diff --git a/Crypto/PubKey/Ed448.hs b/Crypto/PubKey/Ed448.hs
new file mode 100644
index 0000000..0a5c069
--- /dev/null
+++ b/Crypto/PubKey/Ed448.hs
@@ -0,0 +1,102 @@
+-- |
+-- Module      : Crypto.PubKey.Ed448
+-- License     : BSD-style
+-- Maintainer  : John Galt <jgalt@centromere.net>
+-- Stability   : experimental
+-- Portability : unknown
+--
+-- Ed448 support
+--
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE MagicHash #-}
+module Crypto.PubKey.Ed448
+    ( SecretKey
+    , PublicKey
+    , DhSecret
+    -- * Smart constructors
+    , dhSecret
+    , publicKey
+    , secretKey
+    -- * methods
+    , dh
+    , toPublic
+    ) where
+
+import           Data.Word
+import           Foreign.Ptr
+import           GHC.Ptr
+
+import           Crypto.Error
+import           Crypto.Internal.Compat
+import           Crypto.Internal.Imports
+import           Crypto.Internal.ByteArray (ByteArrayAccess, ScrubbedBytes, Bytes, withByteArray)
+import qualified Crypto.Internal.ByteArray as B
+
+-- | A Ed448 Secret key
+newtype SecretKey = SecretKey ScrubbedBytes
+    deriving (Show,Eq,ByteArrayAccess,NFData)
+
+-- | A Ed448 public key
+newtype PublicKey = PublicKey Bytes
+    deriving (Show,Eq,ByteArrayAccess,NFData)
+
+-- | A Ed448 Diffie Hellman secret related to a
+-- public key and a secret key.
+newtype DhSecret = DhSecret ScrubbedBytes
+    deriving (Show,Eq,ByteArrayAccess,NFData)
+
+-- | Try to build a public key from a bytearray
+publicKey :: ByteArrayAccess bs => bs -> CryptoFailable PublicKey
+publicKey bs
+    | B.length bs == x448_bytes = CryptoPassed $ PublicKey $ B.copyAndFreeze bs (\_ -> return ())
+    | otherwise                 = CryptoFailed CryptoError_PublicKeySizeInvalid
+
+-- | Try to build a secret key from a bytearray
+secretKey :: ByteArrayAccess bs => bs -> CryptoFailable SecretKey
+secretKey bs
+    | B.length bs == x448_bytes = unsafeDoIO $
+        withByteArray bs $ \inp -> do
+            valid <- isValidPtr inp
+            if valid
+                then (CryptoPassed . SecretKey) <$> B.copy bs (\_ -> return ())
+                else return $ CryptoFailed CryptoError_SecretKeyStructureInvalid
+    | otherwise = CryptoFailed CryptoError_SecretKeySizeInvalid
+  where
+        isValidPtr :: Ptr Word8 -> IO Bool
+        isValidPtr _ =
+            return True
+{-# NOINLINE secretKey #-}
+
+-- | Create a DhSecret from a bytearray object
+dhSecret :: ByteArrayAccess b => b -> CryptoFailable DhSecret
+dhSecret bs
+    | B.length bs == x448_bytes = CryptoPassed $ DhSecret $ B.copyAndFreeze bs (\_ -> return ())
+    | otherwise                 = CryptoFailed CryptoError_SharedSecretSizeInvalid
+
+-- | Compute the Diffie Hellman secret from a public key and a secret key
+dh :: PublicKey -> SecretKey -> DhSecret
+dh (PublicKey pub) (SecretKey sec) = DhSecret <$>
+    B.allocAndFreeze x448_bytes $ \result ->
+    withByteArray sec           $ \psec   ->
+    withByteArray pub           $ \ppub   ->
+        ccryptonite_ed448 result psec ppub
+{-# NOINLINE dh #-}
+
+-- | Create a public key from a secret key
+toPublic :: SecretKey -> PublicKey
+toPublic (SecretKey sec) = PublicKey <$>
+    B.allocAndFreeze x448_bytes     $ \result ->
+    withByteArray sec               $ \psec   ->
+        ccryptonite_ed448 result psec basePoint
+  where
+        basePoint = Ptr "\x05\x00\x00\x00\x00\x00\x00\x00\x00x00\x00\x00\x00\x00\x00\x00\x00x00\x00\x00\x00\x00\x00\x00\x00x00\x00\x00\x00\x00\x00\x00\x00x00\x00\x00\x00\x00\x00\x00\x00x00\x00\x00\x00\x00\x00\x00\x00x00\x00\x00\x00\x00\x00\x00"#
+{-# NOINLINE toPublic #-}
+
+x448_bytes :: Int
+x448_bytes = 448 `quot` 8
+
+foreign import ccall "cryptonite_x448"
+    ccryptonite_ed448 :: Ptr Word8 -- ^ public
+                      -> Ptr Word8 -- ^ secret
+                      -> Ptr Word8 -- ^ basepoint
+                      -> IO ()
diff --git a/cbits/ed448/x448.c b/cbits/ed448/x448.c
new file mode 100644
index 0000000..5824fe9
--- /dev/null
+++ b/cbits/ed448/x448.c
@@ -0,0 +1,306 @@
+/* Copyright (c) 2015 Cryptography Research, Inc.
