diff --git a/Tests/KATGCM.hs b/Tests/KATGCM.hs
--- a/Tests/KATGCM.hs
+++ b/Tests/KATGCM.hs
@@ -58,8 +58,36 @@
         , {-tag = -}"\x94\xd1\x47\xc3\xa2\xca\x93\xe9\x66\x93\x1e\x3b\xb3\xbb\x67\x01")
     ]
 
+vectors_aes256_enc :: [KATGCM]
+vectors_aes256_enc =
+    [
+        ( "\xb5\x2c\x50\x5a\x37\xd7\x8e\xda\x5d\xd3\x4f\x20\xc2\x25\x40\xea\x1b\x58\x96\x3c\xf8\xe5\xbf\x8f\xfa\x85\xf9\xf2\x49\x25\x05\xb4"
+        , "\x51\x6c\x33\x92\x9d\xf5\xa3\x28\x4f\xf4\x63\xd7"
+        , ""
+        , ""
+        , ""
+        , 16
+        , "\xbd\xc1\xac\x88\x4d\x33\x24\x57\xa1\xd2\x66\x4f\x16\x8c\x76\xf0")
+    ,   ( "\x78\xdc\x4e\x0a\xaf\x52\xd9\x35\xc3\xc0\x1e\xea\x57\x42\x8f\x00\xca\x1f\xd4\x75\xf5\xda\x86\xa4\x9c\x8d\xd7\x3d\x68\xc8\xe2\x23"
+        , "\xd7\x9c\xf2\x2d\x50\x4c\xc7\x93\xc3\xfb\x6c\x8a"
+        , "\xb9\x6b\xaa\x8c\x1c\x75\xa6\x71\xbf\xb2\xd0\x8d\x06\xbe\x5f\x36"
+        , ""
+        , ""
+        , 16
+        , "\x3e\x5d\x48\x6a\xa2\xe3\x0b\x22\xe0\x40\xb8\x57\x23\xa0\x6e\x76")
+    ,   ( "\xc3\xf1\x05\x86\xf2\x46\xaa\xca\xdc\xce\x37\x01\x44\x17\x70\xc0\x3c\xfe\xc9\x40\xaf\xe1\x90\x8c\x4c\x53\x7d\xf4\xe0\x1c\x50\xa0"
+        , "\x4f\x52\xfa\xa1\xfa\x67\xa0\xe5\xf4\x19\x64\x52"
+        , "\x46\xf9\xa2\x2b\x4e\x52\xe1\x52\x65\x13\xa9\x52\xdb\xee\x3b\x91\xf6\x95\x95\x50\x1e\x01\x77\xd5\x0f\xf3\x64\x63\x85\x88\xc0\x8d\x92\xfa\xb8\xc5\x8a\x96\x9b\xdc\xc8\x4c\x46\x8d\x84\x98\xc4\xf0\x63\x92\xb9\x9e\xd5\xe0\xc4\x84\x50\x7f\xc4\x8d\xc1\x8d\x87\xc4\x0e\x2e\xd8\x48\xb4\x31\x50\xbe\x9d\x36\xf1\x4c\xf2\xce\xf1\x31\x0b\xa4\xa7\x45\xad\xcc\x7b\xdc\x41\xf6"
+        , "\x79\xd9\x7e\xa3\xa2\xed\xd6\x50\x45\x82\x1e\xa7\x45\xa4\x47\x42"
+        , "\x56\x0c\xf7\x16\xe5\x61\x90\xe9\x39\x7c\x2f\x10\x36\x29\xeb\x1f"
+        , 16
+        , "\xff\x7c\x91\x24\x87\x96\x44\xe8\x05\x55\x68\x7d\x27\x3c\x55\xd8"
+        )
+    ]
+
 vectors_encrypt =
-	[ ("AES128 Enc", vectors_aes128_enc)
+    [ ("AES128 Enc", vectors_aes128_enc)
+    , ("AES256 Enc", vectors_aes256_enc)
     ]
 
 vectors_decrypt = []
diff --git a/Tests/Tests.hs b/Tests/Tests.hs
--- a/Tests/Tests.hs
+++ b/Tests/Tests.hs
@@ -69,6 +69,7 @@
     { kat_ECB  = map toKatECB KATECB.vectors_aes256_enc
     , kat_CBC  = map toKatCBC KATCBC.vectors_aes256_enc
     , kat_XTS  = map toKatXTS KATXTS.vectors_aes256_enc
+    , kat_AEAD = map toKatGCM KATGCM.vectors_aes256_enc
     }
 
 main = defaultMain
diff --git a/cbits/aes_generic.c b/cbits/aes_generic.c
--- a/cbits/aes_generic.c
+++ b/cbits/aes_generic.c
@@ -89,7 +89,7 @@
 };
 
 #define G(a,b,c,d,e,f) { a,b,c,d,e,f }
-uint8_t gmtab[256][6] =
+static uint8_t gmtab[256][6] =
 {
 	G(0x00, 0x00, 0x00, 0x00, 0x00, 0x00), G(0x02, 0x03, 0x09, 0x0b, 0x0d, 0x0e),
 	G(0x04, 0x06, 0x12, 0x16, 0x1a, 0x1c), G(0x06, 0x05, 0x1b, 0x1d, 0x17, 0x12),
diff --git a/cipher-aes.cabal b/cipher-aes.cabal
--- a/cipher-aes.cabal
+++ b/cipher-aes.cabal
@@ -1,5 +1,5 @@
 Name:                cipher-aes
-Version:             0.2.10
+Version:             0.2.11
 Description:
     Fast AES cipher implementation with advanced mode of operations.
     .