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fd2cb59d26
ECC secp256k1: Removed the inline assembly code for AMD GPUs because the latest JIT compilers optimize it with the same efficiency
2237 lines
52 KiB
Common Lisp
2237 lines
52 KiB
Common Lisp
/**
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* Author......: See docs/credits.txt
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* License.....: MIT
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*
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* Furthermore, since elliptic curve operations are highly researched and optimized,
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* we've consulted a lot of online resources to implement this, including several papers and
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* example code.
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*
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* Credits where credits are due: there are a lot of nice projects that explain and/or optimize
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* elliptic curve operations (especially elliptic curve multiplications by a scalar).
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*
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* We want to shout out following projects, which were quite helpful when implementing this:
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* - secp256k1 by Pieter Wuille (https://github.com/bitcoin-core/secp256k1/, MIT)
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* - secp256k1-cl by hhanh00 (https://github.com/hhanh00/secp256k1-cl/, MIT)
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* - ec_pure_c by masterzorag (https://github.com/masterzorag/ec_pure_c/)
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* - ecc-gmp by leivaburto (https://github.com/leivaburto/ecc-gmp)
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* - micro-ecc by Ken MacKay (https://github.com/kmackay/micro-ecc/, BSD)
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* - curve_example by willem (https://gist.github.com/nlitsme/c9031c7b9bf6bb009e5a)
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* - py_ecc by Vitalik Buterin (https://github.com/ethereum/py_ecc/, MIT)
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*
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*
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* Some BigNum operations are implemented similar to micro-ecc which is licensed under these terms:
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* Copyright 2014 Ken MacKay, 2-Clause BSD License
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*
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* Redistribution and use in source and binary forms, with or without modification, are permitted
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* provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* ATTENTION: this code is NOT meant to be used in security critical environments that are at risk
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* of side-channel or timing attacks etc, it's only purpose is to make it work fast for GPGPU
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* (OpenCL/CUDA). Some attack vectors like side-channel and timing-attacks might be possible,
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* because of some optimizations used within this code (non-constant time etc).
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*/
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/*
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* Implementation considerations:
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* point double and point add are implemented similar to algorithms mentioned in this 2011 paper:
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* http://eprint.iacr.org/2011/338.pdf
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* (Fast and Regular Algorithms for Scalar Multiplication over Elliptic Curves by Matthieu Rivain)
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*
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* In theory we could use the Jacobian Co-Z enhancement to get rid of the larger buffer caused by
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* the z coordinates (and in this way reduce register pressure etc).
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* For the Co-Z improvement there are a lot of fast algorithms, but we might still be faster
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* with this implementation (b/c we allow non-constant time) without the Brier/Joye Montgomery-like
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* ladder. Of course, this claim would need to be verified and tested to see which one is faster
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* for our specific scenario at the end.
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*
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* We accomplish a "little" speedup by using scalars converted to w-NAF (non-adjacent form):
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* The general idea of w-NAF is to pre-compute some zi coefficients like below to reduce the
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* costly point additions by using a non-binary ("signed") number system (values other than just
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* 0 and 1, but ranging from -2^(w-1)-1 to 2^(w-1)-1). This works best with the left-to-right
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* binary algorithm such that we just add zi * P when adding point P (we pre-compute all the
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* possible zi * P values because the x/y coordinates are known before the kernel starts):
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*
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* // Example with window size w = 2 (i.e. mod 4 => & 3):
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* // 173 => 1 0 -1 0 -1 0 -1 0 1 = 2^8 - 2^6 - 2^4 - 2^2 + 1
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* int e = 0b10101101; // 173
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* int z[8 + 1] = { 0 }; // our zi/di, we need one extra slot to make the subtraction work
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*
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* int i = 0;
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*
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* while (e)
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* {
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* if (e & 1)
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* {
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* // for window size w = 3 it would be:
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* // => 2^(w-0) = 2^3 = 8
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* // => 2^(w-1) = 2^2 = 4
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*
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* int bit; // = 2 - (e & 3) for w = 2
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*
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* if ((e & 3) >= 2) // e % 4 == e & 3, use (e & 7) >= 4 for w = 3
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* bit = (e & 3) - 4; // (e & 7) - 8 for w = 3
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* else
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* bit = e & 3; // e & 7 for w = 3
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*
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* z[i] = bit;
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* e -= bit;
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* }
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*
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* e >>= 1; // e / 2
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* i++;
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* }
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*/
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#include "inc_ecc_secp256k1.h"
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DECLSPEC u32 sub (u32 *r, const u32 *a, const u32 *b)
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{
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u32 c = 0; // carry/borrow
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#if defined IS_NV && HAS_SUB == 1 && HAS_SUBC == 1
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asm volatile
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(
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"sub.cc.u32 %0, %9, %17;"
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"subc.cc.u32 %1, %10, %18;"
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"subc.cc.u32 %2, %11, %19;"
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"subc.cc.u32 %3, %12, %20;"
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"subc.cc.u32 %4, %13, %21;"
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"subc.cc.u32 %5, %14, %22;"
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"subc.cc.u32 %6, %15, %23;"
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"subc.cc.u32 %7, %16, %24;"
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"subc.u32 %8, 0, 0;"
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: "=r"(r[0]), "=r"(r[1]), "=r"(r[2]), "=r"(r[3]), "=r"(r[4]), "=r"(r[5]), "=r"(r[6]), "=r"(r[7]),
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"=r"(c)
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: "r"(a[0]), "r"(a[1]), "r"(a[2]), "r"(a[3]), "r"(a[4]), "r"(a[5]), "r"(a[6]), "r"(a[7]),
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"r"(b[0]), "r"(b[1]), "r"(b[2]), "r"(b[3]), "r"(b[4]), "r"(b[5]), "r"(b[6]), "r"(b[7])
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);
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// HIP doesnt support these so we stick to OpenCL (aka IS_AMD) - is also faster without asm
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//#elif (defined IS_AMD || defined IS_HIP) && HAS_VSUB == 1 && HAS_VSUBB == 1
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#elif 0
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__asm__ __volatile__
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(
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"V_SUB_U32 %0, %9, %17;"
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"V_SUBB_U32 %1, %10, %18;"
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"V_SUBB_U32 %2, %11, %19;"
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"V_SUBB_U32 %3, %12, %20;"
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"V_SUBB_U32 %4, %13, %21;"
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"V_SUBB_U32 %5, %14, %22;"
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"V_SUBB_U32 %6, %15, %23;"
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"V_SUBB_U32 %7, %16, %24;"
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"V_SUBB_U32 %8, 0, 0;"
