(VB.NET) PKCS7 Sign Text using RSA 2048, SHA256, Base64 Output

Demonstrates how to sign text using 2048-bit RSA with SHA256, producing PKCS#7 output in Base64. The certificate w/ private key used for signing is loaded from a .p12/.pfx file.

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

Dim cert As New Chilkat.Cert

' Load the cert and private key.  Whatever the private key happens to be,
' such as RSA or ECC, then Chilkat will use it.  If the private key is 
' a 2048-bit RSA key, then that's what will be used..
Dim success As Boolean = cert.LoadPfxFile("qa_data/pfx/myCertAndKey.p12","password")
If (success <> True) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Dim crypt As New Chilkat.Crypt2

success = crypt.SetSigningCert(cert)
If (success <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


' Use SHA-256
crypt.HashAlgorithm = "sha256"

' Hash the utf-8 byte representation of the string
crypt.Charset = "utf-8"

' Return the result in base64
crypt.EncodingMode = "base64"

' Sign some text..
Dim textToSign As String = "This is the text to be hashed and signed."
Dim sigBase64 As String = crypt.OpaqueSignStringENC(textToSign)
If (crypt.LastMethodSuccess <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


Debug.WriteLine(sigBase64)

' The result:
' MIIS2wYJKoZIhvcNAQc ... zGeeY4Oxg==