Visual FoxPro

Sign a Byte Array to Create an Opaque Signature in a Byte Array

See more Digital Signatures Examples

Signs data contained in a byte array to produce an opaque signature (also in a byte array). An opaque signature is a PKCS7 signature (also known as CAdES) that embeds the signed data. Also shows how to verify the signature and extract the original data. Visual FoxPro

LOCAL lnSuccess
LOCAL loCert
LOCAL loFac
LOCAL loFileBytes
LOCAL loCrypt
LOCAL loSigBytes
LOCAL loOriginalData

lnSuccess = 0

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

loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
IF (lnSuccess = 0) THEN
    ? loCert.LastErrorText
    RELEASE loCert
    CANCEL
ENDIF

loFac = CreateObject('Chilkat.FileAccess')

loFileBytes = loFac.ReadEntireFile("qa_data/pdf/sample.pdf")
IF (loFac.LastMethodSuccess <> 1) THEN
    ? loFac.LastErrorText
    RELEASE loCert
    RELEASE loFac
    CANCEL
ENDIF

loCrypt = CreateObject('Chilkat.Crypt2')

lnSuccess = loCrypt.SetSigningCert(loCert)

* We can sign any type of file.

loSigBytes = loCrypt.OpaqueSignBytes(loFileBytes)
IF (loCrypt.LastMethodSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loCert
    RELEASE loFac
    RELEASE loCrypt
    CANCEL
ENDIF

lnSuccess = loFac.WriteEntireFile("qa_output/sample.pdf.p7m",loSigBytes)
IF (loFac.LastMethodSuccess <> 1) THEN
    ? loFac.LastErrorText
    RELEASE loCert
    RELEASE loFac
    RELEASE loCrypt
    CANCEL
ENDIF

* We can verify the opaque signature and extract the original data like this

loOriginalData = loCrypt.OpaqueVerifyBytes(loSigBytes)
IF (loCrypt.LastMethodSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loCert
    RELEASE loFac
    RELEASE loCrypt
    CANCEL
ENDIF

lnSuccess = loFac.WriteEntireFile("qa_output/sample.pdf",loOriginalData)
IF (loFac.LastMethodSuccess <> 1) THEN
    ? loFac.LastErrorText
    RELEASE loCert
    RELEASE loFac
    RELEASE loCrypt
    CANCEL
ENDIF

? "Signature is verified and the original data was extracted."

RELEASE loCert
RELEASE loFac
RELEASE loCrypt