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: "=v"(r[0]), "=v"(r[1]), "=v"(r[2]), "=v"(r[3]), "=v"(r[4]), "=v"(r[5]), "=v"(r[6]), "=v"(r[7]),
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"=v"(c)
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: "v"(a[0]), "v"(a[1]), "v"(a[2]), "v"(a[3]), "v"(a[4]), "v"(a[5]), "v"(a[6]), "v"(a[7]),
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"v"(b[0]), "v"(b[1]), "v"(b[2]), "v"(b[3]), "v"(b[4]), "v"(b[5]), "v"(b[6]), "v"(b[7])
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);
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#else
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for (u32 i = 0; i < 8; i++)
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{
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const u32 diff = a[i] - b[i] - c;
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if (diff != a[i]) c = (diff > a[i]);
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r[i] = diff;
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}
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#endif
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return c;
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}
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DECLSPEC u32 add (u32 *r, const u32 *a, const u32 *b)
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{
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u32 c = 0; // carry/borrow
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#if defined IS_NV && HAS_ADD == 1 && HAS_ADDC == 1
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asm volatile
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(
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"add.cc.u32 %0, %9, %17;"
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"addc.cc.u32 %1, %10, %18;"
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"addc.cc.u32 %2, %11, %19;"
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"addc.cc.u32 %3, %12, %20;"
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"addc.cc.u32 %4, %13, %21;"
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"addc.cc.u32 %5, %14, %22;"
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"addc.cc.u32 %6, %15, %23;"
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"addc.cc.u32 %7, %16, %24;"
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"addc.u32 %8, 0, 0;"
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: "=r"(r[0]), "=r"(r[1]), "=r"(r[2]), "=r"(r[3]), "=r"(r[4]), "=r"(r[5]), "=r"(r[6]), "=r"(r[7]),
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"=r"(c)
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: "r"(a[0]), "r"(a[1]), "r"(a[2]), "r"(a[3]), "r"(a[4]), "r"(a[5]), "r"(a[6]), "r"(a[7]),
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"r"(b[0]), "r"(b[1]), "r"(b[2]), "r"(b[3]), "r"(b[4]), "r"(b[5]), "r"(b[6]), "r"(b[7])
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);
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// HIP doesnt support these so we stick to OpenCL (aka IS_AMD) - is also faster without asm
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//#elif (defined IS_AMD || defined IS_HIP) && HAS_VSUB == 1 && HAS_VSUBB == 1
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#elif 0
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__asm__ __volatile__
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(
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"V_ADD_U32 %0, %9, %17;"
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"V_ADDC_U32 %1, %10, %18;"
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"V_ADDC_U32 %2, %11, %19;"
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"V_ADDC_U32 %3, %12, %20;"
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"V_ADDC_U32 %4, %13, %21;"
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"V_ADDC_U32 %5, %14, %22;"
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"V_ADDC_U32 %6, %15, %23;"
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"V_ADDC_U32 %7, %16, %24;"
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"V_ADDC_U32 %8, 0, 0;"
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: "=v"(r[0]), "=v"(r[1]), "=v"(r[2]), "=v"(r[3]), "=v"(r[4]), "=v"(r[5]), "=v"(r[6]), "=v"(r[7]),
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"=v"(c)
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: "v"(a[0]), "v"(a[1]), "v"(a[2]), "v"(a[3]), "v"(a[4]), "v"(a[5]), "v"(a[6]), "v"(a[7]),
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"v"(b[0]), "v"(b[1]), "v"(b[2]), "v"(b[3]), "v"(b[4]), "v"(b[5]), "v"(b[6]), "v"(b[7])
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);
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#else
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for (u32 i = 0; i < 8; i++)
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{
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const u32 t = a[i] + b[i] + c;
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if (t != a[i]) c = (t < a[i]);
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r[i] = t;
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}
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#endif
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return c;
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}
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DECLSPEC void sub_mod (u32 *r, const u32 *a, const u32 *b)
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{
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const u32 c = sub (r, a, b); // carry
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if (c)
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{
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u32 t[8];
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t[0] = SECP256K1_P0;
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t[1] = SECP256K1_P1;
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t[2] = SECP256K1_P2;
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t[3] = SECP256K1_P3;
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t[4] = SECP256K1_P4;
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t[5] = SECP256K1_P5;
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t[6] = SECP256K1_P6;
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t[7] = SECP256K1_P7;
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add (r, r, t);
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}
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}
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DECLSPEC void add_mod (u32 *r, const u32 *a, const u32 *b)
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{
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const u32 c = add (r, a, b); // carry
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/*
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* Modulo operation:
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*/
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// note: we could have an early exit in case of c == 1 => sub ()
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u32 t[8];
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t[0] = SECP256K1_P0;
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t[1] = SECP256K1_P1;
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t[2] = SECP256K1_P2;
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t[3] = SECP256K1_P3;
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t[4] = SECP256K1_P4;
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t[5] = SECP256K1_P5;
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t[6] = SECP256K1_P6;
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t[7] = SECP256K1_P7;
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// check if modulo operation is needed
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u32 mod = 1;
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if (c == 0)
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{
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for (int i = 7; i >= 0; i--)
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{
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if (r[i] < t[i])
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{
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mod = 0;
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break; // or return ! (check if faster)
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}
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if (r[i] > t[i]) break;
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}
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}
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if (mod == 1)
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{
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sub (r, r, t);
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}
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}
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DECLSPEC void mod_512 (u32 *n)
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{
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// we need to perform a modulo operation with 512-bit % 256-bit (bignum modulo):
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// the modulus is the secp256k1 group order
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// ATTENTION: for this function the byte-order is reversed (most significant bytes
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// at the left)
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/*
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the general modulo by shift and substract code (a = a % b):
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x = b;
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t = a >> 1;
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while (x <= t) x <<= 1;
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while (a >= b)
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{
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if (a >= x) a -= x;
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x >>= 1;
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}
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return a; // remainder
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*/
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u32 a[16];
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a[ 0] = n[ 0];
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a[ 1] = n[ 1];
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a[ 2] = n[ 2];
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a[ 3] = n[ 3];
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a[ 4] = n[ 4];
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a[ 5] = n[ 5];
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a[ 6] = n[ 6];
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a[ 7] = n[ 7];
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a[ 8] = n[ 8];
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a[ 9] = n[ 9];
