B4X

Sign String to create a CAdES-T Signature

See more CAdES Examples

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

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

B4X

Dim success As Boolean = False

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

Dim crypt As ChilkatCrypt2
crypt.Initialize("crypt")

'  This example will use the certificate + private key currently inserted into a smartcard reader.
Dim cert As ChilkatCert
cert.Initialize("cert")

'  If we wish to provide the smartcard PIN (otherwise the user will be prompted by the operating system).
cert.SmartCardPin = "000000"
success = cert.LoadFromSmartcard("")
If success <> True Then
    Log(cert.LastErrorText)
    Return
End If


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

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 ChilkatJsonObject
attrs.Initialize
attrs.UpdateBool("contentType", True)
attrs.UpdateBool("signingTime", True)
attrs.UpdateBool("messageDigest", True)
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.
attrs.UpdateBool("timestampToken.enabled", True)
attrs.UpdateString("timestampToken.tsaUrl", "https://freetsa.org/tsr")
attrs.UpdateBool("timestampToken.addNonce", False)
attrs.UpdateBool("timestampToken.requestTsaCert", True)
attrs.UpdateString("timestampToken.hashAlg", "sha256")

crypt.SigningAttributes = attrs.Emit

Dim strToSign As String = "THIS IS MY ID"

Dim bd As ChilkatBinData
bd.Initialize
bd.AppendString(strToSign, "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).
success = crypt.OpaqueSignBd(bd)
If success <> True Then
    Log(crypt.LastErrorText)
    Return
End If


'  Get the signature in base64 format:
Log(bd.GetEncoded("base64_mime"))

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

Log("Success.")