Merge pull request #202 from ocheron/ed25519-arith-negate

Ed25519 arithmetic primitives
This commit is contained in:
Vincent Hanquez 2017-12-17 18:12:50 +00:00 committed by GitHub
commit 6346b8289c
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
14 changed files with 851 additions and 11 deletions

View File

@ -17,6 +17,7 @@ module Crypto.ECC
, Curve_P521R1(..)
, Curve_X25519(..)
, Curve_X448(..)
, Curve_Edwards25519(..)
, EllipticCurve(..)
, EllipticCurveDH(..)
, EllipticCurveArith(..)
@ -25,6 +26,7 @@ module Crypto.ECC
) where
import qualified Crypto.PubKey.ECC.P256 as P256
import qualified Crypto.ECC.Edwards25519 as Edwards25519
import qualified Crypto.ECC.Simple.Types as Simple
import qualified Crypto.ECC.Simple.Prim as Simple
import Crypto.Random
@ -101,6 +103,9 @@ class EllipticCurve curve => EllipticCurveArith curve where
-- | Add points on a curve
pointAdd :: proxy curve -> Point curve -> Point curve -> Point curve
-- | Negate a curve point
pointNegate :: proxy curve -> Point curve -> Point curve
-- | Scalar Multiplication on a curve
pointSmul :: proxy curve -> Scalar curve -> Point curve -> Point curve
@ -137,6 +142,7 @@ instance EllipticCurve Curve_P256R1 where
instance EllipticCurveArith Curve_P256R1 where
pointAdd _ a b = P256.pointAdd a b
pointNegate _ p = P256.pointNegate p
pointSmul _ s p = P256.pointMul s p
instance EllipticCurveDH Curve_P256R1 where
@ -158,6 +164,7 @@ instance EllipticCurve Curve_P384R1 where
instance EllipticCurveArith Curve_P384R1 where
pointAdd _ a b = Simple.pointAdd a b
pointNegate _ p = Simple.pointNegate p
pointSmul _ s p = Simple.pointMul s p
instance EllipticCurveDH Curve_P384R1 where
@ -180,6 +187,7 @@ instance EllipticCurve Curve_P521R1 where
instance EllipticCurveArith Curve_P521R1 where
pointAdd _ a b = Simple.pointAdd a b
pointNegate _ p = Simple.pointNegate p
pointSmul _ s p = Simple.pointMul s p
instance EllipticCurveDH Curve_P521R1 where
@ -225,6 +233,24 @@ instance EllipticCurveDH Curve_X448 where
where secret = X448.dh p s
ecdh prx s p = checkNonZeroDH (ecdhRaw prx s p)
data Curve_Edwards25519 = Curve_Edwards25519
deriving (Show,Data,Typeable)
instance EllipticCurve Curve_Edwards25519 where
type Point Curve_Edwards25519 = Edwards25519.Point
type Scalar Curve_Edwards25519 = Edwards25519.Scalar
curveSizeBits _ = 255
curveGenerateScalar _ = Edwards25519.scalarGenerate
curveGenerateKeyPair _ = toKeyPair <$> Edwards25519.scalarGenerate
where toKeyPair scalar = KeyPair (Edwards25519.toPoint scalar) scalar
encodePoint _ point = Edwards25519.pointEncode point
decodePoint _ bs = Edwards25519.pointDecode bs
instance EllipticCurveArith Curve_Edwards25519 where
pointAdd _ a b = Edwards25519.pointAdd a b
pointNegate _ p = Edwards25519.pointNegate p
pointSmul _ s p = Edwards25519.pointMul s p
checkNonZeroDH :: SharedSecret -> CryptoFailable SharedSecret
checkNonZeroDH s@(SharedSecret b)
| B.constAllZero b = CryptoFailed CryptoError_ScalarMultiplicationInvalid

