Logic Apps AS2 encoding incorrectly creates a base64 MIME part without line breaks
A signed AS2 message, generated by the Logic Apps AS2 encode action, looks something like:
Content-Type: text/plain; charset=utf-8
[extremely long base64 string]
The trouble I am having is that I am trying to verify the signature of this message using OpenSSL and it is rightly rejecting it, because [extremely long base64 string] does not have line breaks as per the S/MIME standard. RFC1341 is unequivocal; it states:
The output stream (encoded bytes) must be represented in lines of no more than 76 characters each.
This is in section 5.2 Base64 Content-Transfer-Encoding
Therefore Logic Apps' generation of S/MIME signed messages is incorrect since standards-compliant S/MIME messages with base64 Content Transfer Encoding must contain line breaks.
Please create a support request if this is still an issue