GODT-213: Use application/octet-stream for encrypted parts

pkg/message/build_rfc822_custom.go

@@ -27,42 +27,7 @@ import (
 	"github.com/emersion/go-message"
 )
 
-/* writeCustomTextPart writes an armored-PGP text part for a message body that couldn't be decrypted.
-The following is an example of such a message:
-
-Mime-Version: 1.0
-Content-Type: multipart/mixed;
- boundary=d8a04ef2e12150946d27f84fc82b9e70a5e314f91a0f2190e38c7aad623466da
-Message-Id: <messageID@protonmail.internalid>
-Date: Fri, 26 Mar 2021 14:10:00 +0000
-
---d8a04ef2e12150946d27f84fc82b9e70a5e314f91a0f2190e38c7aad623466da
-Content-Type: text/plain
-
------BEGIN PGP MESSAGE-----
-Version: GopenPGP 2.1.3
-Comment: This message could not be decrypted: gopenpgp: error in reading message: openpgp: incorrect key
-
-wcBMA1iOyuyBImpHAQf/boKq75jyV5kGzl8ObcjLuaVrVEw5YbrI1M9gAb/5eq+t
-Mzd2qK0owYwBmuvYj3pk2b15miOIPfAYlbQVyIaseq/O4XchPvtJZKxh42eDcYhD
-zwqHrYxtCLOOBY6b15Aq8tVLORi4+/VCWJrTHtCdKq71UX7bvBdQRaZqOIJ+bUiP
-72IkaWjdVmCgLCmzPN3R3VKsmjTNBt1GRMc6vosQyoAeClyf94wgE1sXGsumXBQs
-MX69zK9a36Ya67PpQ9AGVR2peEF07s5O+t/PxkStWfFvMwnnOOSgdHfN0PSwkhoL
-EIwDA6lh7+2UlbX9pFi908PDl0OuoLgrL+NyleUPtdLAugGUa0U1fn6K1gwFGcsj
-DKflgAMXixhf83xpmz4fM3zzM988ecQsXozQcUDrxSTxzdfWXSaWQDWHguCiL0xM
-aPkf4kUn4RX3AoZVTC4GXvupzAQUqjJhyd0p7lJGOwIw0Ik77PxeCFNvWiZHJ3W+
-7PYuehSUgyDJJe7q1GFFcMUspnPmuvhbenKIHlKwGfptnXLRIW15sdcca2Etz5i4
-H71rHKwzAPdNHBQVvN0Nmt77RGAIy4Az8fRwz7hD7E92r4BkaaYntrQe9DUXYc50
-HVXyeFcvpfbEaK+fObxk1ljig+Io2liPx7pn/YBFytMy1mlwhjroMPjMUXuTXqje
-NHnOJVxnnXMwGh34wUIEwOmTskJoGkQjQbjvixkwNRGnLzIHuD6614pXtgTDtBzc
-AKuQssqOky1Q7KjdusMWnoVL7gTbSrIUxXoKChear5XgPzFevQhQNEfTI8DDMbYR
-La1Cc6aFtMPUShzNc3Wp3dVLM09WygEUsYZFmA==
-=00ma
------END PGP MESSAGE-----
---d8a04ef2e12150946d27f84fc82b9e70a5e314f91a0f2190e38c7aad623466da--
-
-.
-*/
+// writeCustomTextPart writes an armored-PGP text part for a message body that couldn't be decrypted.
 func writeCustomTextPart(
 	w *message.Writer,
 	msg *pmapi.Message,
@@ -113,11 +78,12 @@ func writeCustomAttachmentPart(
 		return err
 	}
 
+	filename := mime.QEncoding.Encode("utf-8", att.Name+".pgp")
+
 	var hdr message.Header
 
-	hdr.SetContentType("application/pgp-encrypted", map[string]string{"name": mime.QEncoding.Encode("utf-8", att.Name+".pgp")})
-
-	hdr.SetContentDisposition(att.Disposition, map[string]string{"filename": mime.QEncoding.Encode("utf-8", att.Name+".pgp")})
+	hdr.SetContentType("application/octet-stream", map[string]string{"name": filename})
+	hdr.SetContentDisposition(att.Disposition, map[string]string{"filename": filename})
 
 	part, err := w.CreatePart(hdr)
 	if err != nil {