VBScript

Decrypt S/MIME using Added Credential Sources

Loads a CMS/PKCS #7 encrypted S/MIME message and decrypts it back to the original MIME content.

The recipient's certificate and private key are supplied from a PFX added with AddPfxSourceFile, and Decrypt automatically selects the matching private key based on the CMS recipient information.

The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background. Decrypt requires access to the recipient's private key. Chilkat matches the encrypted message's recipient identifiers against the certificates and keys made available through sources such as AddPfxSourceFile, AddDecryptCert, or a certificate vault.

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VBScript

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

success = 0

set mime = CreateObject("Chilkat.Mime")
success = mime.LoadMimeFile("qa_data/encrypted.eml")
If (success = 0) Then
    outFile.WriteLine(mime.LastErrorText)
    WScript.Quit
End If

'  Load the recipient's certificate and private key (from a PFX) so decryption can find them.  The
'  PFX password should come from a secure source rather than being hard-coded.
pfxPassword = "myPfxPassword"
success = mime.AddPfxSourceFile("qa_data/recipient.pfx",pfxPassword)
If (success = 0) Then
    outFile.WriteLine(mime.LastErrorText)
    WScript.Quit
End If

'  Decrypt.  Chilkat identifies the correct recipient from the CMS recipient info and uses the
'  matching private key from the added sources.
success = mime.Decrypt()
If (success = 0) Then
    outFile.WriteLine(mime.LastErrorText)
    WScript.Quit
End If

body = mime.GetBodyDecoded()
If (mime.LastMethodSuccess = 0) Then
    outFile.WriteLine(mime.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine(body)

outFile.Close