Sign a File to Create a .p7s (Detached Signature)

Visual FoxPro example to create a detached signature file (.p7s) for any type file. The signature can be verified by calling VerifyP7S and passing the original filename and the .p7s filename.

Download Chilkat Crypt ActiveX

LOCAL loCrypt
LOCAL lnSuccess
LOCAL lcSigningCertSubject
LOCAL lcPfxFilename
LOCAL lcPfxPassword
LOCAL loCertStore
LOCAL loCert
LOCAL lcInFile
LOCAL lcSigFile

loCrypt = CreateObject('Chilkat.Crypt2')

*  Any string argument automatically begins the 30-day trial.

lnSuccess = loCrypt.UnlockComponent("30-day trial")
IF (lnSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    QUIT
ENDIF

*  Use a digital certificate and private key from a PFX file (.pfx or .p12).

lcSigningCertSubject = "Acme Inc"

lcPfxFilename = "/Users/chilkat/testData/pfx/acme.pfx"

lcPfxPassword = "test123"

loCertStore = CreateObject('Chilkat.CertStore')
lnSuccess = loCertStore.LoadPfxFile(lcPfxFilename,lcPfxPassword)
IF (lnSuccess <> 1) THEN
    ? loCertStore.LastErrorText
    QUIT
ENDIF

loCert = loCertStore.FindCertBySubjectCN(lcSigningCertSubject)
IF (loCert = NULL ) THEN
    ? "Failed to find certificate by subject common name."
    QUIT
ENDIF

*  Tell the crypt component to use this cert.
loCrypt.SetSigningCert(loCert)

*  We can sign any type of file, creating a .p7s as output:

lcInFile = "/Users/chilkat/testData/pdf/sample.pdf"

lcSigFile = "/Users/chilkat/testData/p7s/sample.p7s"

lnSuccess = loCrypt.CreateP7S(lcInFile,lcSigFile)
IF (lnSuccess = 0) THEN
    ? loCrypt.LastErrorText
    RELEASE loCert
    QUIT
ENDIF

lnSuccess = loCrypt.VerifyP7S(lcInFile,lcSigFile)
IF (lnSuccess = 0) THEN
    ? loCrypt.LastErrorText
    RELEASE loCert
    QUIT
ENDIF

RELEASE loCert

=MESSAGEBOX("Success!")