* Timo T. Rajala <[EMAIL PROTECTED]> writes: > One difference is that the "smime-type=enveloped-data;" row is missing > from the MS mail. I inserted this row in the MS mail and opened the > mail in mutt: now both signature check and decrypt works. > > My question is: Is the MS MUA not following the S/MIME standard by > omitting this row or is mutt wrong by not being able to handle it > without this row?
I'm quoting from RFC2633: 3.2: ... Because there are several types of application/pkcs7-mime objects, a sending agent SHOULD do as much as possible to help a receiving agent know about the contents of the object without forcing the receiving agent to decode the ASN.1 for the object. The MIME headers of all application/pkcs7-mime objects SHOULD include the optional "smime- type" parameter, as described in the following sections. 3.2.1: For the application/pkcs7-mime, sending agents SHOULD emit the optional "name" parameter to the Content-Type field for compatibility with older systems. Sending agents SHOULD also emit the optional Content-Disposition field [CONTDISP] with the "filename" parameter. If a sending agent emits the above parameters, the value of the parameters SHOULD be a file name with the appropriate extension: MIME Type File Extension Application/pkcs7-mime (signedData, .p7m envelopedData) Application/pkcs7-mime (degenerate .p7c signedData "certs-only" message) Application/pkcs7-signature .p7s So this MS MUA SHOULD include "smime-type", but is not and mutt should be able to determine the MIME type from the file extension but is not. -- Timo T. Rajala
