(Visual Basic 6.0) 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 ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

Dim crypt As New ChilkatCrypt2

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

Dim cert As New ChilkatCert
Dim success As Long
success = cert.LoadPfxFile(pfxPath,pfxPassword)
If (success <> 1) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

' Tell the crypt component to use this cert.
success = crypt.SetSigningCert(cert)
If (success <> 1) Then
    Debug.Print 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 = 1

' 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
inFile = "qa_data/json/sample.json"
Dim sigFile As String
sigFile = "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 = 0) Then
    Debug.Print crypt.LastErrorText
    Exit Sub
End If

' Verify the .p7m file and extract the original file from the .p7m. 
Dim extractedToFilePath As String
extractedToFilePath = "qa_output/sample.json"
success = crypt.VerifyP7M(sigFile,extractedToFilePath)
If (success = 0) Then
    Debug.Print crypt.LastErrorText
    Exit Sub
End If

Debug.Print "Success!"