+ * Released under the MIT License.  See LICENSE.txt for license information.
+ */
+
+/**
+ * @file decaf.c
+ * @author Mike Hamburg
+ * @brief Decaf high-level functions.
+ */
+
+#include <stdint.h>
+#include "x448.h"
+
+#define WBITS 64 /* TODO */
+#define LBITS (WBITS * 7 / 8)
+#define X448_LIMBS (448/LBITS)
+
+#if WBITS == 64
+typedef uint64_t decaf_word_t;
+typedef int64_t decaf_sword_t;
+typedef __uint128_t decaf_dword_t;
+typedef __int128_t decaf_sdword_t;
+#elif WBITS == 32
+typedef uint32_t decaf_word_t;
+typedef int32_t decaf_sword_t;
+typedef uint64_t decaf_dword_t;
+typedef int64_t decaf_sdword_t;
+#else
+#error "WBITS must be 32 or 64"
+#endif
+
+typedef struct { decaf_word_t limb[X448_LIMBS]; } gf_s, gf[1];
+
+const unsigned char X448_BASE_POINT[X448_BYTES] = {5};
+
+static const gf ZERO = {{{0}}}, ONE = {{{1}}};
+
+#define LMASK ((((decaf_word_t)1)<<LBITS)-1)
+#if WBITS == 64
+static const gf P = {{{ LMASK, LMASK, LMASK, LMASK, LMASK-1, LMASK, LMASK, LMASK }}};
+#else
+static const gf P = {{{ LMASK,   LMASK, LMASK, LMASK, LMASK, LMASK, LMASK, LMASK,
+		      LMASK-1, LMASK, LMASK, LMASK, LMASK, LMASK, LMASK, LMASK }}};
+#endif
+static const int EDWARDS_D = -39081;
+
+#if (defined(__OPTIMIZE__) && !defined(__OPTIMIZE_SIZE__)) || defined(DECAF_FORCE_UNROLL)
+    #if X448_LIMBS==8
+    #define FOR_LIMB_U(i,op) { unsigned int i=0; \
+       op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; \
+    }
+    #elif X448_LIMBS==16
+    #define FOR_LIMB_U(i,op) { unsigned int i=0; \
+       op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; \
+       op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; op;i++; \
+    }
+    #else
+    #define FOR_LIMB_U(i,op) { unsigned int i=0; for (i=0; i<X448_LIMBS; i++)  { op; }}
+    #endif
+#else
+#define FOR_LIMB_U(i,op) { unsigned int i=0; for (i=0; i<X448_LIMBS; i++)  { op; }}
+#endif
+
+#define FOR_LIMB(i,op) { unsigned int i=0; for (i=0; i<X448_LIMBS; i++)  { op; }}
+
+/** Copy x = y */
+static void gf_cpy(gf x, const gf y) {
+    FOR_LIMB_U(i, x->limb[i] = y->limb[i]);
+}
+
+/** Mostly-unoptimized multiply (PERF), but at least it's unrolled. */
+static void
+gf_mul (gf c, const gf a, const gf b) {
+    gf aa;
+    gf_cpy(aa,a);
+
+    decaf_dword_t accum[X448_LIMBS] = {0};
+    FOR_LIMB_U(i, {
