Visual FoxPro

Add a Detached Signature (Separate Key, Header Control)

Demonstrates the Chilkat Mime.AddDetachedSignaturePk2 method, which creates a detached signature with a separately supplied certificate and private key, and a third argument controlling transfer of the existing message header fields to the new outer entity.

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: This combines the two variations — certificate and key supplied separately, plus explicit header placement — for the case that needs both. It is the most flexible of the detached-signature methods; choose it when your key material is separate and you also care about where the message headers end up on the signed result.

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LOCAL lnSuccess
LOCAL loMime
LOCAL loCert
LOCAL loPrivKey
LOCAL lnTransferHeaderFields

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 with separately supplied cert and private key, where the 3rd
*  argument controls whether the existing message header fields are transferred to the new outer
*  multipart/signed entity.
lnTransferHeaderFields = 1
lnSuccess = loMime.AddDetachedSignaturePk2(loCert,loPrivKey,lnTransferHeaderFields)
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 (headers transferred)."

RELEASE loMime
RELEASE loCert
RELEASE loPrivKey