1 files changed, 10 insertions, 0 deletions

diff --git a/Codec/Encryption/OpenPGP/ASCIIArmor/Encode.hs b/Codec/Encryption/OpenPGP/ASCIIArmor/Encode.hs
index 28bb3e6..00d9dd3 100644
--- a/Codec/Encryption/OpenPGP/ASCIIArmor/Encode.hs
+++ b/Codec/Encryption/OpenPGP/ASCIIArmor/Encode.hs
@@ -22,6 +22,7 @@ encode = B.concat . map armor
 
 armor :: Armor -> ByteString
 armor (Armor atype ahs bs) = beginLine atype `B.append` armorHeaders ahs `B.append` blankLine `B.append` armorData bs `B.append` armorChecksum bs `B.append` endLine atype
+armor (ClearSigned chs ctxt csig) = BC8.pack "-----BEGIN PGP SIGNED MESSAGE-----\n" `B.append` armorHeaders chs `B.append` blankLine `B.append` dashEscape ctxt `B.append` armor csig
 
 blankLine :: ByteString
 blankLine = BC8.singleton '\n'
@@ -57,3 +58,12 @@ wordWrap lw bs
 
 armorChecksum :: ByteString -> ByteString
 armorChecksum = BC8.cons '=' . armorData . B.tail . runPut . putWord32be . crc24
+
+dashEscape :: ByteString -> ByteString
+dashEscape = BC8.unlines . map escapeLine . BC8.lines
+    where
+        escapeLine :: ByteString -> ByteString
+        escapeLine l
+            | BC8.singleton '-' `B.isPrefixOf` l = BC8.pack "- " `B.append` l
+            | BC8.pack "From " `B.isPrefixOf` l = BC8.pack "- " `B.append` l
+            | otherwise = l