373
Crypto/ECC/Edwards25519.hs Normal file
View File

@ -0,0 +1,373 @@
-- |
-- Module : Crypto.ECC.Edwards25519
-- License : BSD-style
-- Maintainer : Olivier Chéron <olivier.cheron@gmail.com>
-- Stability : experimental
-- Portability : unknown
--
-- Arithmetic primitives over curve edwards25519.
--
-- Twisted Edwards curves are a familly of elliptic curves allowing
-- complete addition formulas without any special case and no point at
-- infinity. Curve edwards25519 is based on prime 2^255 - 19 for
-- efficient implementation. Equation and parameters are given in
-- <https://tools.ietf.org/html/rfc7748 RFC 7748>.
--
-- This module provides types and primitive operations that are useful
-- to implement cryptographic schemes based on curve edwards25519:
--
-- - arithmetic functions for point addition, doubling, negation,
-- scalar multiplication with an arbitrary point, with the base point,
-- etc.
--
-- - arithmetic functions dealing with scalars modulo the prime order
-- L of the base point
--
-- All functions run in constant time unless noted otherwise.
--
-- Warnings:
--
-- 1. Curve edwards25519 has a cofactor h = 8 so the base point does
-- not generate the entire curve and points with order 2, 4, 8 exist.
-- When implementing cryptographic algorithms, special care must be
-- taken using one of the following methods:
--
-- - points must be checked for membership in the prime-order
-- subgroup
--
-- - or cofactor must be cleared by multiplying points by 8
--
-- Utility functions are provided to implement this. Testing
-- subgroup membership with 'pointHasPrimeOrder' is 50-time slower
-- than call 'pointMulByCofactor'.
--
-- 2. Scalar arithmetic is always reduced modulo L, allowing fixed
-- length and constant execution time, but this reduction is valid
-- only when points are in the prime-order subgroup.
--
-- 3. Because of modular reduction in this implementation it is not
-- possible to multiply points directly by scalars like 8.s or L.
-- This has to be decomposed into several steps.
--
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
module Crypto.ECC.Edwards25519
( Scalar
, Point
-- * Scalars
, scalarGenerate
, scalarDecodeLong
, scalarEncode
-- * Points
, pointDecode
, pointEncode
, pointHasPrimeOrder
-- * Arithmetic functions
, toPoint
, scalarAdd
, scalarMul
, pointNegate
, pointAdd
, pointDouble
, pointMul
, pointMulByCofactor
, pointsMulVarTime
) where
import Data.Bits
import Data.Word
import Foreign.C.Types
import Foreign.Ptr
import Foreign.Storable
import Crypto.Error
import Crypto.Internal.ByteArray (ByteArrayAccess, Bytes,
ScrubbedBytes, withByteArray)
import qualified Crypto.Internal.ByteArray as B
import Crypto.Internal.Compat
import Crypto.Internal.Imports
import Crypto.Random
scalarArraySize :: Int
scalarArraySize = 40 -- maximum [9 * 4 {- 32 bits -}, 5 * 8 {- 64 bits -}]
-- | A scalar modulo prime order of curve edwards25519.
newtype Scalar = Scalar ScrubbedBytes
deriving (Show,NFData)
instance Eq Scalar where
(Scalar s1) == (Scalar s2) = unsafeDoIO $
withByteArray s1 $ \ps1 ->
withByteArray s2 $ \ps2 ->
fmap (/= 0) (ed25519_scalar_eq ps1 ps2)
{-# NOINLINE (==) #-}
pointArraySize :: Int
pointArraySize = 160 -- maximum [4 * 10 * 4 {- 32 bits -}, 4 * 5 * 8 {- 64 bits -}]
-- | A point on curve edwards25519.
newtype Point = Point Bytes
deriving NFData
instance Show Point where
showsPrec d p =
let bs = pointEncode p :: Bytes
in showParen (d > 10) $ showString "Point "
. shows (B.convertToBase B.Base16 bs :: Bytes)
instance Eq Point where
(Point p1) == (Point p2) = unsafeDoIO $
withByteArray p1 $ \pp1 ->
withByteArray p2 $ \pp2 ->
fmap (/= 0) (ed25519_point_eq pp1 pp2)
{-# NOINLINE (==) #-}
-- | Generate a random scalar.
scalarGenerate :: MonadRandom randomly => randomly Scalar
scalarGenerate = throwCryptoError . scalarDecodeLong <$> generate
where
-- Scalar generation is based on a fixed number of bytes so that
-- there is no timing leak. But because of modular reduction
-- distribution is not uniform. We use many more bytes than
-- necessary so the probability bias is small. With 512 bits we
-- get 22% of scalars with a higher frequency, but the relative
-- probability difference is only 2^(-260).
generate :: MonadRandom randomly => randomly ScrubbedBytes
generate = getRandomBytes 64
-- | Serialize a scalar to binary, i.e. a 32-byte little-endian
-- number.
scalarEncode :: B.ByteArray bs => Scalar -> bs
scalarEncode (Scalar s) =
B.allocAndFreeze 32 $ \out ->
withByteArray s $ \ps -> ed25519_scalar_encode out ps
-- | Deserialize a little-endian number as a scalar. Input array can
-- have any length from 0 to 64 bytes.
--
-- Note: it is not advised to put secret information in the 3 lowest
-- bits of a scalar if this scalar may be multiplied to untrusted
-- points outside the prime-order subgroup.
scalarDecodeLong :: B.ByteArrayAccess bs => bs -> CryptoFailable Scalar
scalarDecodeLong bs
| B.length bs > 64 = CryptoFailed CryptoError_EcScalarOutOfBounds
| otherwise = unsafeDoIO $ withByteArray bs initialize
where
len = fromIntegral $ B.length bs
initialize inp = do
s <- B.alloc scalarArraySize $ \ps ->
ed25519_scalar_decode_long ps inp len
return $ CryptoPassed (Scalar s)
{-# NOINLINE scalarDecodeLong #-}
-- | Add two scalars.
scalarAdd :: Scalar -> Scalar -> Scalar
scalarAdd (Scalar a) (Scalar b) =
Scalar $ B.allocAndFreeze scalarArraySize $ \out ->
withByteArray a $ \pa ->
withByteArray b $ \pb ->
ed25519_scalar_add out pa pb
-- | Multiply two scalars.
scalarMul :: Scalar -> Scalar -> Scalar
scalarMul (Scalar a) (Scalar b) =
Scalar $ B.allocAndFreeze scalarArraySize $ \out ->
