public static void ContextBuild(EcmultGenContext ctx, EventHandler <Callback> cb)
{
Ge[] r1 = new Ge[1024];
GeJ r2 = new GeJ();
GeJ geJ1 = new GeJ();
if (ctx.Prec != null)
{
return;
}
ctx.PrecInit();
Group.secp256k1_gej_set_ge(r2, Group.Secp256K1GeConstG);
byte[] bytes = Encoding.UTF8.GetBytes("The scalar for this x is unknown");
Fe fe = new Fe();
Ge ge = new Ge();
Field.SetB32(fe, bytes);
Group.secp256k1_ge_set_xo_var(ge, fe, false);
Group.secp256k1_gej_set_ge(geJ1, ge);
Group.secp256k1_gej_add_ge_var(geJ1, geJ1, Group.Secp256K1GeConstG, (Fe)null);
GeJ[] a = new GeJ[1024];
for (int index = 0; index < a.Length; ++index)
{
a[index] = new GeJ();
}
GeJ geJ2 = r2.Clone();
GeJ geJ3 = geJ1.Clone();
for (int index1 = 0; index1 < 64; ++index1)
{
a[index1 * 16] = geJ3.Clone();
for (int index2 = 1; index2 < 16; ++index2)
{
Group.secp256k1_gej_add_var(a[index1 * 16 + index2], a[index1 * 16 + index2 - 1], geJ2, (Fe)null);
}
for (int index2 = 0; index2 < 4; ++index2)
{
Group.secp256k1_gej_double_var(geJ2, geJ2, (Fe)null);
}
Group.secp256k1_gej_double_var(geJ3, geJ3, (Fe)null);
if (index1 == 62)
{
Group.secp256k1_gej_neg(geJ3, geJ3);
Group.secp256k1_gej_add_var(geJ3, geJ3, geJ1, (Fe)null);
}
}
for (int index = 0; index < r1.Length; ++index)
{
r1[index] = new Ge();
}
Group.secp256k1_ge_set_all_gej_var(r1, a, 1024, cb);
for (int index1 = 0; index1 < 64; ++index1)
{
for (int index2 = 0; index2 < 16; ++index2)
{
Group.ToStorage(ctx.Prec[index1][index2], r1[index1 * 16 + index2]);
}
}
EcMultGen.Blind(ctx, (byte[])null);
}
// // /** Double multiply: R = na*A + ng*G */
// // static void secp256k1_ecmult(const secp256k1_ecmult_context* ctx, secp256k1_gej* r, const secp256k1_gej* a, const secp256k1_scalar* na, const secp256k1_scalar* ng);
//#if defined(EXHAUSTIVE_TEST_ORDER)
///* We need to lower these values for exhaustive tests because
// * the tables cannot have infinities in them (this breaks the
// * affine-isomorphism stuff which tracks z-ratios) */
//#if EXHAUSTIVE_TEST_ORDER > 128
//#define WINDOW_A 5
//#define WINDOW_G 8
//#elif EXHAUSTIVE_TEST_ORDER > 8
//#define WINDOW_A 4
//#define WINDOW_G 4
//#else
//#define WINDOW_A 2
//#define WINDOW_G 2
//#endif
//#else
// /* optimal for 128-bit and 256-bit exponents. */
//#define WINDOW_A 5
// /** larger numbers may result in slightly better performance, at the cost of
// exponentially larger precomputed tables. */
//# ifdef USE_ENDOMORPHISM
// /** Two tables for window size 15: 1.375 MiB. */
//#define WINDOW_G 15
//#else
// /** One table for window size 16: 1.375 MiB. */
//#define WINDOW_G 16
//#endif
//#endif
/** The number of entries a table with precomputed multiples needs to have. */
//#define ECMULT_TABLE_SIZE(w) (1 << ((w)-2))
/// <summary>
/// Fill a table 'prej' with precomputed odd multiples of a. Prej will contain
/// the values [1*a,3*a,...,(2*n-1)*a], so it space for n values. zr[0] will
/// contain prej[0].z / a.z. The other zr[i] values = prej[i].z / prej[i-1].z.
