(Excel) 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.

Download Excel Class Modules Chilkat Excel Class Modules

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

Dim crypt As Chilkat.Crypt2
Set crypt = Chilkat.NewCrypt2

' 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.
Dim cert As Chilkat.Cert
Set cert = Chilkat.NewCert


pfxPath = "qa_data/pfx/myCertAndKey.p12"

pfxPassword = "test123"


success = cert.LoadPfxFile(pfxPath,pfxPassword)
If (success <> True) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

success = crypt.SetSigningCert(cert)

' Use SHA-256 rather than the default of SHA-1
crypt.HashAlgorithm = "sha256"

' Create JSON that tells Chilkat what signing attributes to include:
Dim attrs As Chilkat.JsonObject
Set attrs = Chilkat.NewJsonObject
success = attrs.UpdateBool("contentType",True)
success = attrs.UpdateBool("signingTime",True)
success = attrs.UpdateBool("messageDigest",True)
success = attrs.UpdateBool("signingCertificateV2",True)

' 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.
success = attrs.UpdateBool("timestampToken.enabled",True)
success = attrs.UpdateString("timestampToken.tsaUrl","https://freetsa.org/tsr")
success = attrs.UpdateBool("timestampToken.addNonce",False)
success = attrs.UpdateBool("timestampToken.requestTsaCert",True)
success = attrs.UpdateString("timestampToken.hashAlg","sha256")

crypt.SigningAttributes = attrs.Emit()


inFile = "qa_data/json/sample.json"

outFile = "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.
success = crypt.CreateP7M(inFile,outFile)
If (success <> True) Then
    Debug.Print crypt.LastErrorText
    Exit Sub
End If

Debug.Print "Success."