withByteArray a $ \pa ->
withByteArray b $ \pb ->
ed25519_scalar_mul out pa pb
-- | Multiplies a scalar with the curve base point.
toPoint :: Scalar -> Point
toPoint (Scalar scalar) =
Point $ B.allocAndFreeze pointArraySize $ \out ->
withByteArray scalar $ \pscalar ->
ed25519_point_base_scalarmul out pscalar
-- | Serialize a point to a 32-byte array.
--
-- Format is binary compatible with 'Crypto.PubKey.Ed25519.PublicKey'
-- from module "Crypto.PubKey.Ed25519".
pointEncode :: B.ByteArray bs => Point -> bs
pointEncode (Point p) =
B.allocAndFreeze 32 $ \out ->
withByteArray p $ \pp ->
ed25519_point_encode out pp
-- | Deserialize a 32-byte array as a point, ensuring the point is
-- valid on edwards25519.
--
-- /WARNING:/ variable time
pointDecode :: B.ByteArrayAccess bs => bs -> CryptoFailable Point
pointDecode bs
| B.length bs == 32 = unsafeDoIO $ withByteArray bs initialize
| otherwise = CryptoFailed CryptoError_PointSizeInvalid
where
initialize inp = do
(res, p) <- B.allocRet pointArraySize $ \pp ->
ed25519_point_decode_vartime pp inp
if res == 0 then return $ CryptoFailed CryptoError_PointCoordinatesInvalid
else return $ CryptoPassed (Point p)
{-# NOINLINE pointDecode #-}
-- | Test whether a point belongs to the prime-order subgroup
-- generated by the base point. Result is 'True' for the identity
-- point.
--
-- @
-- pointHasPrimeOrder p = 'pointNegate' p == 'pointMul' l_minus_one p
-- @
pointHasPrimeOrder :: Point -> Bool
pointHasPrimeOrder (Point p) = unsafeDoIO $
withByteArray p $ \pp ->
fmap (/= 0) (ed25519_point_has_prime_order pp)
{-# NOINLINE pointHasPrimeOrder #-}
-- | Negate a point.
pointNegate :: Point -> Point
pointNegate (Point a) =
Point $ B.allocAndFreeze pointArraySize $ \out ->
withByteArray a $ \pa ->
ed25519_point_negate out pa
-- | Add two points.
pointAdd :: Point -> Point -> Point
pointAdd (Point a) (Point b) =
Point $ B.allocAndFreeze pointArraySize $ \out ->
withByteArray a $ \pa ->
withByteArray b $ \pb ->
ed25519_point_add out pa pb
-- | Add a point to itself.
--
-- @
-- pointDouble p = 'pointAdd' p p
-- @
pointDouble :: Point -> Point
pointDouble (Point a) =
Point $ B.allocAndFreeze pointArraySize $ \out ->
withByteArray a $ \pa ->
ed25519_point_double out pa
-- | Multiply a point by h = 8.
--
-- @
-- pointMulByCofactor p = 'pointMul' scalar_8 p
-- @
pointMulByCofactor :: Point -> Point
pointMulByCofactor (Point a) =
Point $ B.allocAndFreeze pointArraySize $ \out ->
withByteArray a $ \pa ->
ed25519_point_mul_by_cofactor out pa
-- | Scalar multiplication over curve edwards25519.
--
-- Note: when the scalar had reduction modulo L and the input point
-- has a torsion component, the output point may not be in the
-- expected subgroup.
pointMul :: Scalar -> Point -> Point
pointMul (Scalar scalar) (Point base) =
Point $ B.allocAndFreeze pointArraySize $ \out ->
withByteArray scalar $ \pscalar ->
withByteArray base $ \pbase ->
ed25519_point_scalarmul out pbase pscalar
-- | Multiply the point @p@ with @s2@ and add a lifted to curve value @s1@.
--
-- @
-- pointsMulVarTime s1 s2 p = 'pointAdd' ('toPoint' s1) ('pointMul' s2 p)
-- @
--
-- /WARNING:/ variable time
pointsMulVarTime :: Scalar -> Scalar -> Point -> Point
pointsMulVarTime (Scalar s1) (Scalar s2) (Point p) =
Point $ B.allocAndFreeze pointArraySize $ \out ->
withByteArray s1 $ \ps1 ->
withByteArray s2 $ \ps2 ->
withByteArray p $ \pp ->
ed25519_base_double_scalarmul_vartime out ps1 pp ps2
foreign import ccall "cryptonite_ed25519_scalar_eq"
ed25519_scalar_eq :: Ptr Scalar
-> Ptr Scalar
-> IO CInt
foreign import ccall "cryptonite_ed25519_scalar_encode"
ed25519_scalar_encode :: Ptr Word8
-> Ptr Scalar
-> IO ()
foreign import ccall "cryptonite_ed25519_scalar_decode_long"
ed25519_scalar_decode_long :: Ptr Scalar
-> Ptr Word8
-> CSize
-> IO ()
foreign import ccall "cryptonite_ed25519_scalar_add"
ed25519_scalar_add :: Ptr Scalar -- sum
-> Ptr Scalar -- a
-> Ptr Scalar -- b
-> IO ()
foreign import ccall "cryptonite_ed25519_scalar_mul"
ed25519_scalar_mul :: Ptr Scalar -- out
-> Ptr Scalar -- a
-> Ptr Scalar -- b
-> IO ()
foreign import ccall "cryptonite_ed25519_point_encode"
ed25519_point_encode :: Ptr Word8
-> Ptr Point
-> IO ()
foreign import ccall "cryptonite_ed25519_point_decode_vartime"
ed25519_point_decode_vartime :: Ptr Point
-> Ptr Word8
-> IO CInt
foreign import ccall "cryptonite_ed25519_point_eq"
ed25519_point_eq :: Ptr Point
-> Ptr Point
-> IO CInt
foreign import ccall "cryptonite_ed25519_point_has_prime_order"
ed25519_point_has_prime_order :: Ptr Point
-> IO CInt
foreign import ccall "cryptonite_ed25519_point_negate"
ed25519_point_negate :: Ptr Point -- minus_a
-> Ptr Point -- a
-> IO ()
foreign import ccall "cryptonite_ed25519_point_add"
ed25519_point_add :: Ptr Point -- sum
-> Ptr Point -- a
-> Ptr Point -- b
-> IO ()
foreign import ccall "cryptonite_ed25519_point_double"
ed25519_point_double :: Ptr Point -- two_a
-> Ptr Point -- a
-> IO ()
foreign import ccall "cryptonite_ed25519_point_mul_by_cofactor"
ed25519_point_mul_by_cofactor :: Ptr Point -- eight_a
-> Ptr Point -- a
-> IO ()
foreign import ccall "cryptonite_ed25519_point_base_scalarmul"
ed25519_point_base_scalarmul :: Ptr Point -- scaled
-> Ptr Scalar -- scalar
-> IO ()
foreign import ccall "cryptonite_ed25519_point_scalarmul"
ed25519_point_scalarmul :: Ptr Point -- scaled
-> Ptr Point -- base
-> Ptr Scalar -- scalar
-> IO ()
foreign import ccall "cryptonite_ed25519_base_double_scalarmul_vartime"
ed25519_base_double_scalarmul_vartime :: Ptr Point -- combo
-> Ptr Scalar -- scalar1
-> Ptr Point -- base2
-> Ptr Scalar -- scalar2
-> IO ()

