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eliminate some BIGNUM allocation overhead

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orignal 2017-03-07 15:02:01 -05:00
parent 955b46534d
commit 044d6a2207
1 changed files with 12 additions and 15 deletions
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27
Signature.cpp
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@ -192,7 +192,8 @@ namespace crypto
BN_one (z3); // D = 1
}
BIGNUM * E = BN_new (), * F = BN_new (), * G = BN_new (), * H = BN_new ();
BN_CTX_start (ctx);
BIGNUM * E = BN_CTX_get (ctx), * F = BN_CTX_get (ctx), * G = BN_CTX_get (ctx), * H = BN_CTX_get (ctx);
BN_add (E, p1.x, p1.y);
BN_add (F, p2.x, p2.y);
BN_mul (E, E, F, ctx); // (x1 + y1)*(x2 + y2)
@ -207,7 +208,7 @@ namespace crypto
BN_mod_mul (z3, F, G, q, ctx); // z3 = F*G
BN_mod_mul (t3, E, H, q, ctx); // t3 = E*H
BN_free (E); BN_free (F); BN_free (G); BN_free (H);
BN_CTX_end (ctx);
return EDDSAPoint {x3, y3, z3, t3};
}
@ -231,7 +232,8 @@ namespace crypto
else
BN_one (z2); // z2 = 1
BIGNUM * E = BN_new (), * F = BN_new (), * G = BN_new (), * H = BN_new ();
BN_CTX_start (ctx);
BIGNUM * E = BN_CTX_get (ctx), * F = BN_CTX_get (ctx), * G = BN_CTX_get (ctx), * H = BN_CTX_get (ctx);
// E = (x+y)*(x+y)-A-B = x^2+y^2+2xy-A-B = 2xy
BN_mul (E, p.x, p.y, ctx);
BN_lshift1 (E, E); // E =2*x*y
@ -244,7 +246,7 @@ namespace crypto
BN_mod_mul (z2, F, G, q, ctx); // z2 = F*G
BN_mod_mul (t2, E, H, q, ctx); // t2 = E*H
BN_free (E); BN_free (F); BN_free (G); BN_free (H);
BN_CTX_end (ctx);
return EDDSAPoint {x2, y2, z2, t2};
}
@ -316,12 +318,11 @@ namespace crypto
bool IsOnCurve (const EDDSAPoint& p, BN_CTX * ctx) const
{
BIGNUM * x2 = BN_new ();
BN_CTX_start (ctx);
BIGNUM * x2 = BN_CTX_get (ctx), * y2 = BN_CTX_get (ctx), * tmp = BN_CTX_get (ctx);
BN_sqr (x2, p.x, ctx); // x^2
BIGNUM * y2 = BN_new ();
BN_sqr (y2, p.y, ctx); // y^2
// y^2 - x^2 - 1 - d*x^2*y^2
BIGNUM * tmp = BN_new ();
// y^2 - x^2 - 1 - d*x^2*y^2
BN_mul (tmp, d, x2, ctx);
BN_mul (tmp, tmp, y2, ctx);
BN_sub (tmp, y2, tmp);
@ -329,18 +330,16 @@ namespace crypto
BN_sub_word (tmp, 1);
BN_mod (tmp, tmp, q, ctx); // % q
bool ret = BN_is_zero (tmp);
BN_free (x2);
BN_free (y2);
BN_free (tmp);
BN_CTX_end (ctx);
return ret;
}
BIGNUM * RecoverX (const BIGNUM * y, BN_CTX * ctx) const
{
BIGNUM * y2 = BN_new ();
BN_CTX_start (ctx);
BIGNUM * y2 = BN_CTX_get (ctx), * xx = BN_CTX_get (ctx);
BN_sqr (y2, y, ctx); // y^2
// xx = (y^2 -1)*inv(d*y^2 +1)
BIGNUM * xx = BN_new ();
BN_mul (xx, d, y2, ctx);
BN_add_word (xx, 1);
BN_mod_inverse (xx, xx, q, ctx);
@ -356,8 +355,6 @@ namespace crypto
BN_mod_mul (x, x, I, q, ctx);
if (BN_is_odd (x))
BN_sub (x, q, x);
BN_free (y2);
BN_free (xx);
return x;
}