+        FOR_LIMB_U(j,{ accum[(i+j)%X448_LIMBS] += (decaf_dword_t)b->limb[i] * aa->limb[j]; });
+        aa->limb[(X448_LIMBS-1-i)^(X448_LIMBS/2)] += aa->limb[X448_LIMBS-1-i];
+    });
+
+    accum[X448_LIMBS-1] += accum[X448_LIMBS-2] >> LBITS;
+    accum[X448_LIMBS-2] &= LMASK;
+    accum[X448_LIMBS/2] += accum[X448_LIMBS-1] >> LBITS;
+    FOR_LIMB_U(j,{
+        accum[j] += accum[(j-1)%X448_LIMBS] >> LBITS;
+        accum[(j-1)%X448_LIMBS] &= LMASK;
+    });
+    FOR_LIMB_U(j, c->limb[j] = accum[j] );
+}
+
+/** No dedicated square (PERF) */
+#define gf_sqr(c,a) gf_mul(c,a,a)
+
+/** Inverse square root using addition chain. */
+static void
+gf_isqrt(gf y, const gf x) {
+    int i;
+#define STEP(s,m,n) gf_mul(s,m,c); gf_cpy(c,s); for (i=0;i<n;i++) gf_sqr(c,c);
+    gf a, b, c;
+    gf_sqr ( c,   x );
+    STEP(b,x,1);
+    STEP(b,x,3);
+    STEP(a,b,3);
+    STEP(a,b,9);
+    STEP(b,a,1);
+    STEP(a,x,18);
+    STEP(a,b,37);
+    STEP(b,a,37);
+    STEP(b,a,111);
+    STEP(a,b,1);
+    STEP(b,x,223);
+    gf_mul(y,a,c);
+}
+
+static void
+gf_inv(gf y, const gf x) {
+    gf z,w;
+    gf_sqr(z,x); /* x^2 */
+    gf_isqrt(w,z); /* +- 1/sqrt(x^2) = +- 1/x */
+    gf_sqr(z,w); /* 1/x^2 */
+    gf_mul(w,x,z); /* 1/x */
+    gf_cpy(y,w);
+}
+
+/** Weak reduce mod p. */
+static void
+gf_reduce(gf x) {
+    x->limb[X448_LIMBS/2] += x->limb[X448_LIMBS-1] >> LBITS;
+    FOR_LIMB_U(j,{
+        x->limb[j] += x->limb[(j-1)%X448_LIMBS] >> LBITS;
+        x->limb[(j-1)%X448_LIMBS] &= LMASK;
+    });
+}
+
+/** Add mod p.  Conservatively always weak-reduce. (PERF) */
+static void
+gf_add ( gf x, const gf y, const gf z ) {
+    FOR_LIMB_U(i, x->limb[i] = y->limb[i] + z->limb[i] );
+    gf_reduce(x);
+}
+
+/** Subtract mod p.  Conservatively always weak-reduce. (PERF) */
+static void
+gf_sub ( gf x, const gf y, const gf z ) {
+    FOR_LIMB_U(i, x->limb[i] = y->limb[i] - z->limb[i] + 2*P->limb[i] );
+    gf_reduce(x);
+}
+
+/** Constant time, if (swap) (x,y) = (y,x); */
+static void
+cond_swap(gf x, gf_s *__restrict__ y, decaf_word_t swap) {
+    FOR_LIMB_U(i, {
+        decaf_word_t s = (x->limb[i] ^ y->limb[i]) & swap;
+        x->limb[i] ^= s;
+        y->limb[i] ^= s;
+    });
+}
+
+/**
+ * Mul by signed int.  Not constant-time WRT the sign of that int.
