PowerBuilder

A3/A4 Certificate to Create and Verify an Opaque PKCS7/CMS Signature

See more Digital Signatures Examples

Demonstrates how to use an A3 or A4 certificate w/ private key on a smartcard or token to create a PKCS7 opaque signature, and also how to verify an opaque signature.

An opaque signature is different than a detached PKCS7 signature in that it contains the original data. Verifying an opaque signature retrieves the original content.

PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Crypt
oleobject loo_Cert
string ls_OriginalData
string ls_OpaqueSig
oleobject loo_VCrypt
string ls_ExtractedData

li_Success = 0

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

loo_Crypt = create oleobject
li_rc = loo_Crypt.ConnectToNewObject("Chilkat.Crypt2")
if li_rc < 0 then
    destroy loo_Crypt
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// A certificate and private key is needed to create a signature.
// Chilkat provides many different ways to load a certificate and private key, such
// as from a smartcards and hardware tokens, PFX/.p12, Java keystore, JWK, Windows registry-based certificate stores, and other sources.
// This example will load the default certificate from the smartcard that is currently in
// the smartcard reader.

loo_Cert = create oleobject
li_rc = loo_Cert.ConnectToNewObject("Chilkat.Cert")

// If the smartcard or token requires a PIN, we can set it here to avoid the dialog...
loo_Cert.SmartCardPin = "000000"

li_Success = loo_Cert.LoadFromSmartcard("")
if li_Success <> 1 then
    Write-Debug loo_Cert.LastErrorText
    destroy loo_Crypt
    destroy loo_Cert
    return
end if

// Tell it to use the cert and private key we've loaded.
li_Success = loo_Crypt.SetSigningCert(loo_Cert)
if li_Success <> 1 then
    Write-Debug loo_Crypt.LastErrorText
    destroy loo_Crypt
    destroy loo_Cert
    return
end if

// Indicate we want the opaque signature in base64 format:
loo_Crypt.EncodingMode = "base64"

// Sign the string using the "utf-8" byte representation:
loo_Crypt.Charset = "utf-8"

// Create the opaque signature:
ls_OriginalData = "This is the string to be signed."
ls_OpaqueSig = loo_Crypt.OpaqueSignStringENC(ls_OriginalData)
if loo_Crypt.LastMethodSuccess <> 1 then
    Write-Debug loo_Crypt.LastErrorText
    destroy loo_Crypt
    destroy loo_Cert
    return
end if

Write-Debug ls_OpaqueSig

// The output looks like this:
// MIIPgQYJKoZIhvcNAQcCoIIPcjCCD24CAQExCzAJBgUrDgMCGgUAMC8GCSqGSIb3DQEHAaAiBCBUaGlzIGlzIHRoZSBzdHJpbmcgdG8gYmUgc...

// ----------------------------------------------------------------------------------------------
// Now let's verify the signature and retrieve the original data.
// We'll use a new Crypt2 object to keep things completely separate...

loo_VCrypt = create oleobject
li_rc = loo_VCrypt.ConnectToNewObject("Chilkat.Crypt2")

// We only need the certificate to verify a signature (and extract the data from
// an opaque signature).  The public key is always embedded within a certificate.
li_Success = loo_VCrypt.SetVerifyCert(loo_Cert)
if li_Success <> 1 then
    Write-Debug loo_VCrypt.LastErrorText
    destroy loo_Crypt
    destroy loo_Cert
    destroy loo_VCrypt
    return
end if

loo_VCrypt.EncodingMode = "base64"
loo_VCrypt.Charset = "utf-8"

ls_ExtractedData = loo_VCrypt.OpaqueVerifyStringENC(ls_OpaqueSig)
if loo_VCrypt.LastMethodSuccess <> 1 then
    Write-Debug loo_VCrypt.LastErrorText
    destroy loo_Crypt
    destroy loo_Cert
    destroy loo_VCrypt
    return
end if

Write-Debug "The extracted data: " + ls_ExtractedData

// The output is:
// The extracted data: This is the string to be signed.


destroy loo_Crypt
destroy loo_Cert
destroy loo_VCrypt