Xbase++

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 nSuccess
LOCAL oMime
LOCAL oCert
LOCAL oPrivKey
LOCAL nTransferHeaderFields

nSuccess := 0

oMime := CreateObject("Chilkat.Mime")
nSuccess := oMime:SetBodyFromPlainText("This message will be signed.")
IF (nSuccess == 0)
    ? oMime:LastErrorText
    oMime:destroy()
    RETURN
ENDIF

//  Load the certificate and its private key separately.
oCert := CreateObject("Chilkat.Cert")
nSuccess := oCert:LoadFromFile("qa_data/signer.cer")
IF (nSuccess == 0)
    ? oCert:LastErrorText
    oMime:destroy()
    oCert:destroy()
    RETURN
ENDIF

oPrivKey := CreateObject("Chilkat.PrivateKey")
nSuccess := oPrivKey:LoadPemFile("qa_data/signer_privkey.pem")
IF (nSuccess == 0)
    ? oPrivKey:LastErrorText
    oMime:destroy()
    oCert:destroy()
    oPrivKey:destroy()
    RETURN
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.
nTransferHeaderFields := 1
nSuccess := oMime:AddDetachedSignaturePk2(oCert, oPrivKey, nTransferHeaderFields)
IF (nSuccess == 0)
    ? oMime:LastErrorText
    oMime:destroy()
    oCert:destroy()
    oPrivKey:destroy()
    RETURN
ENDIF

nSuccess := oMime:SaveMime("qa_output/signed.eml")
IF (nSuccess == 0)
    ? oMime:LastErrorText
    oMime:destroy()
    oCert:destroy()
    oPrivKey:destroy()
    RETURN
ENDIF

? "Detached signature added (headers transferred)."

oMime:destroy()
oCert:destroy()
oPrivKey:destroy()