+ * Just uses a full mul (PERF)
+ */
+static inline void
+gf_mlw(gf a, const gf b, int w) {
+    if (w>0) {
+        gf ww = {{{w}}};
+        gf_mul(a,b,ww);
+    } else {
+        gf ww = {{{-w}}};
+        gf_mul(a,b,ww);
+        gf_sub(a,ZERO,a);
+    }
+}
+
+/** Canonicalize */
+static void gf_canon ( gf a ) {
+    gf_reduce(a);
+
+    /* subtract p with borrow */
+    decaf_sdword_t carry = 0;
+    FOR_LIMB(i, {
+        carry = carry + a->limb[i] - P->limb[i];
+        a->limb[i] = carry & LMASK;
+        carry >>= LBITS;
+    });
+
+    decaf_word_t addback = carry;
+    carry = 0;
+
+    /* add it back */
+    FOR_LIMB(i, {
+        carry = carry + a->limb[i] + (P->limb[i] & addback);
+        a->limb[i] = carry & LMASK;
+        carry >>= LBITS;
+    });
+}
+
+/* Deserialize */
+static decaf_word_t
+gf_deser(gf s, const unsigned char ser[X448_BYTES]) {
+    unsigned int i, k=0, bits=0;
+    decaf_dword_t buf=0;
+    for (i=0; i<X448_BYTES; i++) {
+        buf |= (decaf_dword_t)ser[i]<<bits;
+        for (bits += 8; (bits>=LBITS || i==X448_BYTES-1) && k<X448_LIMBS; bits-=LBITS, buf>>=LBITS) {
+            s->limb[k++] = buf & LMASK;
+        }
+    }
+
+    decaf_sdword_t accum = 0;
+    FOR_LIMB(i, accum = (accum + s->limb[i] - P->limb[i]) >> WBITS );
+    return accum;
+}
+
+/* Serialize */
+static void
+gf_ser(uint8_t ser[X448_BYTES], gf a) {
+    gf_canon(a);
+    int k=0, bits=0;
+    decaf_dword_t buf=0;
+    FOR_LIMB(i, {
+        buf |= (decaf_dword_t)a->limb[i]<<bits;
+        for (bits += LBITS; (bits>=8 || i==X448_LIMBS-1) && k<X448_BYTES; bits-=8, buf>>=8) {
+            ser[k++]=buf;
+        }
+    });
+}
+
+int __attribute__((visibility("default"))) cryptonite_x448 (
+    unsigned char out[X448_BYTES],
+    const unsigned char scalar[X448_BYTES],
+    const unsigned char base[X448_BYTES]
+) {
+    gf x1, x2, z2, x3, z3, t1, t2;
+    gf_deser(x1,base);
+    gf_cpy(x2,ONE);
+    gf_cpy(z2,ZERO);
+    gf_cpy(x3,x1);
+    gf_cpy(z3,ONE);
+
+    int t;
+    decaf_word_t swap = 0;
+
+    for (t = 448-1; t>=0; t--) {
+        uint8_t sb = scalar[t/8];
+
+        /* Scalar conditioning */
+        if (t/8==0) sb &= 0xFC;
+        else if (t/8 == X448_BYTES-1) sb |= 0x80;
+
+        decaf_word_t k_t = (sb>>(t%8)) & 1;
+        k_t = -k_t; /* set to all 0s or all 1s */
+
+        swap ^= k_t;
+        cond_swap(x2,x3,swap);
+        cond_swap(z2,z3,swap);
+        swap = k_t;
+
+        gf_add(t1,x2,z2); /* A = x2 + z2 */
+        gf_sub(t2,x2,z2); /* B = x2 - z2 */
+        gf_sub(z2,x3,z3); /* D = x3 - z3 */
+        gf_mul(x2,t1,z2); /* DA */
+        gf_add(z2,z3,x3); /* C = x3 + z3 */
+        gf_mul(x3,t2,z2); /* CB */
+        gf_sub(z3,x2,x3); /* DA-CB */
+        gf_sqr(z2,z3);    /* (DA-CB)^2 */
+        gf_mul(z3,x1,z2); /* z3 = x1(DA-CB)^2 */
