(VB.NET) PKCS7 Encrypt using Multiple Certificates

Encrypts MIME using multiple digital certificates. Calls AddEncryptCert once per certificate, followed by a call to EncryptN. The MIME may be decrypted by any owner of one of the certificates + its associated private key.

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

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

Dim mime As New Chilkat.Mime

' Build a simple MIME message to be encrypted:
Dim success As Boolean = mime.AddHeaderField("Content-Type","text/plain")
success = mime.AddHeaderField("abc","123")
mime.SetBody("This is a test")

' A digital certificate is required to create PKCS7 encrypted MIME.
' It can come from a variety of sources: .cer file, .pfx file, PEM files,
' an in-memory representation, or directly from a Windows
' registry-based certificate store.

' Load one cert from a .cer file:
Dim cert1 As New Chilkat.Cert
success = cert1.LoadFromFile("myCert.cer")
If (success = False) Then
    Debug.WriteLine(cert1.LastErrorText)
    Exit Sub
End If


' Load another cert ...
Dim cert2 As New Chilkat.Cert
success = cert2.LoadFromFile("anotherCert.cer")
If (success = False) Then
    Debug.WriteLine(cert2.LastErrorText)
    Exit Sub
End If


' Tell the MIME object to use these certs for encrypting:
' (AddEncryptCert shouldn't fail if we already know it contains
' a valid certificate..)
success = mime.AddEncryptCert(cert1)
success = mime.AddEncryptCert(cert2)

' Encrypt the MIME:
success = mime.EncryptN()
If (success = False) Then
    Debug.WriteLine(mime.LastErrorText)
    Exit Sub
End If


' Display the MIME:
Debug.WriteLine(mime.GetMime())

' The resulting S/MIME looks something like this:

' abc: 123
' Content-Disposition: attachment; filename="smime.p7m"
' Content-Transfer-Encoding: base64
' Content-Type: application/x-pkcs7-mime;
'  name="smime.p7m"
' 
' MIID4QYJKoZIhvcNAQcDoIID0jCCA84CAQAxggNlMIIBgQIBADBpMFUxCzAJBgNVBAYTAlpBMSUw
' IwYDVQQKExxUaGF3dGUgQ29uc3VsdGluZyAoUHR5KSBMdGQuMR8wHQYDVQQDExZUaGF3dGUgQ29k
' ZSBTaWduaW5nIENBAhB4ouTcAmLszrGi170k1deSMA0GCSqGSIb3DQEBAQUABIIBAKnOPgmISrNH
' Hd+zESvH5dl5TvBLCxLuIuH6cuZdowHzCqAUzaYFdn1rp88Vvu2x3s6WOvzje/+dE1x0YjEpeqxd
' ufehlb6Jl9ucxSMWARWMxWGxu0eZGJVt+SBBrVddqdtrIU9lVt5rBxkU67P8PxgbwdNCX3qJENRO
' P/rvp5ngoCkpIxeGqSkPvWv+CA3IXS8FPs8Sl4HNPiAj3e9RBm2MxI1u4cn1HvgGg8yHgHLMG5JF
' LzGsmotSQaqEwq2JtOlkjfOwEI+ZhbWQupj6gen2aGc5sW3J26H1usxtV2TQ7WRRxqnZGmlh20dW
' 4lo3kITYI+iapGlJXmrlDYh2CjkwggHcAgEAMIHDMIGuMQswCQYDVQQGEwJVUzELMAkGA1UECBMC
' VVQxFzAVBgNVBAcTDlNhbHQgTGFrZSBDaXR5MR4wHAYDVQQKExVUaGUgVVNFUlRSVVNUIE5ldHdv
' cmsxITAfBgNVBAsTGGh0dHA6Ly93d3cudXNlcnRydXN0LmNvbTE2MDQGA1UEAxMtVVROLVVTRVJG
' aXJzdC1DbGllbnQgQXV0aGVudGljYXRpb24gYW5kIEVtYWlsAhAj50QEWUPwA+jXOiL8sMwXMA0G
' CSqGSIb3DQEBAQUABIIBAFQ1cydWC4M9tdgAlCN03kP8eyuXajwT+5ByhOcJhjuCABg7U8w4Rx28
' braGqV+TCBxjyMsqD0KcW49VT6ZHMpQ1yN8R72qDsidmfm9w3u0jVgsaaBkTJXMy4COY/3cZWmYG
' dL3Qty8uFeQYddytt6UPJpGJZYsrdFG2doe6qHiRtAxxPrd0GmQRcGvxyDdsojkoBlTMbfwaXOI3
' xepR/oh60x/3npUCsl2VpNPfo6oZoej6YZGEuz2MvuWvXVhvuqoTqXGwGDgYMxwTbPwklqZiJtsK
' r5Ep3NlWAQX8MGWL0H+NC22cqJuqUCL05yqyAv+JMCpZGAwOVb/wiVNjpAIwYAYJKoZIhvcNAQcB
' MBkGCCqGSIb3DQMCMA0CAToECA5NAJY12cU+gDgZFUc+nsQUUbiR1GH8iBVLI+XWlja9TXEe1Hzt
' NlsOylRVBDzjNxUtX/zC0YR7bs+2Cf4JbyuMOA==