(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.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

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

    var success;
    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();