+        gf_add(z2,x2,x3); /* (DA+CB) */
+        gf_sqr(x3,z2);    /* x3 = (DA+CB)^2 */
+
+        gf_sqr(z2,t1);    /* AA = A^2 */
+        gf_sqr(t1,t2);    /* BB = B^2 */
+        gf_mul(x2,z2,t1); /* x2 = AA*BB */
+        gf_sub(t2,z2,t1); /* E = AA-BB */
+
+        gf_mlw(t1,t2,-EDWARDS_D); /* E*-d = a24*E */
+        gf_add(t1,t1,z2); /* AA + a24*E */
+        gf_mul(z2,t2,t1); /* z2 = E(AA+a24*E) */
+    }
+
+    /* Finish */
+    cond_swap(x2,x3,swap);
+    cond_swap(z2,z3,swap);
+    gf_inv(z2,z2);
+    gf_mul(x1,x2,z2);
+    gf_ser(out,x1);
+
+    decaf_sword_t nz = 0;
+    for (t=0; t<X448_BYTES; t++) {
+        nz |= out[t];
+    }
+    nz = (nz-1)>>8; /* 0 = succ, -1 = fail */
+
+    /* return value: 0 = succ, -1 = fail */
+    return nz;
+}
+
+int __attribute__((visibility("default")))
+cryptonite_x448_base (
+    unsigned char out[X448_BYTES],
+    const unsigned char scalar[X448_BYTES]
+) {
+    return cryptonite_x448(out,scalar,X448_BASE_POINT);
+}
diff --git a/cbits/ed448/x448.h b/cbits/ed448/x448.h
new file mode 100644
index 0000000..403e152
--- /dev/null
+++ b/cbits/ed448/x448.h
@@ -0,0 +1,25 @@
+
+#define X448_BYTES (448/8)
+
+/* The base point (5) */
+extern const unsigned char X448_BASE_POINT[X448_BYTES];
+
+/* Returns 0 on success, -1 on failure */
+int __attribute__((visibility("default")))
+cryptonite_x448 (
+    unsigned char out[X448_BYTES],
+    const unsigned char scalar[X448_BYTES],
+    const unsigned char base[X448_BYTES]
+);
+
+/* Returns 0 on success, -1 on failure
+ *
+ * Same as x448(out,scalar,X448_BASE_POINT), except that
+ * an implementation may optimize it.
+ */
+int __attribute__((visibility("default")))
+cryptonite_x448_base (
+    unsigned char out[X448_BYTES],
+    const unsigned char scalar[X448_BYTES]
+);
+
diff --git a/cryptonite.cabal b/cryptonite.cabal
index d9ffc3e..e0328b5 100644
--- a/cryptonite.cabal
+++ b/cryptonite.cabal
@@ -38,6 +38,7 @@ extra-doc-files:     README.md CHANGELOG.md
 extra-source-files:  cbits/*.h
                      cbits/aes/*.h
                      cbits/ed25519/*.h
+                     cbits/ed448/*.h
                      cbits/p256/*.h
                      cbits/blake2/ref/*.h
                      cbits/blake2/ref/*.c
@@ -121,6 +122,7 @@ Library
                      Crypto.PubKey.ECC.P256
                      Crypto.PubKey.ECC.Types
                      Crypto.PubKey.Ed25519
+                     Crypto.PubKey.Ed448
                      Crypto.PubKey.RSA
                      Crypto.PubKey.RSA.PKCS15
                      Crypto.PubKey.RSA.Prim
@@ -193,6 +195,7 @@ Library
                    , cbits/cryptonite_cpu.c
                    , cbits/curve25519/curve25519-donna.c
                    , cbits/ed25519/ed25519.c
+                   , cbits/ed448/x448.c
