B4X

Check if a MIME Entity is Signed (S/MIME)

Demonstrates the Chilkat Mime.IsSigned method, which returns whether the entity is a complete CMS/PKCS #7 signed S/MIME wrapper, including detached multipart/signed and opaque forms. It takes no arguments.

Note: The file path is relative to the application's current working directory. Absolute paths may also be used. Supply the path to your own file.

Background: Before verifying a signature you need to know one is present, and this is the check. A signed S/MIME message comes in two shapes — detached (multipart/signed, signature alongside the content) and opaque (application/pkcs7-mime, content wrapped inside the signature) — and this recognizes both. Follow a true result with Verify.

Chilkat B4X Downloads

Download Chilkat for B4X

B4X

Dim success As Boolean = False

'  Demonstrates the Mime.IsSigned method, which returns whether the entity is a complete CMS/PKCS #7 signed S/MIME wrapper.  It takes no arguments.

Dim mime As ChilkatMime
mime.Initialize
success = mime.LoadMimeFile("qa_data/signed.eml")
If success = False Then
    Log(mime.LastErrorText)
    Return
End If


If mime.IsSigned Then
    Log("This is a signed S/MIME message.")
Else
    Log("This is not a signed S/MIME message.")
End If