PKCS7 Decrypt Using .pfx or .p12 Data

Demonstrates how to decrypt MIME using a specifc PFX file (.pfx or .p12) for the source of certificate(s) and private key(s).

Download Chilkat FileAccess ActiveX (freeware)

Download Chilkat MIME ActiveX

Dim mime As New ChilkatMime

Dim success As Long
success = mime.UnlockComponent("Anything for 30-day trial.")
If (success = 0) Then
    Text1.Text = Text1.Text & mime.LastErrorText & vbCrLf
    Exit Sub
End If

'  Load the MIME
success = mime.LoadMimeFile("encrypted.mim")
If (success = 0) Then
    Text1.Text = Text1.Text & mime.LastErrorText & vbCrLf
    Exit Sub
End If

Dim pfxData() As Byte
Dim fac As New CkFileAccess
pfxData = fac.ReadEntireFile("pfxStore/myPkcs12.p12")

Dim pfxPassword As String
pfxPassword = "myPassword"
success = mime.DecryptUsingPfxData(pfxData,pfxPassword)
If (success = 0) Then
    Text1.Text = Text1.Text & mime.LastErrorText & vbCrLf
    Exit Sub
End If

'  Display the decrypted MIME:
Text1.Text = Text1.Text & mime.GetMime() & vbCrLf

'  Note: The MIME to be decrypted should look something like this
'  when viewed in a text editor:
'  (Note that the Content-Type is application/x-pkcs7-mime)
'  
Content-Disposition: attachment; filename="smime.p7m"
Content-Transfer-Encoding: base64
Content-Type: application/x-pkcs7-mime;
 name="smime.p7m"

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