View File

@ -6,6 +6,7 @@ module Crypto.ECC.Simple.Prim
( scalarGenerate
, scalarFromInteger
, pointAdd
, pointNegate
, pointDouble
, pointBaseMul
, pointMul
@ -49,7 +50,7 @@ pointNegate :: Curve curve => Point curve -> Point curve
pointNegate PointO = PointO
pointNegate point@(Point x y) =
case curveType point of
CurvePrime {} -> Point x (-y)
CurvePrime (CurvePrimeParam p) -> Point x (p - y)
CurveBinary {} -> Point x (x `addF2m` y)
-- | Elliptic Curve point addition.

View File

@ -17,6 +17,7 @@ module Crypto.PubKey.ECC.P256
-- * Point arithmetic
, pointBase
, pointAdd
, pointNegate
, pointMul
, pointDh
, pointsMulVarTime
@ -106,6 +107,12 @@ pointAdd a b = withNewPoint $ \dx dy ->
withPoint a $ \ax ay -> withPoint b $ \bx by ->
ccryptonite_p256e_point_add ax ay bx by dx dy
-- | Negate a point
pointNegate :: Point -> Point
pointNegate a = withNewPoint $ \dx dy ->
withPoint a $ \ax ay -> do
ccryptonite_p256e_point_negate ax ay dx dy
-- | Multiply a point by a scalar
--
-- warning: variable time
@ -372,6 +379,11 @@ foreign import ccall "cryptonite_p256e_point_add"
-> Ptr P256X -> Ptr P256Y
-> IO ()
foreign import ccall "cryptonite_p256e_point_negate"
ccryptonite_p256e_point_negate :: Ptr P256X -> Ptr P256Y
-> Ptr P256X -> Ptr P256Y
-> IO ()
-- compute (out_x,out,y) = n1 * G + n2 * (in_x,in_y)
foreign import ccall "cryptonite_p256_points_mul_vartime"
ccryptonite_p256_points_mul_vartime :: Ptr P256Scalar -- n1

View File

@ -4,6 +4,7 @@
module Crypto.PubKey.ECC.Prim
( scalarGenerate
, pointAdd
, pointNegate
, pointDouble
, pointBaseMul
, pointMul
@ -30,9 +31,9 @@ scalarGenerate curve = generateBetween 1 (n - 1)
-- | Elliptic Curve point negation:
-- @pointNegate c p@ returns point @q@ such that @pointAdd c p q == PointO@.
pointNegate :: Curve -> Point -> Point
pointNegate _ PointO = PointO
pointNegate CurveFP{} (Point x y) = Point x (-y)
pointNegate CurveF2m{} (Point x y) = Point x (x `addF2m` y)
pointNegate _ PointO = PointO
pointNegate (CurveFP c) (Point x y) = Point x (ecc_p c - y)
pointNegate CurveF2m{} (Point x y) = Point x (x `addF2m` y)
-- | Elliptic Curve point addition.
--

