Delphi ActiveX

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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var
success: Integer;
ssh: TChilkatSsh;
hostname: WideString;
port: Integer;
key: TChilkatSshKey;
privKeyText: WideString;

begin
success := 0;

//  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.

ssh := TChilkatSsh.Create(Self);

//  Timeouts, in milliseconds.
ssh.ConnectTimeoutMs := 5000;
ssh.ReadTimeoutMs := 15000;

hostname := 'ssh.example.com';
port := 22;
success := ssh.Connect(hostname,port);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  LoadText is a convenience method that reads any text file into a string.  It does not itself
//  load the key.
key := TChilkatSshKey.Create(Self);
privKeyText := key.LoadText('qa_data/my_private_key.pem');
if (key.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(key.LastErrorText);
    Exit;
  end;

//  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 = 0) then
  begin
    Memo1.Lines.Add(key.LastErrorText);
    Exit;
  end;

success := ssh.AuthenticatePk('mySshLogin',key.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Public-key authentication successful.');

ssh.Disconnect();