(Visual FoxPro) Create a CAdES-T Signature

Demonstrates how to create a signature with an external timestamp that certifies the time of signing. This requires an online TSA (Time Stamping Authority) service that is capable of producing RFC 3161 compliant timestamps.

Note: This example requires Chilkat v9.5.0.78 or greater.

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

LOCAL loCrypt
LOCAL loCert
LOCAL lcPfxPath
LOCAL lcPfxPassword
LOCAL lnSuccess
LOCAL loAttrs
LOCAL lcInFile
LOCAL lcOutFile

* 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.Crypt2')
loCrypt = CreateObject('Chilkat.Crypt2')

* This example will use a certificate + private key from a .pfx/.p12 file.
* On Windows systems, it is also possible to use certs on smartcards/usb tokens or certs pre-installed in the Windows registry.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Cert')
loCert = CreateObject('Chilkat.Cert')

lcPfxPath = "qa_data/pfx/myCertAndKey.p12"
lcPfxPassword = "test123"

lnSuccess = loCert.LoadPfxFile(lcPfxPath,lcPfxPassword)
IF (lnSuccess <> 1) THEN
    ? loCert.LastErrorText
    RELEASE loCrypt
    RELEASE loCert
    CANCEL
ENDIF

lnSuccess = loCrypt.SetSigningCert(loCert)

* Use SHA-256 rather than the default of SHA-1
loCrypt.HashAlgorithm = "sha256"

* Create JSON that tells Chilkat what signing attributes to include:
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loAttrs = CreateObject('Chilkat.JsonObject')
loAttrs.UpdateBool("contentType",1)
loAttrs.UpdateBool("signingTime",1)
loAttrs.UpdateBool("messageDigest",1)
loAttrs.UpdateBool("signingCertificateV2",1)

* A CAdES-T signature is one that includes a timestampToken created by an online TSA (time stamping authority).
* We must include the TSA's URL, as well as a few options to indicate what is desired.
* Except for the TSA URL, the options shown here are typically what you would need.
loAttrs.UpdateBool("timestampToken.enabled",1)
loAttrs.UpdateString("timestampToken.tsaUrl","https://freetsa.org/tsr")
loAttrs.UpdateBool("timestampToken.addNonce",0)
loAttrs.UpdateBool("timestampToken.requestTsaCert",1)
loAttrs.UpdateString("timestampToken.hashAlg","sha256")

loCrypt.SigningAttributes = loAttrs.Emit()

lcInFile = "qa_data/json/sample.json"
lcOutFile = "qa_output/sample_cades_t.p7m"

* This creates the CAdES-T signature.  During the signature creation, it
* communicates with the TSA to get a timestampToken.
lnSuccess = loCrypt.CreateP7M(lcInFile,lcOutFile)
IF (lnSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loCrypt
    RELEASE loCert
    RELEASE loAttrs
    CANCEL
ENDIF

? "Success."

RELEASE loCrypt
RELEASE loCert
RELEASE loAttrs