Delphi DLL

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: Boolean;
ssh: HCkSsh;
hostname: PWideChar;
port: Integer;
key: HCkSshKey;
privKeyText: PWideChar;

begin
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.

ssh := CkSsh_Create();

//  Timeouts, in milliseconds.
CkSsh_putConnectTimeoutMs(ssh,5000);
CkSsh_putReadTimeoutMs(ssh,15000);

hostname := 'ssh.example.com';
port := 22;
success := CkSsh_Connect(ssh,hostname,port);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

//  LoadText is a convenience method that reads any text file into a string.  It does not itself
//  load the key.
key := CkSshKey_Create();
privKeyText := CkSshKey__loadText(key,'qa_data/my_private_key.pem');
if (CkSshKey_getLastMethodSuccess(key) = False) then
  begin
    Memo1.Lines.Add(CkSshKey__lastErrorText(key));
    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 := CkSshKey_FromOpenSshPrivateKey(key,privKeyText);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSshKey__lastErrorText(key));
    Exit;
  end;

success := CkSsh_AuthenticatePk(ssh,'mySshLogin',key);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

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

CkSsh_Disconnect(ssh);

CkSsh_Dispose(ssh);
CkSshKey_Dispose(key);