                    , cbits/p256/p256.c
                    , cbits/p256/p256_ec.c
                    , cbits/cryptonite_blake2s.c
diff --git a/tests/KAT_Ed448.hs b/tests/KAT_Ed448.hs
new file mode 100644
index 0000000..cc1c022
--- /dev/null
+++ b/tests/KAT_Ed448.hs
@@ -0,0 +1,23 @@
+{-# LANGUAGE OverloadedStrings #-}
+module KAT_Ed448 ( tests ) where
+
+import           Crypto.Error
+import qualified Crypto.PubKey.Ed448 as Ed448
+import           Data.ByteArray as B
+import           Imports
+
+alicePrivate = throwCryptoError $ Ed448.secretKey ("\x9a\x8f\x49\x25\xd1\x51\x9f\x57\x75\xcf\x46\xb0\x4b\x58\x00\xd4\xee\x9e\xe8\xba\xe8\xbc\x55\x65\xd4\x98\xc2\x8d\xd9\xc9\xba\xf5\x74\xa9\x41\x97\x44\x89\x73\x91\x00\x63\x82\xa6\xf1\x27\xab\x1d\x9a\xc2\xd8\xc0\xa5\x98\x72\x6b" :: ByteString)
+alicePublic  = throwCryptoError $ Ed448.publicKey ("\x9b\x08\xf7\xcc\x31\xb7\xe3\xe6\x7d\x22\xd5\xae\xa1\x21\x07\x4a\x27\x3b\xd2\xb8\x3d\xe0\x9c\x63\xfa\xa7\x3d\x2c\x22\xc5\xd9\xbb\xc8\x36\x64\x72\x41\xd9\x53\xd4\x0c\x5b\x12\xda\x88\x12\x0d\x53\x17\x7f\x80\xe5\x32\xc4\x1f\xa0" :: ByteString)
+bobPrivate   = throwCryptoError $ Ed448.secretKey ("\x1c\x30\x6a\x7a\xc2\xa0\xe2\xe0\x99\x0b\x29\x44\x70\xcb\xa3\x39\xe6\x45\x37\x72\xb0\x75\x81\x1d\x8f\xad\x0d\x1d\x69\x27\xc1\x20\xbb\x5e\xe8\x97\x2b\x0d\x3e\x21\x37\x4c\x9c\x92\x1b\x09\xd1\xb0\x36\x6f\x10\xb6\x51\x73\x99\x2d" :: ByteString)
+bobPublic    = throwCryptoError $ Ed448.publicKey ("\x3e\xb7\xa8\x29\xb0\xcd\x20\xf5\xbc\xfc\x0b\x59\x9b\x6f\xec\xcf\x6d\xa4\x62\x71\x07\xbd\xb0\xd4\xf3\x45\xb4\x30\x27\xd8\xb9\x72\xfc\x3e\x34\xfb\x42\x32\xa1\x3c\xa7\x06\xdc\xb5\x7a\xec\x3d\xae\x07\xbd\xc1\xc6\x7b\xf3\x36\x09" :: ByteString)
+aliceMultBob = "\x07\xff\xf4\x18\x1a\xc6\xcc\x95\xec\x1c\x16\xa9\x4a\x0f\x74\xd1\x2d\xa2\x32\xce\x40\xa7\x75\x52\x28\x1d\x28\x2b\xb6\x0c\x0b\x56\xfd\x24\x64\xc3\x35\x54\x39\x36\x52\x1c\x24\x40\x30\x85\xd5\x9a\x44\x9a\x50\x37\x51\x4a\x87\x9d" :: ByteString
+
+katTests :: [TestTree]
+katTests =
+    [ testCase "0" (aliceMultBob @=? B.convert (Ed448.dh alicePublic bobPrivate))
+    , testCase "1" (aliceMultBob @=? B.convert (Ed448.dh bobPublic alicePrivate))
+    ]
+
+tests = testGroup "Ed448"
+    [ testGroup "KATs" katTests
+    ]
diff --git a/tests/Tests.hs b/tests/Tests.hs
index d16c0e3..640eeb3 100644
--- a/tests/Tests.hs
+++ b/tests/Tests.hs
@@ -14,6 +14,7 @@ import qualified KAT_HMAC
 import qualified KAT_HKDF
 import qualified KAT_PBKDF2
 import qualified KAT_Curve25519
+import qualified KAT_Ed448
 import qualified KAT_Ed25519
 import qualified KAT_PubKey
 import qualified KAT_Scrypt
@@ -37,6 +38,7 @@ tests = testGroup "cryptonite"
         , KAT_HMAC.tests
         ]
     , KAT_Curve25519.tests
+    , KAT_Ed448.tests
     , KAT_Ed25519.tests
     , KAT_PubKey.tests
     , testGroup "KDF"