(VB.NET) CAdES BES Attached (Opaque) Signature

Demonstrates how to create a CAdES BES attached signature file (.p7m). This is a PKCS7 signature format (known as an opaque, or "attached" signature) where the file data is embedded within the signature file. The signature verification both verifies the signature and extracts the original data.

(A "detached" signature is where the original data is NOT included within the PKCS7 signature format.)

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

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

Dim crypt As New Chilkat.Crypt2


' Use a digital certificate and private key from a PFX file (.pfx or .p12).
Dim pfxPath As String = "qa_data/pfx/myCertAndPrivateKey.p12"
Dim pfxPassword As String = "password"

Dim cert As New Chilkat.Cert
Dim success As Boolean = cert.LoadPfxFile(pfxPath,pfxPassword)
If (success <> True) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


' Tell the crypt component to use this cert.
success = crypt.SetSigningCert(cert)
If (success <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


' The CadesEnabled property applies to all methods that create PKCS7 signatures. 
' To create a CAdES-BES signature, set this property equal to true. 
crypt.CadesEnabled = True

' To sign with SHA1, set the HashAlgorithm property to "sha1"
crypt.HashAlgorithm = "sha1"

' To sign with SHA256, set the HashAlgorithm property to "SHA256".
crypt.HashAlgorithm = "sha256"

' Other hash algorithm choices are "md5", "md2", "sha384", and "sha512"

' We can sign any type of file, creating a .p7m as output.
' The .p7m contains the signature and also embeds the data of the file that is signed.
Dim inFile As String = "qa_data/json/sample.json"
Dim sigFile As String = "qa_output/signature.p7m"

' -----------------------------------------------------------------------------------------
' Also see Chilkat's online tool to examine a .p7m and generate code to duplicate the .p7m
' -----------------------------------------------------------------------------------------

' Create the CAdES-BES attached signature, which contains the original data.
success = crypt.CreateP7M(inFile,sigFile)
If (success = False) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


' Verify the .p7m file and extract the original file from the .p7m. 
Dim extractedToFilePath As String = "qa_output/sample.json"
success = crypt.VerifyP7M(sigFile,extractedToFilePath)
If (success = False) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Success!")