c# - Mimekit causing bad data when decrypting an email -

i have email application creates encrypted emails. works fine in outlook , email counterparties send email reports no issues. when try decrypt them mimekit "bad data" exception.

some of stack trace:

at system.security.cryptography.pkcs.envelopedcms.decryptcontent(recipientinfocollection recipientinfos, x509certificate2collection extrastore)    @ system.security.cryptography.pkcs.envelopedcms.decrypt() @ mimekit.cryptography.windowssecure... 

my email mime looks this:

received: dx ([x])  x ([x]) mapi id  x; fri, 7 mar 2014 14:48:49 +0100 from: x <x@x.com> to: x <x2@x.com> subject:  xxxxxxxx  07-03-2014 14:48:46 thread-topic:  xxxxxxx  07-03-2014 14:48:46 thread-index: aqhpogv3jhiue6wujk+equ4eaa1oda== date: fri, 7 mar 2014 14:48:48 +0100 message-id: <x> accept-language: da-dk, en-us content-language: en-us x-ms-exchange-organization-authas: x x-ms-exchange-organization-authmechanism: x x-ms-exchange-organization-authsource: x x-ms-has-attach: yes x-ms-exchange-organization-scl: -1 x-ms-tnef-correlator: content-type: application/pkcs7-mime; name="smime.p7m";     smime-type=enveloped-data content-disposition: attachment; filename="smime.p7m" content-transfer-encoding: base64 mime-version: 1.0  miieogyjkozihvcnaqcdoiiekzcchiccaqaxgglnmiic4wibadcbyjcbxdefmb0ga1uechmwrgfu c2tlienvbw1vzgl0awvzieevuzeambgga1uecxmrqnvzaw5lc3mgu29mdhdhcmuxntazbgkqhkig 9w0bcqewjmj1c2luzxnzy2xlyxjpbmdazgfuc2tly29tbw9kaxrpzxmuy29tmq8wdqydvqqhewzb 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this how perform encryption:

public static string encryptcontent(string content, x509certificate2 certificate) {     byte[] contentbytes = encoding.ascii.getbytes(content);      var envelopedcms = new envelopedcms(subjectidentifiertype.issuerandserialnumber, new contentinfo(contentbytes));     var recipient = new cmsrecipient(subjectidentifiertype.issuerandserialnumber, certificate);      envelopedcms.encrypt(recipient);     var encodeddata = envelopedcms.encode();     var encodeddatabase64 = convert.tobase64string(encodeddata, base64formattingoptions.insertlinebreaks);      return encodeddatabase64; } 

and how attempt decrypt:

var primarysecuremimecontext = createsecuremimecontext(certificateinfo.primarycertificate,                                                                    certificateinfo.primarypassword);             var primarydecryptedentity = entity.decrypt(primarysecuremimecontext);   private securemimecontext createsecuremimecontext(string certificatefilename, string certificatepassword)     {         var securemimecontext = new windowssecuremimecontext();         var certificate = new x509certificate2(certificatefilename,                                                certificatepassword);         var bouncyx509certificate = org.bouncycastle.security.dotnetutilities.fromx509certificate(certificate);         securemimecontext.import(bouncyx509certificate);         return securemimecontext;     } 

when decrypt content myself using enveloped cms directly, there no issues.

this email after own decryption:

content-type: multipart/mixed;     boundary="5511bd79-26dc-41e5-ac96-7adfdea5f6e5"  --5511bd79-26dc-41e5-ac96-7adfdea5f6e5 content-type: text/plain; charset="us-ascii" content-transfer-encoding: quoted-printable   --5511bd79-26dc-41e5-ac96-7adfdea5f6e5 content-type: application/octet-stream;     name="testfile.txt" content-transfer-encoding: base64 content-disposition: attachment;     filename="testfile.txt"  77u/vgvlzwvlzxn0 --5511bd79-26dc-41e5-ac96-7adfdea5f6e5-- 

can see causing this?

after having using dummysecuremimecontext proposed jstedfast works. more thorough walkthrough can found here: https://github.com/jstedfast/mimekit/issues/38

i think problem way adding certificate context:

private securemimecontext createsecuremimecontext(string certificatefilename, string certificatepassword) {     var securemimecontext = new windowssecuremimecontext();     var certificate = new x509certificate2(certificatefilename,                                            certificatepassword);     var bouncyx509certificate = org.bouncycastle.security.dotnetutilities.fromx509certificate(certificate);     securemimecontext.import(bouncyx509certificate);     return securemimecontext; } 

what doing adding certificate addressbook certificate store, want add in order decrypt (because you'll need private key password well) personal cert store.

try this:

private securemimecontext createsecuremimecontext (string certificatefilename, string certificatepassword) {     var securemimecontext = new windowssecuremimecontext ();      using (var stream = file.openread (certificatefilename))         securemimecontext.import (stream, certificatepassword);      return securemimecontext; } 

the exception message getting isn't helpful, guessing means can't find certificate and/or private key. wrote test program , have been unsuccessful in reproducing bug, wrong... since certificates/private keys imported personal cert store, i'm not sure how remove them test theory.

let me know how works out you.

update: oops, done goofed. updated createsecuremimecontext() above open certificate file stream because windowssecuremimecontext.import() takes stream, not file name.