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a[10] = n[10];
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a[11] = n[11];
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a[12] = n[12];
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a[13] = n[13];
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a[14] = n[14];
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a[15] = n[15];
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u32 b[16];
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b[ 0] = 0x00000000;
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b[ 1] = 0x00000000;
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b[ 2] = 0x00000000;
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b[ 3] = 0x00000000;
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b[ 4] = 0x00000000;
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b[ 5] = 0x00000000;
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b[ 6] = 0x00000000;
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b[ 7] = 0x00000000;
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b[ 8] = SECP256K1_N7;
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b[ 9] = SECP256K1_N6;
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b[10] = SECP256K1_N5;
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b[11] = SECP256K1_N4;
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b[12] = SECP256K1_N3;
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b[13] = SECP256K1_N2;
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b[14] = SECP256K1_N1;
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b[15] = SECP256K1_N0;
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/*
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* Start:
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*/
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// x = b (but with a fast "shift" trick to avoid the while loop)
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u32 x[16];
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x[ 0] = b[ 8]; // this is a trick: we just put the group order's most significant bit all the
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x[ 1] = b[ 9]; // way to the top to avoid doing the initial: while (x <= t) x <<= 1
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x[ 2] = b[10];
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x[ 3] = b[11];
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x[ 4] = b[12];
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x[ 5] = b[13];
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x[ 6] = b[14];
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x[ 7] = b[15];
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x[ 8] = 0x00000000;
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x[ 9] = 0x00000000;
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x[10] = 0x00000000;
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x[11] = 0x00000000;
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x[12] = 0x00000000;
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x[13] = 0x00000000;
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x[14] = 0x00000000;
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x[15] = 0x00000000;
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// a >= b
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while (a[0] >= b[0])
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{
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u32 l00 = a[ 0] < b[ 0];
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u32 l01 = a[ 1] < b[ 1];
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u32 l02 = a[ 2] < b[ 2];
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u32 l03 = a[ 3] < b[ 3];
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u32 l04 = a[ 4] < b[ 4];
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u32 l05 = a[ 5] < b[ 5];
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u32 l06 = a[ 6] < b[ 6];
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u32 l07 = a[ 7] < b[ 7];
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u32 l08 = a[ 8] < b[ 8];
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u32 l09 = a[ 9] < b[ 9];
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u32 l10 = a[10] < b[10];
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u32 l11 = a[11] < b[11];
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u32 l12 = a[12] < b[12];
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u32 l13 = a[13] < b[13];
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u32 l14 = a[14] < b[14];
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u32 l15 = a[15] < b[15];
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u32 e00 = a[ 0] == b[ 0];
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u32 e01 = a[ 1] == b[ 1];
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u32 e02 = a[ 2] == b[ 2];
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u32 e03 = a[ 3] == b[ 3];
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u32 e04 = a[ 4] == b[ 4];
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u32 e05 = a[ 5] == b[ 5];
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u32 e06 = a[ 6] == b[ 6];
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u32 e07 = a[ 7] == b[ 7];
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u32 e08 = a[ 8] == b[ 8];
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u32 e09 = a[ 9] == b[ 9];
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u32 e10 = a[10] == b[10];
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u32 e11 = a[11] == b[11];
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u32 e12 = a[12] == b[12];
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u32 e13 = a[13] == b[13];
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u32 e14 = a[14] == b[14];
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if (l00) break;
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if (l01 && e00) break;
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if (l02 && e00 && e01) break;
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if (l03 && e00 && e01 && e02) break;
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if (l04 && e00 && e01 && e02 && e03) break;
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if (l05 && e00 && e01 && e02 && e03 && e04) break;
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if (l06 && e00 && e01 && e02 && e03 && e04 && e05) break;
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if (l07 && e00 && e01 && e02 && e03 && e04 && e05 && e06) break;
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if (l08 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07) break;
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if (l09 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08) break;
|
|
if (l10 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09) break;
|
|
if (l11 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10) break;
|
|
if (l12 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10 && e11) break;
|
|
if (l13 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10 && e11 && e12) break;
|
|
if (l14 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10 && e11 && e12 && e13) break;
|
|
if (l15 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10 && e11 && e12 && e13 && e14) break;
|
|
|
|
// r = x (copy it to have the original values for the subtraction)
|
|
|
|
u32 r[16];
|
|
|
|
r[ 0] = x[ 0];
|
|
r[ 1] = x[ 1];
|
|
r[ 2] = x[ 2];
|
|
r[ 3] = x[ 3];
|
|
r[ 4] = x[ 4];
|
|
r[ 5] = x[ 5];
|
|
r[ 6] = x[ 6];
|
|
r[ 7] = x[ 7];
|
|
r[ 8] = x[ 8];
|
|
r[ 9] = x[ 9];
|
|
r[10] = x[10];
|
|
r[11] = x[11];
|
|
r[12] = x[12];
|
|
r[13] = x[13];
|
|
r[14] = x[14];
|
|
r[15] = x[15];
|
|
|
|
// x <<= 1
|
|
|
|
x[15] = x[15] >> 1 | x[14] << 31;
|
|
x[14] = x[14] >> 1 | x[13] << 31;
|
|
x[13] = x[13] >> 1 | x[12] << 31;
|
|
x[12] = x[12] >> 1 | x[11] << 31;
|
|
x[11] = x[11] >> 1 | x[10] << 31;
|
|
x[10] = x[10] >> 1 | x[ 9] << 31;
|
|
x[ 9] = x[ 9] >> 1 | x[ 8] << 31;
|
|
x[ 8] = x[ 8] >> 1 | x[ 7] << 31;
|
|
x[ 7] = x[ 7] >> 1 | x[ 6] << 31;
|
|
x[ 6] = x[ 6] >> 1 | x[ 5] << 31;
|
|
x[ 5] = x[ 5] >> 1 | x[ 4] << 31;
|
|
x[ 4] = x[ 4] >> 1 | x[ 3] << 31;
|
|
x[ 3] = x[ 3] >> 1 | x[ 2] << 31;
|
|
x[ 2] = x[ 2] >> 1 | x[ 1] << 31;
|
|
x[ 1] = x[ 1] >> 1 | x[ 0] << 31;
|
|
x[ 0] = x[ 0] >> 1;
|
|
|
|
// if (a >= r) a -= r;
|
|
|
|
l00 = a[ 0] < r[ 0];
|
|
l01 = a[ 1] < r[ 1];
|
|
l02 = a[ 2] < r[ 2];
|
|
l03 = a[ 3] < r[ 3];
|
|
l04 = a[ 4] < r[ 4];
|
|
l05 = a[ 5] < r[ 5];
|
|
l06 = a[ 6] < r[ 6];
|
|
l07 = a[ 7] < r[ 7];
|
|
l08 = a[ 8] < r[ 8];
|
|
l09 = a[ 9] < r[ 9];
|
|
l10 = a[10] < r[10];
|
|
l11 = a[11] < r[11];
|
|
l12 = a[12] < r[12];
|
|
l13 = a[13] < r[13];
|
|
l14 = a[14] < r[14];
|
|
l15 = a[15] < r[15];
|
|
|
|
e00 = a[ 0] == r[ 0];
|
|
e01 = a[ 1] == r[ 1];
|
|
e02 = a[ 2] == r[ 2];
|
|
e03 = a[ 3] == r[ 3];
|
|
e04 = a[ 4] == r[ 4];
|
|
e05 = a[ 5] == r[ 5];
|
|
e06 = a[ 6] == r[ 6];
|
|
e07 = a[ 7] == r[ 7];
|
|
e08 = a[ 8] == r[ 8];
|
|
e09 = a[ 9] == r[ 9];
|
|
e10 = a[10] == r[10];
|
|
e11 = a[11] == r[11];
|
|
e12 = a[12] == r[12];
|
|
e13 = a[13] == r[13];
|
|
e14 = a[14] == r[14];
|
|
|
|
if (l00) continue;
|
|
if (l01 && e00) continue;
|
|
if (l02 && e00 && e01) continue;
|
|
if (l03 && e00 && e01 && e02) continue;
|
|
if (l04 && e00 && e01 && e02 && e03) continue;
|
|
if (l05 && e00 && e01 && e02 && e03 && e04) continue;
|
|
if (l06 && e00 && e01 && e02 && e03 && e04 && e05) continue;
|
|
if (l07 && e00 && e01 && e02 && e03 && e04 && e05 && e06) continue;
|
|
if (l08 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07) continue;
|
|
if (l09 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08) continue;
|
|
if (l10 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09) continue;
|
|
if (l11 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10) continue;
|
|
if (l12 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10 && e11) continue;
|
|
if (l13 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10 && e11 && e12) continue;
|
|
if (l14 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10 && e11 && e12 && e13) continue;
|
|
if (l15 && e00 && e01 && e02 && e03 && e04 && e05 && e06 && e07 && e08 && e09 && e10 && e11 && e12 && e13 && e14) continue;
|
|
|
|
// substract (a -= r):
|
|
|
|
if ((r[ 0] | r[ 1] | r[ 2] | r[ 3] | r[ 4] | r[ 5] | r[ 6] | r[ 7] |
|
|
r[ 8] | r[ 9] | r[10] | r[11] | r[12] | r[13] | r[14] | r[15]) == 0) break;
|
|
|
|
r[ 0] = a[ 0] - r[ 0];
|
|
r[ 1] = a[ 1] - r[ 1];
|
|
r[ 2] = a[ 2] - r[ 2];
|
|
r[ 3] = a[ 3] - r[ 3];
|
|
r[ 4] = a[ 4] - r[ 4];
|
|
r[ 5] = a[ 5] - r[ 5];
|
|
r[ 6] = a[ 6] - r[ 6];
|
|
r[ 7] = a[ 7] - r[ 7];
|
|
r[ 8] = a[ 8] - r[ 8];
|
|
r[ 9] = a[ 9] - r[ 9];
|
|
r[10] = a[10] - r[10];
|
|
r[11] = a[11] - r[11];
|
|
r[12] = a[12] - r[12];
|
|
r[13] = a[13] - r[13];
|
|
r[14] = a[14] - r[14];
|
|
r[15] = a[15] - r[15];
|
|
|
|
// take care of the "borrow" (we can't do it the other way around 15...1 because r[x] is changed!)
