be encrypted using one of the following cipher methods:
- DES-EDE3-CBC
- DES-EDE3-CFB
- DES-CBC
- AES-128-CBC
- AES-192-CBC
- AES-256-CBC
Host Key Algorithms
SSH.NET supports the following host key algorithms:
- ssh-ed25519
- ecdsa-sha2-nistp256
- ecdsa-sha2-nistp384
- ecdsa-sha2-nistp521
- rsa-sha2-512
- rsa-sha2-256
- ssh-rsa
- ssh-dss
Message Authentication Code
SSH.NET supports the following MAC algorithms:
- hmac-sha2-256
- hmac-sha2-512
- hmac-sha1
- hmac-sha2-256-etm@openssh.com
- hmac-sha2-512-etm@openssh.com
- hmac-sha1-etm@openssh.com
Compression
SSH.NET supports the following compression algorithms:
- none (default)
- zlib@openssh.com (.NET 6 and higher)
Framework Support
SSH.NET supports the following target frameworks:
- .NETFramework 4.6.2 (and higher)
- .NET Standard 2.0 and 2.1
- .NET 6 (and higher)
Building the library
The library has no special requirements to build, other than an up-to-date .NET SDK. See also CONTRIBUTING.md.
Supporting SSH.NET
Do you or your company rely on SSH.NET in your projects? If you want to encourage us to keep on going and show us that you appreciate our work, please consider becoming a sponsor through GitHub Sponsors.