PureBasic

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.

Chilkat PureBasic Downloads

Download Chilkat for PureBasic

PureBasic

IncludeFile "CkCert.pb"
IncludeFile "CkMime.pb"
IncludeFile "CkPrivateKey.pb"

Procedure ChilkatExample()

    success.i = 0

    mime.i = CkMime::ckCreate()
    If mime.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkMime::ckSetBodyFromPlainText(mime,"This message will be signed.")
    If success = 0
        Debug CkMime::ckLastErrorText(mime)
        CkMime::ckDispose(mime)
        ProcedureReturn
    EndIf

    ;  Load the certificate and its private key separately.
    cert.i = CkCert::ckCreate()
    If cert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkCert::ckLoadFromFile(cert,"qa_data/signer.cer")
    If success = 0
        Debug CkCert::ckLastErrorText(cert)
        CkMime::ckDispose(mime)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    privKey.i = CkPrivateKey::ckCreate()
    If privKey.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPrivateKey::ckLoadPemFile(privKey,"qa_data/signer_privkey.pem")
    If success = 0
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkMime::ckDispose(mime)
        CkCert::ckDispose(cert)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    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.
    transferHeaderFields.i = 1
    success = CkMime::ckAddDetachedSignaturePk2(mime,cert,privKey,transferHeaderFields)
    If success = 0
        Debug CkMime::ckLastErrorText(mime)
        CkMime::ckDispose(mime)
        CkCert::ckDispose(cert)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    success = CkMime::ckSaveMime(mime,"qa_output/signed.eml")
    If success = 0
        Debug CkMime::ckLastErrorText(mime)
        CkMime::ckDispose(mime)
        CkCert::ckDispose(cert)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    Debug "Detached signature added (headers transferred)."


    CkMime::ckDispose(mime)
    CkCert::ckDispose(cert)
    CkPrivateKey::ckDispose(privKey)


    ProcedureReturn
EndProcedure