|
|
|
|
if (r[ 1] > a[ 1]) r[ 0]--;
|
|
if (r[ 2] > a[ 2]) r[ 1]--;
|
|
if (r[ 3] > a[ 3]) r[ 2]--;
|
|
if (r[ 4] > a[ 4]) r[ 3]--;
|
|
if (r[ 5] > a[ 5]) r[ 4]--;
|
|
if (r[ 6] > a[ 6]) r[ 5]--;
|
|
if (r[ 7] > a[ 7]) r[ 6]--;
|
|
if (r[ 8] > a[ 8]) r[ 7]--;
|
|
if (r[ 9] > a[ 9]) r[ 8]--;
|
|
if (r[10] > a[10]) r[ 9]--;
|
|
if (r[11] > a[11]) r[10]--;
|
|
if (r[12] > a[12]) r[11]--;
|
|
if (r[13] > a[13]) r[12]--;
|
|
if (r[14] > a[14]) r[13]--;
|
|
if (r[15] > a[15]) r[14]--;
|
|
|
|
a[ 0] = r[ 0];
|
|
a[ 1] = r[ 1];
|
|
a[ 2] = r[ 2];
|
|
a[ 3] = r[ 3];
|
|
a[ 4] = r[ 4];
|
|
a[ 5] = r[ 5];
|
|
a[ 6] = r[ 6];
|
|
a[ 7] = r[ 7];
|
|
a[ 8] = r[ 8];
|
|
a[ 9] = r[ 9];
|
|
a[10] = r[10];
|
|
a[11] = r[11];
|
|
a[12] = r[12];
|
|
a[13] = r[13];
|
|
a[14] = r[14];
|
|
a[15] = r[15];
|
|
}
|
|
|
|
n[ 0] = a[ 0];
|
|
n[ 1] = a[ 1];
|
|
n[ 2] = a[ 2];
|
|
n[ 3] = a[ 3];
|
|
n[ 4] = a[ 4];
|
|
n[ 5] = a[ 5];
|
|
n[ 6] = a[ 6];
|
|
n[ 7] = a[ 7];
|
|
n[ 8] = a[ 8];
|
|
n[ 9] = a[ 9];
|
|
n[10] = a[10];
|
|
n[11] = a[11];
|
|
n[12] = a[12];
|
|
n[13] = a[13];
|
|
n[14] = a[14];
|
|
n[15] = a[15];
|
|
}
|
|
|
|
DECLSPEC void mul_mod (u32 *r, const u32 *a, const u32 *b) // TODO get rid of u64 ?
|
|
{
|
|
u32 t[16] = { 0 }; // we need up to double the space (2 * 8)
|
|
|
|
/*
|
|
* First start with the basic a * b multiplication:
|
|
*/
|
|
|
|
u32 t0 = 0;
|
|
u32 t1 = 0;
|
|
u32 c = 0;
|
|
|
|
for (u32 i = 0; i < 8; i++)
|
|
{
|
|
for (u32 j = 0; j <= i; j++)
|
|
{
|
|
u64 p = ((u64) a[j]) * b[i - j];
|
|
|
|
u64 d = ((u64) t1) << 32 | t0;
|
|
|
|
d += p;
|
|
|
|
t0 = (u32) d;
|
|
t1 = d >> 32;
|
|
|
|
c += d < p; // carry
|
|
}
|
|
|
|
t[i] = t0;
|
|
|
|
t0 = t1;
|
|
t1 = c;
|
|
|
|
c = 0;
|
|
}
|
|
|
|
for (u32 i = 8; i < 15; i++)
|
|
{
|
|
for (u32 j = i - 7; j < 8; j++)
|
|
{
|
|
u64 p = ((u64) a[j]) * b[i - j];
|
|
|
|
u64 d = ((u64) t1) << 32 | t0;
|
|
|
|
d += p;
|
|
|
|
t0 = (u32) d;
|
|
t1 = d >> 32;
|
|
|
|
c += d < p;
|
|
}
|
|
|
|
t[i] = t0;
|
|
|
|
t0 = t1;
|
|
t1 = c;
|
|
|
|
c = 0;
|
|
}
|
|
|
|
t[15] = t0;
|
|
|
|
|
|
|
|
/*
|
|
* Now do the modulo operation:
|
|
* (r = t % p)
|
|
*
|
|
* http://www.isys.uni-klu.ac.at/PDF/2001-0126-MT.pdf (p.354 or p.9 in that document)
|
|
*/
|
|
|
|
u32 tmp[16] = { 0 };
|
|
|
|
// c = 0;
|
|
|
|
// Note: SECP256K1_P = 2^256 - 2^32 - 977 (0x03d1 = 977)
|
|
// multiply t[8]...t[15] by omega:
|
|
|
|
for (u32 i = 0, j = 8; i < 8; i++, j++)
|
|
{
|
|
u64 p = ((u64) 0x03d1) * t[j] + c;
|
|
|
|
tmp[i] = (u32) p;
|
|
|
|
c = p >> 32;
|
|
}
|
|
|
|
tmp[8] = c;
|
|
|
|
c = add (tmp + 1, tmp + 1, t + 8); // modifies tmp[1]...tmp[8]
|
|
|
|
tmp[9] = c;
|
|
|
|
|
|
// r = t + tmp
|
|
|
|
c = add (r, t, tmp);
|
|
|
|
// multiply t[0]...t[7] by omega:
|
|
|
|
u32 c2 = 0;
|
|
|
|
// memset (t, 0, sizeof (t));
|
|
|
|
for (u32 i = 0, j = 8; i < 8; i++, j++)
|
|
{
|
|
u64 p = ((u64) 0x3d1) * tmp[j] + c2;
|
|
|
|
t[i] = (u32) p;
|
|
|
|
c2 = p >> 32;
|
|
}
|
|
|
|
t[8] = c2;
|
|
|
|
c2 = add (t + 1, t + 1, tmp + 8); // modifies t[1]...t[8]
|
|
|
|
t[9] = c2;
|
|
|
|
|
|
// r = r + t
|
|
|
|
c2 = add (r, r, t);
|
|
|
|
c += c2;
|
|
|
|
t[0] = SECP256K1_P0;
|
|
t[1] = SECP256K1_P1;
|
|
t[2] = SECP256K1_P2;
|
|
t[3] = SECP256K1_P3;
|
|
t[4] = SECP256K1_P4;
|
|
t[5] = SECP256K1_P5;
|
|
t[6] = SECP256K1_P6;
|
|
t[7] = SECP256K1_P7;
|
|
|
|
for (u32 i = c; i > 0; i--)
|
|
{
|
|
sub (r, r, t);
|
|
}
|
|
|
|
for (int i = 7; i >= 0; i--)
|
|
{
|
|
if (r[i] < t[i]) break;
|
|
|
|
if (r[i] > t[i])
|
|
{
|
|
sub (r, r, t);
|
|
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
DECLSPEC void sqrt_mod (u32 *r)
|
|
{
|
|
// Fermat's Little Theorem
|
|
// secp256k1: y^2 = x^3 + 7 % p
|
|
// y ^ (p - 1) = 1
|
|
// y ^ (p - 1) = (y^2) ^ ((p - 1) / 2) = 1 => y^2 = (y^2) ^ (((p - 1) / 2) + 1)
|
|
// => y = (y^2) ^ ((((p - 1) / 2) + 1) / 2)
|
|
// y = (y^2) ^ (((p - 1 + 2) / 2) / 2) = (y^2) ^ ((p + 1) / 4)
|
|
|
|
// y1 = (x^3 + 7) ^ ((p + 1) / 4)
|
|
