B4X

Convert a MIME Part's ASN.1 Body to XML

Demonstrates the Chilkat Mime.AsnBodyToXml method, which parses the current part's decoded body as ASN.1 DER and returns an XML representation of the ASN.1 structure. It takes no arguments.

Tip: Code to parse the returned XML can be generated at Chilkat Tools.

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: ASN.1 DER is the binary encoding behind PKCS #7/CMS structures — the signatures and encrypted blobs in S/MIME — and it is opaque to the naked eye. Rendering it as XML exposes the nested structure (content types, certificates, signer info) so you can inspect exactly what a signature or encrypted part contains. It is primarily a diagnostic and learning tool.

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Dim success As Boolean = False

'  Demonstrates the Mime.AsnBodyToXml method, which parses the current part's decoded body as
'  ASN.1 DER and returns an XML representation of the ASN.1 structure.  It takes no arguments.
'  This is primarily useful for inspecting binary ASN.1 content such as PKCS #7 structures.

Dim mime As ChilkatMime
mime.Initialize
success = mime.LoadMimeFile("qa_data/pkcs7_part.p7m")
If success = False Then
    Log(mime.LastErrorText)
    Return
End If


Dim asnXml As String = mime.AsnBodyToXml
If mime.LastMethodSuccess = False Then
    Log(mime.LastErrorText)
    Return
End If

Log(asnXml)
'  Code to parse this XML can be generated at Chilkat's online tool:
'  https://tools.chilkat.io/xmlParse