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rename some functions to improve consistency
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Submitted by: Sheueling Chang
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@45264
45264 committed Nov 23, 2002
1 parent 922fa76 commit 15994b0
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Showing 3 changed files with 19 additions and 20 deletions.
31 changes: 15 additions & 16 deletions crypto/ec/ec2_mult.c
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Original file line number Diff line number Diff line change
Expand Up @@ -79,7 +79,7 @@
* GF(2^m) without precomputation".
* modified to not require precomputation of c=b^{2^{m-1}}.
*/
static int Mdouble(const EC_GROUP *group, BIGNUM *x, BIGNUM *z, BN_CTX *ctx)
static int gf2m_Mdouble(const EC_GROUP *group, BIGNUM *x, BIGNUM *z, BN_CTX *ctx)
{
BIGNUM *t1;
int ret = 0;
Expand Down Expand Up @@ -110,7 +110,7 @@ static int Mdouble(const EC_GROUP *group, BIGNUM *x, BIGNUM *z, BN_CTX *ctx)
* Lopex, J. and Dahab, R. "Fast multiplication on elliptic curves over
* GF(2^m) without precomputation".
*/
static int Madd(const EC_GROUP *group, const BIGNUM *x, BIGNUM *x1, BIGNUM *z1,
static int gf2m_Madd(const EC_GROUP *group, const BIGNUM *x, BIGNUM *x1, BIGNUM *z1,
const BIGNUM *x2, const BIGNUM *z2, BN_CTX *ctx)
{
BIGNUM *t1, *t2;
Expand Down Expand Up @@ -138,17 +138,16 @@ static int Madd(const EC_GROUP *group, const BIGNUM *x, BIGNUM *x1, BIGNUM *z1,
return ret;
}

/* Compute the affine coordinates x2, y2=z2 for the point (x1/z1) and (x2/x2) in
* Montgomery projective coordinates.
* Uses algorithm Mxy in appendix of
/* Compute the x, y affine coordinates from the point (x1, z1) (x2, z2)
* using Montgomery point multiplication algorithm Mxy() in appendix of
* Lopex, J. and Dahab, R. "Fast multiplication on elliptic curves over
* GF(2^m) without precomputation".
* Returns:
* 0 on error
* 1 if return value should be the point at infinity
* 2 otherwise
*/
static int Mxy(const EC_GROUP *group, const BIGNUM *x, const BIGNUM *y, BIGNUM *x1,
static int gf2m_Mxy(const EC_GROUP *group, const BIGNUM *x, const BIGNUM *y, BIGNUM *x1,
BIGNUM *z1, BIGNUM *x2, BIGNUM *z2, BN_CTX *ctx)
{
BIGNUM *t3, *t4, *t5;
Expand Down Expand Up @@ -213,7 +212,7 @@ static int Mxy(const EC_GROUP *group, const BIGNUM *x, const BIGNUM *y, BIGNUM *
* Lopex, J. and Dahab, R. "Fast multiplication on elliptic curves over
* GF(2^m) without precomputation".
*/
static int point_multiply(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
const EC_POINT *point, BN_CTX *ctx)
{
BIGNUM *x1, *x2, *z1, *z2;
Expand Down Expand Up @@ -269,13 +268,13 @@ static int point_multiply(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scal
{
if (scalar->d[i] & mask)
{
if (!Madd(group, &point->X, x1, z1, x2, z2, ctx)) goto err;
if (!Mdouble(group, x2, z2, ctx)) goto err;
if (!gf2m_Madd(group, &point->X, x1, z1, x2, z2, ctx)) goto err;
if (!gf2m_Mdouble(group, x2, z2, ctx)) goto err;
}
else
{
if (!Madd(group, &point->X, x2, z2, x1, z1, ctx)) goto err;
if (!Mdouble(group, x1, z1, ctx)) goto err;
if (!gf2m_Madd(group, &point->X, x2, z2, x1, z1, ctx)) goto err;
if (!gf2m_Mdouble(group, x1, z1, ctx)) goto err;
}
mask >>= 1;
}
Expand All @@ -284,7 +283,7 @@ static int point_multiply(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scal
}

/* convert out of "projective" coordinates */
i = Mxy(group, &point->X, &point->Y, x1, z1, x2, z2, ctx);
i = gf2m_Mxy(group, &point->X, &point->Y, x1, z1, x2, z2, ctx);
if (i == 0) goto err;
else if (i == 1)
{
Expand Down Expand Up @@ -312,7 +311,7 @@ static int point_multiply(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scal
* scalar*group->generator + scalars[0]*points[0] + ... + scalars[num-1]*points[num-1]
* gracefully ignoring NULL scalar values.
*/
int ec_GF2m_mont_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
int ec_GF2m_simple_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
{
BN_CTX *new_ctx = NULL;
Expand Down Expand Up @@ -341,15 +340,15 @@ int ec_GF2m_mont_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,

if (scalar)
{
if (!point_multiply(group, p, scalar, group->generator, ctx)) goto err;
if (!ec_GF2m_montgomery_point_multiply(group, p, scalar, group->generator, ctx)) goto err;
if (BN_get_sign(scalar))
if (!group->meth->invert(group, p, ctx)) goto err;
if (!group->meth->add(group, r, r, p, ctx)) goto err;
}

for (i = 0; i < num; i++)
{
if (!point_multiply(group, p, scalars[i], points[i], ctx)) goto err;
if (!ec_GF2m_montgomery_point_multiply(group, p, scalars[i], points[i], ctx)) goto err;
if (BN_get_sign(scalars[i]))
if (!group->meth->invert(group, p, ctx)) goto err;
if (!group->meth->add(group, r, r, p, ctx)) goto err;
Expand All @@ -366,7 +365,7 @@ int ec_GF2m_mont_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,


/* Precomputation for point multiplication. */
int ec_GF2m_mont_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
int ec_GF2m_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
{
/* There is no precomputation to do for Montgomery scalar multiplication but
* since this implementation falls back to the wNAF multiplication for more than
Expand Down
4 changes: 2 additions & 2 deletions crypto/ec/ec2_smpl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -99,8 +99,8 @@ const EC_METHOD *EC_GF2m_simple_method(void)
ec_GF2m_simple_add,
ec_GF2m_simple_dbl,
ec_GF2m_simple_invert,
ec_GF2m_mont_mul,
ec_GF2m_mont_precompute_mult,
ec_GF2m_simple_mul,
ec_GF2m_precompute_mult,
ec_GF2m_simple_is_at_infinity,
ec_GF2m_simple_is_on_curve,
ec_GF2m_simple_cmp,
Expand Down
4 changes: 2 additions & 2 deletions crypto/ec/ec_lcl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -360,6 +360,6 @@ int ec_GF2m_simple_field_div(const EC_GROUP *, BIGNUM *r, const BIGNUM *a, const


/* method functions in ec2_mult.c */
int ec_GF2m_mont_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
int ec_GF2m_simple_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *);
int ec_GF2m_mont_precompute_mult(EC_GROUP *group, BN_CTX *ctx);
int ec_GF2m_precompute_mult(EC_GROUP *group, BN_CTX *ctx);

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