C#

SSH Tunnel Set Allowed Algorithms

See more SSH Tunnel Examples

Demonstrates how to explicitly set the algorithms allowed in the SSH connection protocol for SSH tunneling.

Note: This example requires Chilkat v9.5.0.99 or greater.

C#

bool success = false;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

Chilkat.SshTunnel ssh_tunnel = new Chilkat.SshTunnel();

Chilkat.JsonObject json = new Chilkat.JsonObject();

//  Here are the algorithms supported by Chilkat at the time this example was written (14-June-2024)

//  ---------------------------
//  SSH Key-Exchange Algorithms
//  ---------------------------
//  curve25519-sha256
//  curve25519-sha256@libssh.org
//  ecdh-sha2-nistp256
//  ecdh-sha2-nistp384
//  ecdh-sha2-nistp521
//  diffie-hellman-group14-sha256
//  diffie-hellman-group16-sha512
//  diffie-hellman-group18-sha512
//  diffie-hellman-group-exchange-sha256
//  diffie-hellman-group1-sha1
//  diffie-hellman-group14-sha1
//  diffie-hellman-group-exchange-sha1

//  ---------------------------
//  SSH Host Key Algorithms
//  ---------------------------
//  ssh-ed25519
//  ecdsa-sha2-nistp256
//  ecdsa-sha2-nistp384
//  ecdsa-sha2-nistp521
//  rsa-sha2-256
//  rsa-sha2-512
//  ssh-rsa
//  ssh-dss

//  ---------------------------
//  SSH Cipher Algorithms
//  ---------------------------
//  chacha20-poly1305@openssh.com
//  aes128-ctr
//  aes256-ctr
//  aes192-ctr
//  aes128-cbc
//  aes256-cbc
//  aes192-cbc
//  aes128-gcm@openssh.com
//  aes256-gcm@openssh.com
//  twofish256-cbc
//  twofish128-cbc
//  blowfish-cbc

//  ---------------------------
//  SSH MAC Algorithms
//  ---------------------------
//  hmac-sha2-256
//  hmac-sha2-512
//  hmac-sha2-256-etm@openssh.com
//  hmac-sha2-512-etm@openssh.com
//  hmac-sha1-etm@openssh.com
//  hmac-sha1
//  hmac-ripemd160
//  hmac-sha1-96
//  hmac-md5

//  Specify the allowed key-exchange, host-key, cipher (i.e. encryption), and mac (i.e. hash) algorithms allowed, in the order of preference.
//  -------------------------------------------------------------------------------------------------------------------------------------------
//  Note: You typically should NOT explicitly set allowed algorithms.
//  By default, Chilkat orders algorithms according to best practices, and pays attention to vulnerabilities such as the "Terrapin Attack".
//  Hard-coding algorthims can make your application brittle and prone to breaking over a long period of time,
//  if a server (at some point in the future) changes its allowed algorithms, or if you connect to a different server,
//  such that the client (Chilkat) and server cannot find a set of mutually agreed-upon algorithms.
//  -------------------------------------------------------------------------------------------------------------------------------------------
string allowed_kex = "curve25519-sha256@libssh.org,ecdh-sha2-nistp256";
string allowed_hostKey = "ssh-ed25519,ecdsa-sha2-nistp256";
string allowed_cipher = "chacha20-poly1305@openssh.com,aes256-ctr";
string allowed_mac = "hmac-sha2-256,hmac-sha2-512";

json.UpdateString("kex",allowed_kex);
json.UpdateString("hostKey",allowed_hostKey);
json.UpdateString("cipher",allowed_cipher);
json.UpdateString("mac",allowed_mac);
ssh_tunnel.SetAllowedAlgorithms(json);

int port = 22;
success = ssh_tunnel.Connect("example.com",port);
if (success != true) {
    Debug.WriteLine(ssh_tunnel.LastErrorText);
    return;
}

Debug.WriteLine("Connected.");

//  ....
//  ....