Visual Basic 6.0

Sign a Byte Array to Create an Opaque Signature in a Byte Array

See more Digital Signatures Examples

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. Visual Basic 6.0

Dim success As Long
success = 0

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

Dim cert As New ChilkatCert
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."