View File

@ -0,0 +1,246 @@
/*
Public domain by Olivier Chéron <olivier.cheron@gmail.com>
Arithmetic extensions to Ed25519-donna
*/
/*
Scalar functions
*/
void
ED25519_FN(ed25519_scalar_encode) (unsigned char out[32], const bignum256modm in) {
contract256_modm(out, in);
}
void
ED25519_FN(ed25519_scalar_decode_long) (bignum256modm out, const unsigned char *in, size_t len) {
expand256_modm(out, in, len);
}
int
ED25519_FN(ed25519_scalar_eq) (const bignum256modm a, const bignum256modm b) {
bignum256modm_element_t e = 0;
for (int i = 0; i < bignum256modm_limb_size; i++) {
e |= a[i] ^ b[i];
}
return (int) (1 & ((e - 1) >> bignum256modm_bits_per_limb));
}
void
ED25519_FN(ed25519_scalar_add) (bignum256modm r, const bignum256modm x, const bignum256modm y) {
add256_modm(r, x, y);
}
void
ED25519_FN(ed25519_scalar_mul) (bignum256modm r, const bignum256modm x, const bignum256modm y) {
mul256_modm(r, x, y);
}
/*
Point functions
*/
void
ED25519_FN(ed25519_point_encode) (unsigned char r[32], const ge25519 *p) {
ge25519_pack(r, p);
}
int
ED25519_FN(ed25519_point_decode_vartime) (ge25519 *r, const unsigned char p[32]) {
unsigned char p_neg[32];
// invert parity bit of X coordinate so the point is negated twice
// (once here, once in ge25519_unpack_negative_vartime)
for (int i = 0; i < 31; i++) {
p_neg[i] = p[i];
}
p_neg[31] = p[31] ^ 0x80;
return ge25519_unpack_negative_vartime(r, p_neg);
}
int
ED25519_FN(ed25519_point_eq) (const ge25519 *p, const ge25519 *q) {
bignum25519 a, b;
unsigned char contract_a[32], contract_b[32];
int eq;
// pX * qZ = qX * pZ
curve25519_mul(a, p->x, q->z);
curve25519_contract(contract_a, a);
curve25519_mul(b, q->x, p->z);
curve25519_contract(contract_b, b);
eq = ed25519_verify(contract_a, contract_b, 32);
// pY * qZ = qY * pZ
curve25519_mul(a, p->y, q->z);
curve25519_contract(contract_a, a);
curve25519_mul(b, q->y, p->z);
curve25519_contract(contract_b, b);
eq &= ed25519_verify(contract_a, contract_b, 32);
return eq;
}
static int
ED25519_FN(ed25519_point_is_identity) (const ge25519 *p) {
static const unsigned char zero[32] = {0};
unsigned char check[32];
bignum25519 d;
int eq;
// pX = 0
curve25519_contract(check, p->x);
eq = ed25519_verify(check, zero, 32);
// pY - pZ = 0
curve25519_sub_reduce(d, p->y, p->z);
curve25519_contract(check, d);
eq &= ed25519_verify(check, zero, 32);
return eq;
}
void
ED25519_FN(ed25519_point_negate) (ge25519 *r, const ge25519 *p) {
curve25519_neg(r->x, p->x);
curve25519_copy(r->y, p->y);
curve25519_copy(r->z, p->z);
curve25519_neg(r->t, p->t);
}
void
ED25519_FN(ed25519_point_add) (ge25519 *r, const ge25519 *p, const ge25519 *q) {
ge25519_add(r, p, q);
}
void
ED25519_FN(ed25519_point_double) (ge25519 *r, const ge25519 *p) {
ge25519_double(r, p);
}
void
ED25519_FN(ed25519_point_mul_by_cofactor) (ge25519 *r, const ge25519 *p) {
ge25519_double_partial(r, p);
ge25519_double_partial(r, r);
ge25519_double(r, r);
}
void
ED25519_FN(ed25519_point_base_scalarmul) (ge25519 *r, const bignum256modm s) {
ge25519_scalarmult_base_niels(r, ge25519_niels_base_multiples, s);
}
#if defined(ED25519_64BIT)
typedef uint64_t ed25519_move_cond_word;
#else
typedef uint32_t ed25519_move_cond_word;
#endif
/* out = (flag) ? in : out */
DONNA_INLINE static void
ed25519_move_cond_pniels(ge25519_pniels *out, const ge25519_pniels *in, uint32_t flag) {
const int word_count = sizeof(ge25519_pniels) / sizeof(ed25519_move_cond_word);
const ed25519_move_cond_word nb = (ed25519_move_cond_word) flag - 1, b = ~nb;
ed25519_move_cond_word *outw = (ed25519_move_cond_word *) out;
const ed25519_move_cond_word *inw = (const ed25519_move_cond_word *) in;
// ge25519_pniels has 4 coordinates, so word_count is divisible by 4
for (int i = 0; i < word_count; i += 4) {
outw[i + 0] = (outw[i + 0] & nb) | (inw[i + 0] & b);
outw[i + 1] = (outw[i + 1] & nb) | (inw[i + 1] & b);
outw[i + 2] = (outw[i + 2] & nb) | (inw[i + 2] & b);
outw[i + 3] = (outw[i + 3] & nb) | (inw[i + 3] & b);
}
}
static void
ed25519_point_scalarmul_w_choose_pniels(ge25519_pniels *t, const ge25519_pniels table[15], uint32_t pos) {
// initialize t to identity, i.e. (1, 1, 1, 0)
memset(t, 0, sizeof(ge25519_pniels));
t->ysubx[0] = 1;
t->xaddy[0] = 1;
t->z[0] = 1;
// move one entry from table matching requested position,
// scanning all table to avoid cache-timing attack
//
// when pos == 0, no entry matches and this returns
// identity as expected
for (uint32_t i = 1; i < 16; i++) {
uint32_t flag = ((i ^ pos) - 1) >> 31;
ed25519_move_cond_pniels(t, table + i - 1, flag);
}
}
void
ED25519_FN(ed25519_point_scalarmul) (ge25519 *r, const ge25519 *p, const bignum256modm s) {
ge25519_pniels mult[15];
ge25519_pniels pn;
ge25519_p1p1 t;
unsigned char ss[32];
// transform scalar as little-endian number
contract256_modm(ss, s);
// initialize r to identity, i.e. ge25519 (0, 1, 1, 0)
memset(r, 0, sizeof(ge25519));
r->y[0] = 1;
r->z[0] = 1;
// precompute multiples of P: 1.P, 2.P, ..., 15.P
ge25519_full_to_pniels(&mult[0], p);
for (int i = 1; i < 15; i++) {
ge25519_pnielsadd(&mult[i], p, &mult[i-1]);
}
// 4-bit fixed window, still 256 doublings but 64 additions
for (int i = 31; i >= 0; i--) {
// higher bits in ss[i]
ed25519_point_scalarmul_w_choose_pniels(&pn, mult, ss[i] >> 4);
ge25519_pnielsadd_p1p1(&t, r, &pn, 0);
ge25519_p1p1_to_partial(r, &t);
ge25519_double_partial(r, r);
ge25519_double_partial(r, r);
ge25519_double_partial(r, r);
ge25519_double(r, r);
// lower bits in ss[i]
ed25519_point_scalarmul_w_choose_pniels(&pn, mult, ss[i] & 0x0F);
ge25519_pnielsadd_p1p1(&t, r, &pn, 0);
if (i > 0) {
ge25519_p1p1_to_partial(r, &t);
ge25519_double_partial(r, r);
ge25519_double_partial(r, r);
ge25519_double_partial(r, r);
ge25519_double(r, r);
} else {
ge25519_p1p1_to_full(r, &t);
}
}
}
void
ED25519_FN(ed25519_base_double_scalarmul_vartime) (ge25519 *r, const bignum256modm s1, const ge25519 *p2, const bignum256modm s2) {
// computes [s1]basepoint + [s2]p2
ge25519_double_scalarmult_vartime(r, p2, s2, s1);
}
int
ED25519_FN(ed25519_point_has_prime_order) (const ge25519 *p) {
static const bignum256modm sc_zero = {0};
ge25519 q;
// computes Q = m.P, vartime allowed because m is not secret
ED25519_FN(ed25519_base_double_scalarmul_vartime) (&q, sc_zero, p, modm_m);
return ED25519_FN(ed25519_point_is_identity) (&q);
}