// y2 = p - y1 (or y2 = y1 * -1 % p)
|
|
|
|
u32 s[8];
|
|
|
|
s[0] = SECP256K1_P0 + 1; // because of (p + 1) / 4 or use add (s, s, 1)
|
|
s[1] = SECP256K1_P1;
|
|
s[2] = SECP256K1_P2;
|
|
s[3] = SECP256K1_P3;
|
|
s[4] = SECP256K1_P4;
|
|
s[5] = SECP256K1_P5;
|
|
s[6] = SECP256K1_P6;
|
|
s[7] = SECP256K1_P7;
|
|
|
|
u32 t[8] = { 0 };
|
|
|
|
t[0] = 1;
|
|
|
|
for (u32 i = 255; i > 1; i--) // we just skip the last 2 multiplications (=> exp / 4)
|
|
{
|
|
mul_mod (t, t, t); // r * r
|
|
|
|
u32 idx = i >> 5;
|
|
u32 mask = 1 << (i & 0x1f);
|
|
|
|
if (s[idx] & mask)
|
|
{
|
|
mul_mod (t, t, r); // t * r
|
|
}
|
|
}
|
|
|
|
r[0] = t[0];
|
|
r[1] = t[1];
|
|
r[2] = t[2];
|
|
r[3] = t[3];
|
|
r[4] = t[4];
|
|
r[5] = t[5];
|
|
r[6] = t[6];
|
|
r[7] = t[7];
|
|
}
|
|
|
|
// (inverse (a, p) * a) % p == 1 (or think of a * a^-1 = a / a = 1)
|
|
|
|
DECLSPEC void inv_mod (u32 *a)
|
|
{
|
|
// How often does this really happen? it should "almost" never happen (but would be safer)
|
|
// if ((a[0] | a[1] | a[2] | a[3] | a[4] | a[5] | a[6] | a[7]) == 0) return;
|
|
|
|
u32 t0[8];
|
|
|
|
t0[0] = a[0];
|
|
t0[1] = a[1];
|
|
t0[2] = a[2];
|
|
t0[3] = a[3];
|
|
t0[4] = a[4];
|
|
t0[5] = a[5];
|
|
t0[6] = a[6];
|
|
t0[7] = a[7];
|
|
|
|
u32 p[8];
|
|
|
|
p[0] = SECP256K1_P0;
|
|
p[1] = SECP256K1_P1;
|
|
p[2] = SECP256K1_P2;
|
|
p[3] = SECP256K1_P3;
|
|
p[4] = SECP256K1_P4;
|
|
p[5] = SECP256K1_P5;
|
|
p[6] = SECP256K1_P6;
|
|
p[7] = SECP256K1_P7;
|
|
|
|
u32 t1[8];
|
|
|
|
t1[0] = SECP256K1_P0;
|
|
t1[1] = SECP256K1_P1;
|
|
t1[2] = SECP256K1_P2;
|
|
t1[3] = SECP256K1_P3;
|
|
t1[4] = SECP256K1_P4;
|
|
t1[5] = SECP256K1_P5;
|
|
t1[6] = SECP256K1_P6;
|
|
t1[7] = SECP256K1_P7;
|
|
|
|
u32 t2[8] = { 0 };
|
|
|
|
t2[0] = 0x00000001;
|
|
|
|
u32 t3[8] = { 0 };
|
|
|
|
u32 b = (t0[0] != t1[0])
|
|
| (t0[1] != t1[1])
|
|
| (t0[2] != t1[2])
|
|
| (t0[3] != t1[3])
|
|
| (t0[4] != t1[4])
|
|
| (t0[5] != t1[5])
|
|
| (t0[6] != t1[6])
|
|
| (t0[7] != t1[7]);
|
|
|
|
while (b)
|
|
{
|
|
if ((t0[0] & 1) == 0) // even
|
|
{
|
|
t0[0] = t0[0] >> 1 | t0[1] << 31;
|
|
t0[1] = t0[1] >> 1 | t0[2] << 31;
|
|
t0[2] = t0[2] >> 1 | t0[3] << 31;
|
|
t0[3] = t0[3] >> 1 | t0[4] << 31;
|
|
t0[4] = t0[4] >> 1 | t0[5] << 31;
|
|
t0[5] = t0[5] >> 1 | t0[6] << 31;
|
|
t0[6] = t0[6] >> 1 | t0[7] << 31;
|
|
t0[7] = t0[7] >> 1;
|
|
|
|
u32 c = 0;
|
|
|
|
if (t2[0] & 1) c = add (t2, t2, p);
|
|
|
|
t2[0] = t2[0] >> 1 | t2[1] << 31;
|
|
t2[1] = t2[1] >> 1 | t2[2] << 31;
|
|
t2[2] = t2[2] >> 1 | t2[3] << 31;
|
|
t2[3] = t2[3] >> 1 | t2[4] << 31;
|
|
t2[4] = t2[4] >> 1 | t2[5] << 31;
|
|
t2[5] = t2[5] >> 1 | t2[6] << 31;
|
|
t2[6] = t2[6] >> 1 | t2[7] << 31;
|
|
t2[7] = t2[7] >> 1 | c << 31;
|
|
}
|
|
else if ((t1[0] & 1) == 0)
|
|
{
|
|
t1[0] = t1[0] >> 1 | t1[1] << 31;
|
|
t1[1] = t1[1] >> 1 | t1[2] << 31;
|
|
t1[2] = t1[2] >> 1 | t1[3] << 31;
|
|
t1[3] = t1[3] >> 1 | t1[4] << 31;
|
|
t1[4] = t1[4] >> 1 | t1[5] << 31;
|
|
t1[5] = t1[5] >> 1 | t1[6] << 31;
|
|
t1[6] = t1[6] >> 1 | t1[7] << 31;
|
|
t1[7] = t1[7] >> 1;
|
|
|
|
u32 c = 0;
|
|
|
|
if (t3[0] & 1) c = add (t3, t3, p);
|
|
|
|
t3[0] = t3[0] >> 1 | t3[1] << 31;
|
|
t3[1] = t3[1] >> 1 | t3[2] << 31;
|
|
t3[2] = t3[2] >> 1 | t3[3] << 31;
|
|
t3[3] = t3[3] >> 1 | t3[4] << 31;
|
|
t3[4] = t3[4] >> 1 | t3[5] << 31;
|
|
t3[5] = t3[5] >> 1 | t3[6] << 31;
|
|
t3[6] = t3[6] >> 1 | t3[7] << 31;
|
|
t3[7] = t3[7] >> 1 | c << 31;
|
|
}
|
|
else
|
|
{
|
|
u32 gt = 0;
|
|
|
|
for (int i = 7; i >= 0; i--)
|
|
{
|
|
if (t0[i] > t1[i])
|
|
{
|
|
gt = 1;
|
|
|
|
break;
|
|
}
|
|
|
|
if (t0[i] < t1[i]) break;
|
|
}
|
|
|
|
if (gt)
|
|
{
|
|
sub (t0, t0, t1);
|
|
|
|
t0[0] = t0[0] >> 1 | t0[1] << 31;
|
|
t0[1] = t0[1] >> 1 | t0[2] << 31;
|
|
t0[2] = t0[2] >> 1 | t0[3] << 31;
|
|
t0[3] = t0[3] >> 1 | t0[4] << 31;
|
|
t0[4] = t0[4] >> 1 | t0[5] << 31;
|
|
t0[5] = t0[5] >> 1 | t0[6] << 31;
|
|
t0[6] = t0[6] >> 1 | t0[7] << 31;
|
|
t0[7] = t0[7] >> 1;
|
|
|
|
u32 lt = 0;
|
|
|
|