/// Prej's Z values are undefined, except for the last value.
/// </summary>
/// <param name="n"></param>
/// <param name="prej"></param>
/// <param name="zr"></param>
/// <param name="a"></param>
static void secp256k1_ecmult_odd_multiples_table(int n, GeJ[] prej, Fe[] zr, GeJ a)
{
Debug.Assert(!a.Infinity);
GeJ d = new GeJ();
Group.secp256k1_gej_double_var(d, a, null);
/*
* Perform the additions on an isomorphism where 'd' is affine: drop the z coordinate
* of 'd', and scale the 1P starting value's x/y coordinates without changing its z.
*/
Ge dGe = new Ge();
dGe.X = d.X.Clone();
dGe.Y = d.Y.Clone();
dGe.Infinity = false;
Ge aGe = new Ge();
Group.secp256k1_ge_set_gej_zinv(aGe, a, d.Z);
prej[0].X = aGe.X.Clone();
prej[0].Y = aGe.Y.Clone();
prej[0].Z = a.Z.Clone();
prej[0].Infinity = false;
zr[0] = d.Z.Clone();
for (var i = 1; i < n; i++)
{
Group.secp256k1_gej_add_ge_var(prej[i], prej[i - 1], dGe, zr[i]);
}
/*
* Each point in 'prej' has a z coordinate too small by a factor of 'd.z'. Only
* the final point's z coordinate is actually used though, so just update that.
*/
Field.Mul(prej[n - 1].Z, prej[n - 1].Z, d.Z);
}
private static void secp256k1_ecmult_odd_multiples_table(int n, GeJ[] prej, Fe[] zr, GeJ a)
{
GeJ r1 = new GeJ();
Group.secp256k1_gej_double_var(r1, a, (Fe)null);
Ge b = new Ge();
b.X = r1.X.Clone();
b.Y = r1.Y.Clone();
b.Infinity = false;
Ge r2 = new Ge();
Group.secp256k1_ge_set_gej_zinv(r2, a, r1.Z);
prej[0].X = r2.X.Clone();
prej[0].Y = r2.Y.Clone();
prej[0].Z = a.Z.Clone();
prej[0].Infinity = false;
zr[0] = r1.Z.Clone();
for (int index = 1; index < n; ++index)
{
Group.secp256k1_gej_add_ge_var(prej[index], prej[index - 1], b, zr[index]);
}
Field.Mul(prej[n - 1].Z, prej[n - 1].Z, r1.Z);
}
public static void ContextBuild(EcmultGenContext ctx, EventHandler <Callback> cb)
{
#if !USE_ECMULT_STATIC_PRECOMPUTATION
Ge[] prec = new Ge[1024];
GeJ gj = new GeJ();
GeJ numsGej = new GeJ();
int i, j;
#endif
if (ctx.Prec != null)
{
return;
}
#if !USE_ECMULT_STATIC_PRECOMPUTATION
ctx.PrecInit();
/* get the generator */
Group.secp256k1_gej_set_ge(gj, Group.Secp256K1GeConstG);
/* Construct a group element with no known corresponding scalar (nothing up my sleeve). */
{
var numsB32 = Encoding.UTF8.GetBytes("The scalar for this x is unknown");
Fe numsX = new Fe();
Ge numsGe = new Ge();
var r = Field.SetB32(numsX, numsB32);
//(void)r;
Util.VERIFY_CHECK(r);
r = Group.secp256k1_ge_set_xo_var(numsGe, numsX, false);
//(void)r;
Util.VERIFY_CHECK(r);
Group.secp256k1_gej_set_ge(numsGej, numsGe);
/* Add G to make the bits in x uniformly distributed. */
