Visual FoxPro

SFTP Authenticate with a Private Key

Demonstrates the Chilkat SFtp.AuthenticatePk method, which authenticates the connected session using public-key authentication. The first argument is the username and the second is an SshKey private key. The matching public key must already be authorized for the account on the server.

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 SFTP transfers: the private key stays on the client, the server trusts the corresponding public key, and no reusable password crosses the wire. The SshKey object imports keys in several formats — this example loads an OpenSSH private key. For an encrypted key, set its Password property before importing.

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LOCAL lnSuccess
LOCAL loSftp
LOCAL lnPort
LOCAL loPrivKey
LOCAL lcKeyText

lnSuccess = 0

*  Demonstrates the SFtp.AuthenticatePk method, which authenticates the connected session using
*  public-key authentication.  The 1st argument is the username and the 2nd is an SshKey private
*  key.  The matching public key must already be authorized for the account on the server.

loSftp = CreateObject('Chilkat.SFtp')

*  Step 1: Connect the SSH transport.  Port 22 is the usual port.
lnPort = 22
lnSuccess = loSftp.Connect("sftp.example.com",lnPort)
IF (lnSuccess = 0) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

*  Load the SSH private key.  LoadText reads the file's text, which is then imported.
loPrivKey = CreateObject('Chilkat.SshKey')
lcKeyText = loPrivKey.LoadText("qa_data/id_rsa")
IF (loPrivKey.LastMethodSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loSftp
    RELEASE loPrivKey
    CANCEL
ENDIF

lnSuccess = loPrivKey.FromOpenSshPrivateKey(lcKeyText)
IF (lnSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loSftp
    RELEASE loPrivKey
    CANCEL
ENDIF

lnSuccess = loSftp.AuthenticatePk("mySshLogin",loPrivKey)
IF (lnSuccess = 0) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    RELEASE loPrivKey
    CANCEL
ENDIF

*  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
*  file or directory operations.
lnSuccess = loSftp.InitializeSftp()
IF (lnSuccess = 0) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    RELEASE loPrivKey
    CANCEL
ENDIF

? "Authenticated with a private key."

loSftp.Disconnect()

RELEASE loSftp
RELEASE loPrivKey