for (int i = 7; i >= 0; i--)
|
|
{
|
|
if (t2[i] < t3[i])
|
|
{
|
|
lt = 1;
|
|
|
|
break;
|
|
}
|
|
|
|
if (t2[i] > t3[i]) break;
|
|
}
|
|
|
|
if (lt) add (t2, t2, p);
|
|
|
|
sub (t2, t2, t3);
|
|
|
|
u32 c = 0;
|
|
|
|
if (t2[0] & 1) c = add (t2, t2, p);
|
|
|
|
t2[0] = t2[0] >> 1 | t2[1] << 31;
|
|
t2[1] = t2[1] >> 1 | t2[2] << 31;
|
|
t2[2] = t2[2] >> 1 | t2[3] << 31;
|
|
t2[3] = t2[3] >> 1 | t2[4] << 31;
|
|
t2[4] = t2[4] >> 1 | t2[5] << 31;
|
|
t2[5] = t2[5] >> 1 | t2[6] << 31;
|
|
t2[6] = t2[6] >> 1 | t2[7] << 31;
|
|
t2[7] = t2[7] >> 1 | c << 31;
|
|
}
|
|
else
|
|
{
|
|
sub (t1, t1, t0);
|
|
|
|
t1[0] = t1[0] >> 1 | t1[1] << 31;
|
|
t1[1] = t1[1] >> 1 | t1[2] << 31;
|
|
t1[2] = t1[2] >> 1 | t1[3] << 31;
|
|
t1[3] = t1[3] >> 1 | t1[4] << 31;
|
|
t1[4] = t1[4] >> 1 | t1[5] << 31;
|
|
t1[5] = t1[5] >> 1 | t1[6] << 31;
|
|
t1[6] = t1[6] >> 1 | t1[7] << 31;
|
|
t1[7] = t1[7] >> 1;
|
|
|
|
u32 lt = 0;
|
|
|
|
for (int i = 7; i >= 0; i--)
|
|
{
|
|
if (t3[i] < t2[i])
|
|
{
|
|
lt = 1;
|
|
|
|
break;
|
|
}
|
|
|
|
if (t3[i] > t2[i]) break;
|
|
}
|
|
|
|
if (lt) add (t3, t3, p);
|
|
|
|
sub (t3, t3, t2);
|
|
|
|
u32 c = 0;
|
|
|
|
if (t3[0] & 1) c = add (t3, t3, p);
|
|
|
|
t3[0] = t3[0] >> 1 | t3[1] << 31;
|
|
t3[1] = t3[1] >> 1 | t3[2] << 31;
|
|
t3[2] = t3[2] >> 1 | t3[3] << 31;
|
|
t3[3] = t3[3] >> 1 | t3[4] << 31;
|
|
t3[4] = t3[4] >> 1 | t3[5] << 31;
|
|
t3[5] = t3[5] >> 1 | t3[6] << 31;
|
|
t3[6] = t3[6] >> 1 | t3[7] << 31;
|
|
t3[7] = t3[7] >> 1 | c << 31;
|
|
}
|
|
}
|
|
|
|
// update b:
|
|
|
|
b = (t0[0] != t1[0])
|
|
| (t0[1] != t1[1])
|
|
| (t0[2] != t1[2])
|
|
| (t0[3] != t1[3])
|
|
| (t0[4] != t1[4])
|
|
| (t0[5] != t1[5])
|
|
| (t0[6] != t1[6])
|
|
| (t0[7] != t1[7]);
|
|
}
|
|
|
|
// set result:
|
|
|
|
a[0] = t2[0];
|
|
a[1] = t2[1];
|
|
a[2] = t2[2];
|
|
a[3] = t2[3];
|
|
a[4] = t2[4];
|
|
a[5] = t2[5];
|
|
a[6] = t2[6];
|
|
a[7] = t2[7];
|
|
}
|
|
|
|
/*
|
|
// everything from the formulas below of course MOD the prime:
|
|
|
|
// we use this formula:
|
|
|
|
X = (3/2 * x^2)^2 - 2 * x * y^2
|
|
Y = (3/2 * x^2) * (x * y^2 - X) - y^4
|
|
Z = y * z
|
|
|
|
this is identical to the more frequently used form:
|
|
|
|
X = (3 * x^2)^2 - 8 * x * y^2
|
|
Y = 3 * x^2 * (4 * x * y^2 - X) - 8 * y^4
|
|
Z = 2 * y * z
|
|
*/
|
|
|
|
DECLSPEC void point_double (u32 *x, u32 *y, u32 *z)
|
|
{
|
|
// How often does this really happen? it should "almost" never happen (but would be safer)
|
|
|
|
/*
|
|
if ((y[0] | y[1] | y[2] | y[3] | y[4] | y[5] | y[6] | y[7]) == 0)
|
|
{
|
|
x[0] = 0;
|
|
x[1] = 0;
|
|
x[2] = 0;
|
|
x[3] = 0;
|
|
x[4] = 0;
|
|
x[5] = 0;
|
|
x[6] = 0;
|
|
x[7] = 0;
|
|
|
|
y[0] = 0;
|
|
y[1] = 0;
|
|
y[2] = 0;
|
|
y[3] = 0;
|
|
y[4] = 0;
|
|
y[5] = 0;
|
|
y[6] = 0;
|
|
y[7] = 0;
|
|
|
|
z[0] = 0;
|
|
z[1] = 0;
|
|
z[2] = 0;
|
|
z[3] = 0;
|
|
z[4] = 0;
|
|
z[5] = 0;
|
|
z[6] = 0;
|
|
z[7] = 0;
|
|
|
|
return;
|
|
}
|
|
*/
|
|
|
|
u32 t1[8];
|
|
|
|
t1[0] = x[0];
|
|
t1[1] = x[1];
|
|
t1[2] = x[2];
|
|
t1[3] = x[3];
|
|
t1[4] = x[4];
|
|
t1[5] = x[5];
|
|
t1[6] = x[6];
|
|
t1[7] = x[7];
|
|
|
|
u32 t2[8];
|
|
|
|
t2[0] = y[0];
|
|
t2[1] = y[1];
|
|
t2[2] = y[2];
|
|
t2[3] = y[3];
|
|
t2[4] = y[4];
|
|
t2[5] = y[5];
|
|
t2[6] = y[6];
|
|
t2[7] = y[7];
|
|
|
|
u32 t3[8];
|
|
|
|
t3[0] = z[0];
|
|
t3[1] = z[1];
|
|
t3[2] = z[2];
|
|
t3[3] = z[3];
|
|
t3[4] = z[4];
|
|
t3[5] = z[5];
|
|
t3[6] = z[6];
|
|
t3[7] = z[7];
|
|
|
|
u32 t4[8];
|
|
u32 t5[8];
|
|
u32 t6[8];
|
|
|
|
mul_mod (t4, t1, t1); // t4 = x^2
|
|
|
|
mul_mod (t5, t2, t2); // t5 = y^2
|
|
|
|
mul_mod (t1, t1, t5); // t1 = x*y^2
|
|
|
|
mul_mod (t5, t5, t5); // t5 = t5^2 = y^4
|
|
|
|
// here the z^2 and z^4 is not needed for a = 0
|
|
|
|
mul_mod (t3, t2, t3); // t3 = x * z
|
|
|
|
add_mod (t2, t4, t4); // t2 = 2 * t4 = 2 * x^2
|
|
add_mod (t4, t4, t2); // t4 = 3 * t4 = 3 * x^2
|
|
|
|
// a * z^4 = 0 * 1^4 = 0
|
|
|
|
// don't discard the least significant bit it's important too!