Group.secp256k1_gej_add_ge_var(numsGej, numsGej, Group.Secp256K1GeConstG, null);
}
/* compute prec. */
{
GeJ[] precj = new GeJ[1024]; /* Jacobian versions of prec. */
for (int k = 0; k < precj.Length; k++)
{
precj[k] = new GeJ();
}
GeJ gbase;
GeJ numsbase;
gbase = gj.Clone(); /* 16^j * G */
numsbase = numsGej.Clone(); /* 2^j * nums. */
for (j = 0; j < 64; j++)
{
/* Set precj[j*16 .. j*16+15] to (numsbase, numsbase + gbase, ..., numsbase + 15*gbase). */
precj[j * 16] = numsbase.Clone();
for (i = 1; i < 16; i++)
{
Group.secp256k1_gej_add_var(precj[j * 16 + i], precj[j * 16 + i - 1], gbase, null);
}
/* Multiply gbase by 16. */
for (i = 0; i < 4; i++)
{
Group.secp256k1_gej_double_var(gbase, gbase, null);
}
/* Multiply numbase by 2. */
Group.secp256k1_gej_double_var(numsbase, numsbase, null);
if (j == 62)
{
/* In the last iteration, numsbase is (1 - 2^j) * nums instead. */
Group.secp256k1_gej_neg(numsbase, numsbase);
Group.secp256k1_gej_add_var(numsbase, numsbase, numsGej, null);
}
}
for (int k = 0; k < prec.Length; k++)
{
prec[k] = new Ge();
}
Group.secp256k1_ge_set_all_gej_var(prec, precj, 1024, cb);
}
for (j = 0; j < 64; j++)
{
for (i = 0; i < 16; i++)
{
Group.ToStorage(ctx.Prec[j][i], prec[j * 16 + i]);
}
}
#else
(void)cb;
ctx.prec = (secp256k1_ge_storage(*)[64][16])secp256k1_ecmult_static_context;
public static void secp256k1_gej_add_ge_var(GeJ r, GeJ a, Ge b, Fe rzr)
{
if (a.Infinity)
{
Group.secp256k1_gej_set_ge(r, b);
}
else if (b.Infinity)
{
if (rzr != null)
{
Field.SetInt(rzr, 1U);
}
r = a.Clone();
}
else
{
r.Infinity = false;
Fe fe1 = new Fe();
Field.Sqr(fe1, a.Z);
Fe fe2 = a.X.Clone();
Field.NormalizeWeak(fe2);
Fe fe3 = new Fe();
Field.Mul(fe3, b.X, fe1);
Fe fe4 = a.Y.Clone();
Field.NormalizeWeak(fe4);
Fe fe5 = new Fe();
Field.Mul(fe5, b.Y, fe1);
Field.Mul(fe5, fe5, a.Z);
Fe fe6 = new Fe();
Field.Negate(fe6, fe2, 1U);
Field.Add(fe6, fe3);
Fe fe7 = new Fe();
Field.Negate(fe7, fe4, 1U);
Field.Add(fe7, fe5);
if (Field.NormalizesToZeroVar(fe6))
{
if (Field.NormalizesToZeroVar(fe7))
{
Group.secp256k1_gej_double_var(r, a, rzr);
}
else
{
if (rzr != null)
{
Field.SetInt(rzr, 0U);
}
r.Infinity = true;
}
}
else
{
Fe fe8 = new Fe();
Field.Sqr(fe8, fe7);
Fe fe9 = new Fe();
Field.Sqr(fe9, fe6);
Fe fe10 = new Fe();
Field.Mul(fe10, fe6, fe9);
if (rzr != null)
{
rzr = fe6.Clone();
}
Field.Mul(r.Z, a.Z, fe6);
Fe fe11 = new Fe();
Field.Mul(fe11, fe2, fe9);
r.X = fe11.Clone();
Field.MulInt(r.X, 2U);
Field.Add(r.X, fe10);
Field.Negate(r.X, r.X, 3U);
Field.Add(r.X, fe8);
Field.Negate(r.Y, r.X, 5U);
Field.Add(r.Y, fe11);
Field.Mul(r.Y, r.Y, fe7);
Field.Mul(fe10, fe10, fe4);
Field.Negate(fe10, fe10, 1U);
Field.Add(r.Y, fe10);
}
}
}