View File

@ -287,7 +287,13 @@ ge25519_double_scalarmult_vartime(ge25519 *r, const ge25519 *p1, const bignum256
ge25519_nielsadd2_p1p1(&t, r, &ge25519_niels_sliding_multiples[abs(slide2[i]) / 2], (unsigned char)slide2[i] >> 7);
}
ge25519_p1p1_to_partial(r, &t);
// diverges from the original source code and resolves bug explained
// in <https://github.com/floodyberry/ed25519-donna/issues/31>
if (i == 0) {
ge25519_p1p1_to_full(r, &t);
} else {
ge25519_p1p1_to_partial(r, &t);
}
}
}

View File

@ -11,6 +11,7 @@
#include "ed25519.h"
#include "ed25519-randombytes.h"
#include "ed25519-hash.h"
#include "ed25519-cryptonite-exts.h"
/*
Generates a (extsk[0..31]) and aExt (extsk[32..63])

View File

@ -1303,3 +1303,14 @@ void cryptonite_p256e_point_add(
from_montgomery(out_x, px1);
from_montgomery(out_y, py1);
}
/* this function is not part of the original source
negate a point, i.e. (out_x, out_y) = (in_x, -in_y)
*/
void cryptonite_p256e_point_negate(
const cryptonite_p256_int *in_x, const cryptonite_p256_int *in_y,
cryptonite_p256_int *out_x, cryptonite_p256_int *out_y)
{
memcpy(out_x, in_x, P256_NBYTES);
cryptonite_p256_sub(&cryptonite_SECP256r1_p, in_y, out_y);
}

View File

@ -121,6 +121,7 @@ Library
Crypto.Data.AFIS
Crypto.Data.Padding
Crypto.ECC
Crypto.ECC.Edwards25519
Crypto.Error
Crypto.MAC.CMAC
Crypto.MAC.Poly1305
@ -241,7 +242,6 @@ Library
, cbits/cryptonite_xsalsa.c
, cbits/cryptonite_rc4.c
, cbits/cryptonite_cpu.c
, cbits/ed25519/ed25519.c
, cbits/p256/p256.c
, cbits/p256/p256_ec.c
, cbits/cryptonite_blake2s.c
@ -263,6 +263,7 @@ Library
, cbits/cryptonite_whirlpool.c
, cbits/cryptonite_scrypt.c
, cbits/cryptonite_pbkdf2.c
, cbits/ed25519/ed25519.c
include-dirs: cbits
, cbits/ed25519
, cbits/decaf/include
@ -370,6 +371,7 @@ Test-Suite test-cryptonite
ChaCha
BCrypt
ECC
ECC.Edwards25519
Hash
Imports
KAT_AES.KATCBC