|
|
|
|
u32 c = 0;
|
|
|
|
if (t4[0] & 1)
|
|
{
|
|
u32 t[8];
|
|
|
|
t[0] = SECP256K1_P0;
|
|
t[1] = SECP256K1_P1;
|
|
t[2] = SECP256K1_P2;
|
|
t[3] = SECP256K1_P3;
|
|
t[4] = SECP256K1_P4;
|
|
t[5] = SECP256K1_P5;
|
|
t[6] = SECP256K1_P6;
|
|
t[7] = SECP256K1_P7;
|
|
|
|
c = add (t4, t4, t); // t4 + SECP256K1_P
|
|
}
|
|
|
|
// right shift (t4 / 2):
|
|
|
|
t4[0] = t4[0] >> 1 | t4[1] << 31;
|
|
t4[1] = t4[1] >> 1 | t4[2] << 31;
|
|
t4[2] = t4[2] >> 1 | t4[3] << 31;
|
|
t4[3] = t4[3] >> 1 | t4[4] << 31;
|
|
t4[4] = t4[4] >> 1 | t4[5] << 31;
|
|
t4[5] = t4[5] >> 1 | t4[6] << 31;
|
|
t4[6] = t4[6] >> 1 | t4[7] << 31;
|
|
t4[7] = t4[7] >> 1 | c << 31;
|
|
|
|
mul_mod (t6, t4, t4); // t6 = t4^2 = (3/2 * x^2)^2
|
|
|
|
add_mod (t2, t1, t1); // t2 = 2 * t1
|
|
|
|
sub_mod (t6, t6, t2); // t6 = t6 - t2
|
|
sub_mod (t1, t1, t6); // t1 = t1 - t6
|
|
|
|
mul_mod (t4, t4, t1); // t4 = t4 * t1
|
|
|
|
sub_mod (t1, t4, t5); // t1 = t4 - t5
|
|
|
|
// => x = t6, y = t1, z = t3:
|
|
|
|
x[0] = t6[0];
|
|
x[1] = t6[1];
|
|
x[2] = t6[2];
|
|
x[3] = t6[3];
|
|
x[4] = t6[4];
|
|
x[5] = t6[5];
|
|
x[6] = t6[6];
|
|
x[7] = t6[7];
|
|
|
|
y[0] = t1[0];
|
|
y[1] = t1[1];
|
|
y[2] = t1[2];
|
|
y[3] = t1[3];
|
|
y[4] = t1[4];
|
|
y[5] = t1[5];
|
|
y[6] = t1[6];
|
|
y[7] = t1[7];
|
|
|
|
z[0] = t3[0];
|
|
z[1] = t3[1];
|
|
z[2] = t3[2];
|
|
z[3] = t3[3];
|
|
z[4] = t3[4];
|
|
z[5] = t3[5];
|
|
z[6] = t3[6];
|
|
z[7] = t3[7];
|
|
}
|
|
|
|
/*
|
|
* madd-2004-hmv:
|
|
* (from https://www.hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html)
|
|
* t1 = z1^2
|
|
* t2 = t1*z1
|
|
* t1 = t1*x2
|
|
* t2 = t2*y2
|
|
* t1 = t1-x1
|
|
* t2 = t2-y1
|
|
* z3 = z1*t1
|
|
* t3 = t1^2
|
|
* t4 = t3*t1
|
|
* t3 = t3*x1
|
|
* t1 = 2*t3
|
|
* x3 = t2^2
|
|
* x3 = x3-t1
|
|
* x3 = x3-t4
|
|
* t3 = t3-x3
|
|
* t3 = t3*t2
|
|
* t4 = t4*y1
|
|
* y3 = t3-t4
|
|
*/
|
|
|
|
DECLSPEC void point_add (u32 *x1, u32 *y1, u32 *z1, u32 *x2, u32 *y2) // z2 = 1
|
|
{
|
|
// How often does this really happen? it should "almost" never happen (but would be safer)
|
|
|
|
/*
|
|
if ((y2[0] | y2[1] | y2[2] | y2[3] | y2[4] | y2[5] | y2[6] | y2[7]) == 0) return;
|
|
|
|
if ((y1[0] | y1[1] | y1[2] | y1[3] | y1[4] | y1[5] | y1[6] | y1[7]) == 0)
|
|
{
|
|
x1[0] = x2[0];
|
|
x1[1] = x2[1];
|
|
x1[2] = x2[2];
|
|
x1[3] = x2[3];
|
|
x1[4] = x2[4];
|
|
x1[5] = x2[5];
|
|
x1[6] = x2[6];
|
|
x1[7] = x2[7];
|
|
|
|
y1[0] = y2[0];
|
|
y1[1] = y2[1];
|
|
y1[2] = y2[2];
|
|
y1[3] = y2[3];
|
|
y1[4] = y2[4];
|
|
y1[5] = y2[5];
|
|
y1[6] = y2[6];
|
|
y1[7] = y2[7];
|
|
|
|
z1[0] = z2[0];
|
|
z1[1] = z2[1];
|
|
z1[2] = z2[2];
|
|
z1[3] = z2[3];
|
|
z1[4] = z2[4];
|
|
z1[5] = z2[5];
|
|
z1[6] = z2[6];
|
|
z1[7] = z2[7];
|
|
|
|
return;
|
|
}
|
|
*/
|
|
|
|
// if x1 == x2 and y2 == y2 and z2 == z2 we need to double instead?
|
|
|
|
// x1/y1/z1:
|
|
|
|
u32 t1[8];
|
|
|
|
t1[0] = x1[0];
|
|
t1[1] = x1[1];
|
|
t1[2] = x1[2];
|
|
t1[3] = x1[3];
|
|
t1[4] = x1[4];
|
|
t1[5] = x1[5];
|
|
t1[6] = x1[6];
|
|
t1[7] = x1[7];
|
|
|
|
u32 t2[8];
|
|
|
|
t2[0] = y1[0];
|
|
t2[1] = y1[1];
|
|
t2[2] = y1[2];
|
|
t2[3] = y1[3];
|
|
t2[4] = y1[4];
|
|
t2[5] = y1[5];
|
|
t2[6] = y1[6];
|
|
t2[7] = y1[7];
|
|
|
|
u32 t3[8];
|
|
|
|
t3[0] = z1[0];
|
|
t3[1] = z1[1];
|
|
t3[2] = z1[2];
|
|
t3[3] = z1[3];
|
|
t3[4] = z1[4];
|
|
t3[5] = z1[5];
|
|
t3[6] = z1[6];
|
|
t3[7] = z1[7];
|
|
|
|
// x2/y2:
|
|
|
|
u32 t4[8];
|
|
|
|
t4[0] = x2[0];
|
|
t4[1] = x2[1];
|
|
t4[2] = x2[2];
|
|
t4[3] = x2[3];
|
|
t4[4] = x2[4];
|
|
t4[5] = x2[5];
|
|
t4[6] = x2[6];
|
|
t4[7] = x2[7];
|
|
|
|
u32 t5[8];
|
|
|
|
t5[0] = y2[0];
|
|
t5[1] = y2[1];
|
|
t5[2] = y2[2];
|
|
t5[3] = y2[3];
|
|
t5[4] = y2[4];
|
|
t5[5] = y2[5];
|
|
t5[6] = y2[6];
|
|
t5[7] = y2[7];
|
|
|
|
u32 t6[8];
|
|
u32 t7[8];
|
|
u32 t8[8];
|
|
u32 t9[8];
|
|
|
|
mul_mod (t6, t3, t3); // t6 = t3^2
|
|
|
|
mul_mod (t7, t6, t3); // t7 = t6*t3
|
|
mul_mod (t6, t6, t4); // t6 = t6*t4
|
|
mul_mod (t7, t7, t5); // t7 = t7*t5
|
|
|
|
sub_mod (t6, t6, t1); // t6 = t6-t1
|
|
sub_mod (t7, t7, t2); // t7 = t7-t2
|
|
|
|
mul_mod (t8, t3, t6); // t8 = t3*t6
|
|
mul_mod (t4, t6, t6); // t4 = t6^2
|
|
mul_mod (t9, t4, t6); // t9 = t4*t6
|
|
mul_mod (t4, t4, t1); // t4 = t4*t1
|
|
|
|
// left shift (t4 * 2):
|
|
|
|
t6[7] = t4[7] << 1 | t4[6] >> 31;
|
|
t6[6] = t4[6] << 1 | t4[5] >> 31;
|
|
t6[5] = t4[5] << 1 | t4[4] >> 31;
|
|
t6[4] = t4[4] << 1 | t4[3] >> 31;
|
|
t6[3] = t4[3] << 1 | t4[2] >> 31;
|
|
t6[2] = t4[2] << 1 | t4[1] >> 31;
|
|
t6[1] = t4[1] << 1 | t4[0] >> 31;
|
|
t6[0] = t4[0] << 1;
|
|
|
|
// don't discard the most significant bit, it's important too!
