1 files changed, 58 insertions, 0 deletions

diff --git a/Codec/Encryption/OpenPGP/ASCIIArmor/Encode.hs b/Codec/Encryption/OpenPGP/ASCIIArmor/Encode.hs
new file mode 100644
index 0000000..d08c3c1
--- /dev/null
+++ b/Codec/Encryption/OpenPGP/ASCIIArmor/Encode.hs
@@ -0,0 +1,58 @@
+-- ASCIIArmor/Encode.hs: OpenPGP (RFC4880) ASCII armor implementation
+-- Copyright Ⓒ 2012  Clint Adams
+-- This software is released under the terms of the Expat (MIT) license.
+-- (See the LICENSE file).
+
+module Codec.Encryption.OpenPGP.ASCIIArmor.Encode (
+   armor
+) where
+
+import Codec.Encryption.OpenPGP.Serialize (putPackets)
+import Codec.Encryption.OpenPGP.Types
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Char8 as BC8
+import qualified Data.ByteString.Base64 as Base64
+import Data.Digest.CRC24 (crc24)
+import Data.Serialize.Put (runPut, putWord32be)
+import Data.String (IsString, fromString)
+
+armor :: (Integral a, Show a) => Armor a -> ByteString
+armor (Armor atype ahs ps) = beginLine atype `B.append` armorHeaders ahs `B.append` blankLine `B.append` armorData (opgpStream ps) `B.append` armorChecksum (opgpStream ps) `B.append` endLine atype
+
+blankLine :: ByteString
+blankLine = BC8.singleton '\n'
+
+beginLine :: (Integral a, Show a) => ArmorType a -> ByteString
+beginLine atype = BC8.pack "-----BEGIN PGP " `B.append` aType atype `B.append` BC8.pack "-----\n"
+
+endLine :: (Integral a, Show a) => ArmorType a -> ByteString
+endLine atype = BC8.pack "-----END PGP " `B.append` aType atype `B.append` BC8.pack "-----\n"
+
+aType :: (Integral a, Show a) => ArmorType a -> ByteString
+aType (ArmorMessage) = BC8.pack "MESSAGE"
+aType (ArmorPublicKeyBlock) = BC8.pack "PUBLIC KEY BLOCK"
+aType (ArmorPrivateKeyBlock) = BC8.pack "PRIVATE KEY BLOCK"
+aType (ArmorSplitMessage x y) = BC8.pack $ "MESSAGE, PART " ++ show x ++ "/" ++ show y
+aType (ArmorSplitMessageIndefinite x) = BC8.pack $ "MESSAGE, PART " ++ show x
+aType (ArmorSignature) = BC8.pack "SIGNATURE"
+
+armorHeaders :: [ArmorHeader] -> ByteString
+armorHeaders ahs = BC8.unlines . map armorHeader $ ahs
+    where
+        armorHeader :: ArmorHeader -> ByteString
+        armorHeader (k, v) = k `B.append` BC8.pack ": " `B.append` v
+
+opgpStream :: [Packet] -> ByteString
+opgpStream = runPut . putPackets
+
+armorData :: ByteString -> ByteString
+armorData = BC8.unlines . wrap76 . Base64.encode
+
+wrap76 :: ByteString -> [ByteString]
+wrap76 bs
+    | B.null bs = []
+    | otherwise = B.take 76 bs : wrap76 (B.drop 76 bs)
+
+armorChecksum :: ByteString -> ByteString
+armorChecksum = BC8.cons '=' . armorData . B.tail . runPut . putWord32be . crc24