C++

SSH Public Key Authentication

Demonstrates authenticating with an SSH server using public-key authentication. A private key is loaded into an SshKey object and passed to AuthenticatePk. The matching public key must already be installed on the server for the account.

Note: The private-key path is relative to the application's current working directory. Supply the path to your own key file.

Background: Public-key authentication is the standard for unattended and automated SSH: the private key never leaves the client, the server merely trusts the corresponding public key, and no reusable password crosses the wire. SshKey imports several formats — OpenSSH PEM keys via FromOpenSshPrivateKey and PuTTY .ppk files via FromPuttyPrivateKey — encrypted or not. For an encrypted key, set the Password property before importing. Note that LoadText is only a convenience for reading a text file into a string; it does not itself load the key.

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#include <CkSsh.h>
#include <CkSshKey.h>

void ChilkatSample(void)
    {
    bool success = false;

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

    //  Demonstrates authenticating with an SSH server using public-key authentication.  The matching
    //  public key must already be installed on the SSH server for the account.

    CkSsh ssh;

    //  Timeouts, in milliseconds.
    ssh.put_ConnectTimeoutMs(5000);
    ssh.put_ReadTimeoutMs(15000);

    const char *hostname = "ssh.example.com";
    int port = 22;
    success = ssh.Connect(hostname,port);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    //  LoadText is a convenience method that reads any text file into a string.  It does not itself
    //  load the key.
    CkSshKey key;
    const char *privKeyText = key.loadText("qa_data/my_private_key.pem");
    if (key.get_LastMethodSuccess() == false) {
        std::cout << key.lastErrorText() << "\r\n";
        return;
    }

    //  Import the private key.  Both OpenSSH and PuTTY formats are supported, encrypted or not.
    //  This example loads an unencrypted OpenSSH-format key; for a PuTTY .ppk file, call
    //  FromPuttyPrivateKey instead.  For an encrypted key, set key.Password before importing.
    success = key.FromOpenSshPrivateKey(privKeyText);
    if (success == false) {
        std::cout << key.lastErrorText() << "\r\n";
        return;
    }

    success = ssh.AuthenticatePk("mySshLogin",key);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Public-key authentication successful." << "\r\n";

    ssh.Disconnect();
    }