Node.js

SSH Set Allowed Algorithms

See more SSH Examples

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

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

Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

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

    var ssh = new chilkat.Ssh();

    var 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.
    //  -------------------------------------------------------------------------------------------------------------------------------------------
    var allowed_kex = "curve25519-sha256@libssh.org,ecdh-sha2-nistp256";
    var allowed_hostKey = "ssh-ed25519,ecdsa-sha2-nistp256";
    var allowed_cipher = "chacha20-poly1305@openssh.com,aes256-ctr";
    var 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.SetAllowedAlgorithms(json);

    var port = 22;
    success = ssh.Connect("example.com",port);
    if (success !== true) {
        console.log(ssh.LastErrorText);
        return;
    }

    console.log("Connected.");

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

}

chilkatExample();