Visual FoxPro

Add a Detached Signature with a Separate Private Key

Demonstrates the Chilkat Mime.AddDetachedSignaturePk method, which creates a detached signature using a signer certificate and its separately supplied private key. The first argument is the Cert and the second is the PrivateKey.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Sometimes the certificate and its private key live apart — a .cer alongside a PEM key file, for instance — rather than bundled in a single PFX. This method pairs them explicitly for signing, whereas AddDetachedSignature expects a Cert that already provides its key. The result is the same multipart/signed message.

Chilkat Visual FoxPro Downloads

Download Chilkat for Visual FoxPro

Visual FoxPro

LOCAL lnSuccess
LOCAL loMime
LOCAL loCert
LOCAL loPrivKey

lnSuccess = 0

loMime = CreateObject('Chilkat.Mime')
lnSuccess = loMime.SetBodyFromPlainText("This message will be signed.")
IF (lnSuccess = 0) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    CANCEL
ENDIF

*  Load the certificate and its private key separately.
loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadFromFile("qa_data/signer.cer")
IF (lnSuccess = 0) THEN
    ? loCert.LastErrorText
    RELEASE loMime
    RELEASE loCert
    CANCEL
ENDIF

loPrivKey = CreateObject('Chilkat.PrivateKey')
lnSuccess = loPrivKey.LoadPemFile("qa_data/signer_privkey.pem")
IF (lnSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loMime
    RELEASE loCert
    RELEASE loPrivKey
    CANCEL
ENDIF

*  Create a detached signature when the certificate and private key are supplied separately.  The
*  1st argument is the signer certificate and the 2nd is its private key.
lnSuccess = loMime.AddDetachedSignaturePk(loCert,loPrivKey)
IF (lnSuccess = 0) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    RELEASE loCert
    RELEASE loPrivKey
    CANCEL
ENDIF

lnSuccess = loMime.SaveMime("qa_output/signed.eml")
IF (lnSuccess = 0) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    RELEASE loCert
    RELEASE loPrivKey
    CANCEL
ENDIF

? "Detached signature added."

RELEASE loMime
RELEASE loCert
RELEASE loPrivKey