(PureBasic) Sign a File to Create a .p7m File (using a PFX)

PureBasic example to sign a file creating a .p7m file as output. The .p7m contains the signed contents of the original file. It can be verified and restored by calling VerifyP7M.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkCertStore.pb"
IncludeFile "CkCert.pb"
IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

    ; This example requires the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Use a digital certificate and private key from a PFX file (.pfx or .p12).
    signingCertSubject.s = "Acme Inc"
    pfxFilename.s = "/Users/chilkat/testData/pfx/acme.pfx"
    pfxPassword.s = "test123"

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

    success.i = CkCertStore::ckLoadPfxFile(certStore,pfxFilename,pfxPassword)
    If success <> 1
        Debug CkCertStore::ckLastErrorText(certStore)
        CkCrypt2::ckDispose(crypt)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    cert.i
    cert = CkCertStore::ckFindCertBySubjectCN(certStore,signingCertSubject)
    If CkCertStore::ckLastMethodSuccess(certStore) = 0
        Debug "Failed to find certificate by subject common name."
        CkCrypt2::ckDispose(crypt)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    ; Tell the crypt component to use this cert.
    success = CkCrypt2::ckSetSigningCert(crypt,cert)

    ; We can sign any type of file, creating a .p7m as output:
    inFile.s = "/Users/chilkat/testData/pdf/sample.pdf"
    outputFile.s = "/Users/chilkat/testData/p7m/sample.pdf.p7m"
    success = CkCrypt2::ckCreateP7M(crypt,inFile,outputFile)
    If success = 0
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkCert::ckDispose(cert)

        CkCrypt2::ckDispose(crypt)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    ; Verify and restore the original file:
    success = CkCrypt2::ckSetVerifyCert(crypt,cert)

    inFile = outputFile
    outputFile = "/Users/chilkat/testData/pdf/restored.pdf"

    success = CkCrypt2::ckVerifyP7M(crypt,inFile,outputFile)
    If success = 0
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkCert::ckDispose(cert)

        CkCrypt2::ckDispose(crypt)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    CkCert::ckDispose(cert)

    Debug "Success!"


    CkCrypt2::ckDispose(crypt)
    CkCertStore::ckDispose(certStore)


    ProcedureReturn
EndProcedure