(Visual FoxPro) Sign a Byte Array to Create an Opaque Signature in a Byte Array

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.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Cert')
loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
IF (lnSuccess = 0) THEN
    ? loCert.LastErrorText
    RELEASE loCert
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.FileAccess')
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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Crypt2')
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