147
tests/ECC/Edwards25519.hs Normal file
View File

@ -0,0 +1,147 @@
{-# LANGUAGE OverloadedStrings #-}
module ECC.Edwards25519 ( tests ) where
import Crypto.Error
import Crypto.ECC.Edwards25519
import qualified Data.ByteString as B
import Data.Word (Word8)
import Imports
instance Arbitrary Scalar where
arbitrary = fmap (throwCryptoError . scalarDecodeLong)
(arbitraryBS 64)
smallScalar :: Word8 -> Scalar
smallScalar = throwCryptoError . scalarDecodeLong . B.singleton
newtype PrimeOrder = PrimeOrder Point
deriving Show
-- points in the prime-order subgroup
instance Arbitrary PrimeOrder where
arbitrary = (PrimeOrder . toPoint) `fmap` arbitrary
-- arbitrary curve point, including points with a torsion component
instance Arbitrary Point where
arbitrary = do a <- arbitrary
b <- elements $ map smallScalar [0 .. 7]
return (pointsMulVarTime a b torsion8)
-- an 8-torsion point
torsion8 :: Point
torsion8 = throwCryptoError $ pointDecode ("\199\ETBjp=M\216O\186<\vv\r\DLEg\SI* S\250,9\204\198N\199\253w\146\172\ETXz" :: ByteString)
tests = testGroup "ECC.Edwards25519"
[ testGroup "vectors"
[ testCase "11*G" $ p011 @=? toPoint s011
, testCase "123*G" $ p123 @=? toPoint s123
, testCase "134*G" $ p134 @=? toPoint s134
, testCase "123*G + 11*G" $ p134 @=? pointAdd p123 p011
]
, testGroup "scalar arithmetic"
[ testProperty "scalarDecodeLong.scalarEncode==id" $ \s ->
let bs = scalarEncode s :: ByteString
ss = scalarDecodeLong bs
in CryptoPassed s `propertyEq` ss
, testCase "curve order" $ s0 @=? sN
, testProperty "addition with zero" $ \s ->
propertyHold [ eqTest "zero left" s (scalarAdd s0 s)
, eqTest "zero right" s (scalarAdd s s0)
]
, testProperty "addition associative" $ \sa sb sc ->
scalarAdd sa (scalarAdd sb sc) === scalarAdd (scalarAdd sa sb) sc
, testProperty "addition commutative" $ \sa sb ->
scalarAdd sa sb === scalarAdd sb sa
, testProperty "multiplication with zero" $ \s ->
propertyHold [ eqTest "zero left" s0 (scalarMul s0 s)
, eqTest "zero right" s0 (scalarMul s s0)
]
, testProperty "multiplication with one" $ \s ->
propertyHold [ eqTest "one left" s (scalarMul s1 s)
, eqTest "one right" s (scalarMul s s1)
]
, testProperty "multiplication associative" $ \sa sb sc ->
scalarMul sa (scalarMul sb sc) === scalarMul (scalarMul sa sb) sc
, testProperty "multiplication commutative" $ \sa sb ->
scalarMul sa sb === scalarMul sb sa
, testProperty "multiplication distributive" $ \sa sb sc ->
propertyHold [ eqTest "distributive left" ((sa `scalarMul` sb) `scalarAdd` (sa `scalarMul` sc))
(sa `scalarMul` (sb `scalarAdd` sc))
, eqTest "distributive right" ((sb `scalarMul` sa) `scalarAdd` (sc `scalarMul` sa))
((sb `scalarAdd` sc) `scalarMul` sa)
]
]
, testGroup "point arithmetic"
[ testProperty "pointDecode.pointEncode==id" $ \p ->
let bs = pointEncode p :: ByteString
p' = pointDecode bs
in CryptoPassed p `propertyEq` p'
, testProperty "pointEncode.pointDecode==id" $ \p ->
let b = pointEncode p :: ByteString
p' = pointDecode b
b' = pointEncode `fmap` p'
in CryptoPassed b `propertyEq` b'
, testProperty "addition with identity" $ \p ->
propertyHold [ eqTest "identity left" p (pointAdd p0 p)
, eqTest "identity right" p (pointAdd p p0)
]
, testProperty "addition associative" $ \pa pb pc ->
pointAdd pa (pointAdd pb pc) === pointAdd (pointAdd pa pb) pc
, testProperty "addition commutative" $ \pa pb ->
pointAdd pa pb === pointAdd pb pa
, testProperty "negation" $ \p ->
p0 `propertyEq` pointAdd p (pointNegate p)
, testProperty "doubling" $ \p ->
pointAdd p p `propertyEq` pointDouble p
, testProperty "multiplication by cofactor" $ \p ->
pointMul s8 p `propertyEq` pointMulByCofactor p
, testProperty "prime order" $ \(PrimeOrder p) ->
True `propertyEq` pointHasPrimeOrder p
, testCase "8-torsion point" $ do
assertBool "mul by 4" $ p0 /= pointMul s4 torsion8
assertBool "mul by 8" $ p0 == pointMul s8 torsion8
, testProperty "scalarmult with zero" $ \p ->
p0 `propertyEq` pointMul s0 p
, testProperty "scalarmult with one" $ \p ->
p `propertyEq` pointMul s1 p
, testProperty "scalarmult with two" $ \p ->
pointDouble p `propertyEq` pointMul s2 p
, testProperty "scalarmult with curve order - 1" $ \p ->
pointHasPrimeOrder p === (pointNegate p == pointMul sI p)
, testProperty "scalarmult commutative" $ \a b ->
pointMul a (toPoint b) === pointMul b (toPoint a)
, testProperty "scalarmult distributive" $ \x y (PrimeOrder p) ->
let pR = pointMul x p `pointAdd` pointMul y p
in pR `propertyEq` pointMul (x `scalarAdd` y) p
, testProperty "double scalarmult" $ \n1 n2 p ->
let pR = pointAdd (toPoint n1) (pointMul n2 p)
in pR `propertyEq` pointsMulVarTime n1 n2 p
]
]
where
p0 = toPoint s0
s0 = smallScalar 0
s1 = smallScalar 1
s2 = smallScalar 2
s4 = smallScalar 4
s8 = smallScalar 8
sI = throwCryptoError $ scalarDecodeLong ("\236\211\245\\\SUBc\DC2X\214\156\247\162\222\249\222\DC4\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\DLE" :: ByteString)
sN = throwCryptoError $ scalarDecodeLong ("\237\211\245\\\SUBc\DC2X\214\156\247\162\222\249\222\DC4\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\DLE" :: ByteString)
s011 = throwCryptoError $ scalarDecodeLong ("\011" :: ByteString)
s123 = throwCryptoError $ scalarDecodeLong ("\123" :: ByteString)
s134 = throwCryptoError $ scalarDecodeLong ("\134" :: ByteString)
p011 = throwCryptoError $ pointDecode ("\x13\x37\x03\x6a\xc3\x2d\x8f\x30\xd4\x58\x9c\x3c\x1c\x59\x58\x12\xce\x0f\xff\x40\xe3\x7c\x6f\x5a\x97\xab\x21\x3f\x31\x82\x90\xad" :: ByteString)
p123 = throwCryptoError $ pointDecode ("\xc4\xb8\x00\xc8\x70\x10\xf9\x46\x83\x03\xde\xea\x87\x65\x03\xe8\x86\xbf\xde\x19\x00\xe9\xe8\x46\xfd\x4c\x3c\xd0\x9c\x1c\xbc\x9f" :: ByteString)
p134 = throwCryptoError $ pointDecode ("\x51\x20\xab\xe0\x3c\xa2\xaf\x66\xc7\x7c\xa3\x20\xf0\xb2\x1f\xb5\x56\xf6\xb6\x5f\xdd\x7e\x32\x64\xc1\x4a\x30\xd9\x7b\xf7\xa7\x6f" :: ByteString)
-- Using <http://cr.yp.to/python/py>:
--
-- >>> import ed25519
-- >>> encodepoint(scalarmult(B, 11)).encode('hex')
-- '1337036ac32d8f30d4589c3c1c595812ce0fff40e37c6f5a97ab213f318290ad'
-- >>> encodepoint(scalarmult(B, 123)).encode('hex')
-- 'c4b800c87010f9468303deea876503e886bfde1900e9e846fd4c3cd09c1cbc9f'
-- >>> encodepoint(scalarmult(B, 134)).encode('hex')
-- '5120abe03ca2af66c77ca320f0b21fb556f6b65fdd7e3264c14a30d97bf7a76f'

