VB.NET

Sign a Byte Array to Create a Detached Signature in a Byte Array

See more Digital Signatures Examples

Signs data contained in a byte array to produce a detached signature (also in a byte array). Also shows how to verify the signature. VB.NET

Dim success As Boolean = False

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

Dim cert As New Chilkat.Cert
success = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Dim fac As New Chilkat.FileAccess

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


Dim crypt As New Chilkat.Crypt2

success = crypt.SetSigningCert(cert)

' We can sign any type of file.
' The result is a detached signature (a signature that does not contain the data being signed).

Dim sigBytes() As Byte
sigBytes = crypt.SignBytes(fileBytes)
If (crypt.LastMethodSuccess <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


success = fac.WriteEntireFile("qa_output/sample.pdf.p7s",sigBytes)
If (fac.LastMethodSuccess <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If


' We can verify the detached signature like this
Dim verified As Boolean = crypt.VerifyBytes(fileBytes,sigBytes)
If (crypt.LastMethodSuccess <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Verified = " & verified)