(Visual Basic 6.0) Sign a Byte Array to Create an Opaque Signature in a Byte Array

Signs data contained in a byte array to produce an opaque signature (also in a byte array). An opaque signature is a PKCS7 signature (also known as CAdES) that embeds the signed data. Also shows how to verify the signature and extract the original data.

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

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

Dim cert As New ChilkatCert
Dim success As Long
success = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
If (success = 0) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

Dim fac As New CkFileAccess

Dim fileBytes() As Byte
fileBytes = fac.ReadEntireFile("qa_data/pdf/sample.pdf")
If (fac.LastMethodSuccess <> 1) Then
    Debug.Print fac.LastErrorText
    Exit Sub
End If

Dim crypt As New ChilkatCrypt2

success = crypt.SetSigningCert(cert)

' We can sign any type of file.

Dim sigBytes() As Byte
sigBytes = crypt.OpaqueSignBytes(fileBytes)
If (crypt.LastMethodSuccess <> 1) Then
    Debug.Print crypt.LastErrorText
    Exit Sub
End If

success = fac.WriteEntireFile("qa_output/sample.pdf.p7m",sigBytes)
If (fac.LastMethodSuccess <> 1) Then
    Debug.Print fac.LastErrorText
    Exit Sub
End If

' We can verify the opaque signature and extract the original data like this
Dim originalData() As Byte
originalData = crypt.OpaqueVerifyBytes(sigBytes)
If (crypt.LastMethodSuccess <> 1) Then
    Debug.Print crypt.LastErrorText
    Exit Sub
End If

success = fac.WriteEntireFile("qa_output/sample.pdf",originalData)
If (fac.LastMethodSuccess <> 1) Then
    Debug.Print fac.LastErrorText
    Exit Sub
End If

Debug.Print "Signature is verified and the original data was extracted."