View File

@ -147,7 +147,7 @@ arbitraryPoint aCurve =
eccTests = testGroup "ECC"
[ testGroup "valid-point" $ map doPointValidTest (zip [katZero..] vectorsPoint)
, testGroup "property"
, localOption (QuickCheckTests 20) $ testGroup "property"
[ testProperty "point-add" $ \aCurve (QAInteger r1) (QAInteger r2) ->
let curveN = ECC.ecc_n . ECC.common_curve $ aCurve
curveGen = ECC.ecc_g . ECC.common_curve $ aCurve
@ -155,14 +155,19 @@ eccTests = testGroup "ECC"
p2 = ECC.pointMul aCurve r2 curveGen
pR = ECC.pointMul aCurve ((r1 + r2) `mod` curveN) curveGen
in pR `propertyEq` ECC.pointAdd aCurve p1 p2
, localOption (QuickCheckTests 20) $
testProperty "point-mul-mul" $ \aCurve (QAInteger n1) (QAInteger n2) -> do
, testProperty "point-negate-add" $ \aCurve -> do
p <- arbitraryPoint aCurve
let o = ECC.pointAdd aCurve p (ECC.pointNegate aCurve p)
return $ ECC.PointO `propertyEq` o
, testProperty "point-negate-negate" $ \aCurve -> do
p <- arbitraryPoint aCurve
return $ p `propertyEq` ECC.pointNegate aCurve (ECC.pointNegate aCurve p)
, testProperty "point-mul-mul" $ \aCurve (QAInteger n1) (QAInteger n2) -> do
p <- arbitraryPoint aCurve
let pRes = ECC.pointMul aCurve (n1 * n2) p
let pDef = ECC.pointMul aCurve n1 (ECC.pointMul aCurve n2 p)
return $ pRes `propertyEq` pDef
, localOption (QuickCheckTests 20) $
testProperty "double-scalar-mult" $ \aCurve (QAInteger n1) (QAInteger n2) -> do
, testProperty "double-scalar-mult" $ \aCurve (QAInteger n1) (QAInteger n2) -> do
p1 <- arbitraryPoint aCurve
p2 <- arbitraryPoint aCurve
let pRes = ECC.pointAddTwoMuls aCurve n1 p1 n2 p2

View File

@ -113,6 +113,7 @@ tests = testGroup "P256"
in r @=? P256.pointAdd s t
, testProperty "lift-to-curve" $ propertyLiftToCurve
, testProperty "point-add" $ propertyPointAdd
, testProperty "point-negate" $ propertyPointNegate
]
]
where
@ -136,6 +137,12 @@ tests = testGroup "P256"
, eqTest "ecc" peR (pointP256ToECC pR)
]
propertyPointNegate r =
let p = P256.toPoint (unP256Scalar r)
pe = ECC.pointMul curve (unP256 r) curveGen
pR = P256.pointNegate p
in ECC.pointNegate curve pe `propertyEq` (pointP256ToECC pR)
i2ospScalar :: Integer -> Bytes
i2ospScalar i =
case i2ospOf 32 i of

View File

@ -7,6 +7,7 @@ import qualified Number
import qualified Number.F2m
import qualified BCrypt
import qualified ECC
import qualified ECC.Edwards25519
import qualified Hash
import qualified Poly1305
import qualified Salsa
@ -83,6 +84,7 @@ tests = testGroup "cryptonite"
]
, KAT_AFIS.tests
, ECC.tests
, ECC.Edwards25519.tests
]
main = defaultMain tests