diff --git a/k9mail/src/main/java/com/fsck/k9/crypto/MessageCryptoStructureDetector.java b/k9mail/src/main/java/com/fsck/k9/crypto/MessageCryptoStructureDetector.java
index 974811957..cd8bd7034 100644
--- a/k9mail/src/main/java/com/fsck/k9/crypto/MessageCryptoStructureDetector.java
+++ b/k9mail/src/main/java/com/fsck/k9/crypto/MessageCryptoStructureDetector.java
@@ -233,7 +233,7 @@ public class MessageCryptoStructureDetector {
         return dataUnavailable || protocolMatches;
     }
 
-    private static boolean isPartMultipartEncrypted(Part part) {
+    public static boolean isPartMultipartEncrypted(Part part) {
         if (!isSameMimeType(part.getMimeType(), MULTIPART_ENCRYPTED)) {
             return false;
         }
diff --git a/k9mail/src/main/java/com/fsck/k9/mailstore/MessageViewInfoExtractor.java b/k9mail/src/main/java/com/fsck/k9/mailstore/MessageViewInfoExtractor.java
index a51ddff2d..feeb06946 100644
--- a/k9mail/src/main/java/com/fsck/k9/mailstore/MessageViewInfoExtractor.java
+++ b/k9mail/src/main/java/com/fsck/k9/mailstore/MessageViewInfoExtractor.java
@@ -83,10 +83,9 @@ public class MessageViewInfoExtractor {
             return extractSimpleMessageForView(message, message);
         }
 
-        boolean isOpenPgpEncrypted =
-                MimeUtility.isSameMimeType(cryptoContentPart.getMimeType(), "multipart/encrypted") &&
-                        MimeUtility.isSameMimeType(getHeaderParameter(cryptoContentPart.getContentType(), "protocol"),
-                                "application/pgp-encrypted");
+        boolean isOpenPgpEncrypted = (MessageCryptoStructureDetector.isPartMultipartEncrypted(cryptoContentPart) &&
+                        MessageCryptoStructureDetector.isMultipartEncryptedOpenPgpProtocol(cryptoContentPart)) ||
+                        MessageCryptoStructureDetector.isPartPgpInlineEncrypted(cryptoContentPart);
         if (!K9.isOpenPgpProviderConfigured() && isOpenPgpEncrypted) {
             CryptoResultAnnotation noProviderAnnotation = CryptoResultAnnotation.createErrorAnnotation(
                     CryptoError.OPENPGP_ENCRYPTED_NO_PROVIDER, null);