(Excel) 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.

Download Excel Class Modules Chilkat Excel Class Modules

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

Dim cert As Chilkat.Cert
Set cert = Chilkat.NewCert

' 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..

success = cert.LoadPfxFile("qa_data/pfx/myCertAndKey.p12","password")
If (success <> True) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

Dim crypt As Chilkat.Crypt2
Set crypt = Chilkat.NewCrypt2

success = crypt.SetSigningCert(cert)
If (success <> True) Then
    Debug.Print 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..

textToSign = "This is the text to be hashed and signed."

sigBase64 = crypt.OpaqueSignStringENC(textToSign)
If (crypt.LastMethodSuccess <> True) Then
    Debug.Print crypt.LastErrorText
    Exit Sub
End If

Debug.Print sigBase64

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