(Visual FoxPro) Sign String to create a CAdES-T Signature

This example will sign a string to create a CAdEST-T signature.

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 lnSuccess
LOCAL loAttrs
LOCAL lcStrToSign
LOCAL loBd

* 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 the certificate + private key currently inserted into a smartcard reader.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Cert')
loCert = CreateObject('Chilkat.Cert')

* If we wish to provide the smartcard PIN (otherwise the user will be prompted by the operating system).
loCert.SmartCardPin = "000000"
lnSuccess = loCert.LoadFromSmartcard("")
IF (lnSuccess <> 1) THEN
    ? loCert.LastErrorText
    RELEASE loCrypt
    RELEASE loCert
    CANCEL
ENDIF

* Note: It is also possible to use certs from .pfx/.p12, .pem, or other sources such as 
* pre-installed Windows certificates.

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()

lcStrToSign = "THIS IS MY ID"

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.BinData')
loBd = CreateObject('Chilkat.BinData')
loBd.AppendString(lcStrToSign,"utf-8")

* This creates the CAdES-T signature.  During the signature creation, it
* communicates with the TSA to get a timestampToken.
* The contents of bd are signed and replaced with the CAdES-T signature (which embeds the original content).
lnSuccess = loCrypt.OpaqueSignBd(loBd)
IF (lnSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loCrypt
    RELEASE loCert
    RELEASE loAttrs
    RELEASE loBd
    CANCEL
ENDIF

* Get the signature in base64 format:
? loBd.GetEncoded("base64_mime")

* Or save the signature to a file.
loBd.WriteFile("qa_output/cades-t_sample.p7m")

? "Success."

RELEASE loCrypt
RELEASE loCert
RELEASE loAttrs
RELEASE loBd