|
|
|
|
if (t4[7] & 0x80000000)
|
|
{
|
|
// use most significant bit and perform mod P, since we have: t4 * 2 % P
|
|
|
|
u32 a[8] = { 0 };
|
|
|
|
a[1] = 1;
|
|
a[0] = 0x000003d1; // omega (see: mul_mod ())
|
|
|
|
add (t6, t6, a);
|
|
}
|
|
|
|
mul_mod (t5, t7, t7); // t5 = t7*t7
|
|
|
|
sub_mod (t5, t5, t6); // t5 = t5-t6
|
|
sub_mod (t5, t5, t9); // t5 = t5-t9
|
|
sub_mod (t4, t4, t5); // t4 = t4-t5
|
|
|
|
mul_mod (t4, t4, t7); // t4 = t4*t7
|
|
mul_mod (t9, t9, t2); // t9 = t9*t2
|
|
|
|
sub_mod (t9, t4, t9); // t9 = t4-t9
|
|
|
|
x1[0] = t5[0];
|
|
x1[1] = t5[1];
|
|
x1[2] = t5[2];
|
|
x1[3] = t5[3];
|
|
x1[4] = t5[4];
|
|
x1[5] = t5[5];
|
|
x1[6] = t5[6];
|
|
x1[7] = t5[7];
|
|
|
|
y1[0] = t9[0];
|
|
y1[1] = t9[1];
|
|
y1[2] = t9[2];
|
|
y1[3] = t9[3];
|
|
y1[4] = t9[4];
|
|
y1[5] = t9[5];
|
|
y1[6] = t9[6];
|
|
y1[7] = t9[7];
|
|
|
|
z1[0] = t8[0];
|
|
z1[1] = t8[1];
|
|
z1[2] = t8[2];
|
|
z1[3] = t8[3];
|
|
z1[4] = t8[4];
|
|
z1[5] = t8[5];
|
|
z1[6] = t8[6];
|
|
z1[7] = t8[7];
|
|
}
|
|
|
|
DECLSPEC void point_get_coords (secp256k1_t *r, const u32 *x, const u32 *y)
|
|
{
|
|
/*
|
|
pre-compute 1/-1, 3/-3, 5/-5, 7/-7 times P (x, y)
|
|
for wNAF with window size 4 (max/min: +/- 2^3-1): -7, -5, -3, -1, 1, 3, 5, 7
|
|
|
|
+x1 ( 0)
|
|
+y1 ( 8)
|
|
-y1 (16)
|
|
|
|
+x3 (24)
|
|
+y3 (32)
|
|
-y3 (40)
|
|
|
|
+x5 (48)
|
|
+y5 (56)
|
|
-y5 (64)
|
|
|
|
+x7 (72)
|
|
+y7 (80)
|
|
-y7 (88)
|
|
*/
|
|
|
|
// note: we use jacobian forms with (x, y, z) for computation, but affine
|
|
// (or just converted to z = 1) for storage
|
|
|
|
// 1:
|
|
|
|
r->xy[ 0] = x[0];
|
|
r->xy[ 1] = x[1];
|
|
r->xy[ 2] = x[2];
|
|
r->xy[ 3] = x[3];
|
|
r->xy[ 4] = x[4];
|
|
r->xy[ 5] = x[5];
|
|
r->xy[ 6] = x[6];
|
|
r->xy[ 7] = x[7];
|
|
|
|
r->xy[ 8] = y[0];
|
|
r->xy[ 9] = y[1];
|
|
r->xy[10] = y[2];
|
|
r->xy[11] = y[3];
|
|
r->xy[12] = y[4];
|
|
r->xy[13] = y[5];
|
|
r->xy[14] = y[6];
|
|
r->xy[15] = y[7];
|
|
|
|
// -1:
|
|
|
|
u32 p[8];
|
|
|
|
p[0] = SECP256K1_P0;
|
|
p[1] = SECP256K1_P1;
|
|
p[2] = SECP256K1_P2;
|
|
p[3] = SECP256K1_P3;
|
|
p[4] = SECP256K1_P4;
|
|
p[5] = SECP256K1_P5;
|
|
p[6] = SECP256K1_P6;
|
|
p[7] = SECP256K1_P7;
|
|
|
|
u32 neg[8];
|
|
|
|
neg[0] = y[0];
|
|
neg[1] = y[1];
|
|
neg[2] = y[2];
|
|
neg[3] = y[3];
|
|
neg[4] = y[4];
|
|
neg[5] = y[5];
|
|
neg[6] = y[6];
|
|
neg[7] = y[7];
|
|
|
|
sub_mod (neg, p, neg); // -y = p - y
|
|
|
|
r->xy[16] = neg[0];
|
|
r->xy[17] = neg[1];
|
|
r->xy[18] = neg[2];
|
|
r->xy[19] = neg[3];
|
|
r->xy[20] = neg[4];
|
|
r->xy[21] = neg[5];
|
|
r->xy[22] = neg[6];
|
|
r->xy[23] = neg[7];
|
|
|
|
|
|
// copy of 1:
|
|
|
|
u32 tx[8];
|
|
|
|
tx[0] = x[0];
|
|
tx[1] = x[1];
|
|
tx[2] = x[2];
|
|
tx[3] = x[3];
|
|
tx[4] = x[4];
|
|
tx[5] = x[5];
|
|
tx[6] = x[6];
|
|
tx[7] = x[7];
|
|
|
|
u32 ty[8];
|
|
|
|
ty[0] = y[0];
|
|
ty[1] = y[1];
|
|
ty[2] = y[2];
|
|
ty[3] = y[3];
|
|
ty[4] = y[4];
|
|
ty[5] = y[5];
|
|
ty[6] = y[6];
|
|
ty[7] = y[7];
|
|
|
|
u32 rx[8];
|
|
|
|
rx[0] = x[0];
|
|
rx[1] = x[1];
|
|
rx[2] = x[2];
|
|
rx[3] = x[3];
|
|
rx[4] = x[4];
|
|
rx[5] = x[5];
|
|
rx[6] = x[6];
|
|
rx[7] = x[7];
|
|
|
|
u32 ry[8];
|
|
|
|
ry[0] = y[0];
|
|
ry[1] = y[1];
|
|
ry[2] = y[2];
|
|
ry[3] = y[3];
|
|
ry[4] = y[4];
|
|
ry[5] = y[5];
|
|
ry[6] = y[6];
|
|
ry[7] = y[7];
|
|
|
|
u32 rz[8] = { 0 };
|
|
|
|
rz[0] = 1;
|
|
|
|
|
|
// 3:
|
|
|
|
point_double (rx, ry, rz); // 2
|
|
point_add (rx, ry, rz, tx, ty); // 3
|
|
|
|
// to affine:
|
|
|
|
inv_mod (rz);
|
|
|
|
mul_mod (neg, rz, rz); // neg is temporary variable (z^2)
|
|
mul_mod (rx, rx, neg);
|
|
|
|
mul_mod (rz, neg, rz);
|
|
mul_mod (ry, ry, rz);
|
|
|
|
r->xy[24] = rx[0];
|
|
r->xy[25] = rx[1];
|
|
r->xy[26] = rx[2];
|
|
r->xy[27] = rx[3];
|
|
r->xy[28] = rx[4];
|
|
r->xy[29] = rx[5];
|
|
r->xy[30] = rx[6];
|
|
r->xy[31] = rx[7];
|
|
|
|
r->xy[32] = ry[0];
|
|
r->xy[33] = ry[1];
|
|
r->xy[34] = ry[2];
|
|
r->xy[35] = ry[3];
|
|
r->xy[36] = ry[4];
|
|
r->xy[37] = ry[5];
|
|
r->xy[38] = ry[6];
|
|
r->xy[39] = ry[7];
|
|
|
|
// -3:
|
|
|
|
neg[0] = ry[0];
|
|
neg[1] = ry[1];
|
|
neg[2] = ry[2];
|
|
neg[3] = ry[3];
|
|
neg[4] = ry[4];
|
|
neg[5] = ry[5];
|
|
neg[6] = ry[6];
|
|
neg[7] = ry[7];
|
|
|
|
sub_mod (neg, p, neg);
|
|
|
|
r->xy[40] = neg[0];
|
|
r->xy[41] = neg[1];
|
|
r->xy[42] = neg[2];
|
|
r->xy[43] = neg[3];
|
|
r->xy[44] = neg[4];
|
|
r->xy[45] = neg[5];
|
|
r->xy[46] = neg[6];
|
|
r->xy[47] = neg[7];
|
|
|
|
|
|
// 5:
|
|
|
|
rz[0] = 1; // actually we could take advantage of rz being 1 too (alternative point_add ()),
|
|
rz[1] = 0; // but it is not important because this is performed only once per "hash"
|
|
rz[2] = 0;
|
|
rz[3] = 0;
|
|
rz[4] = 0;
|
|
rz[5] = 0;
|
|
rz[6] = 0;
|
|
rz[7] = 0;
|
|
|
|
point_add (rx, ry, rz, tx, ty); // 4
|
|
point_add (rx, ry, rz, tx, ty); // 5
|
|
|
|
// to affine:
|
|
|
|
inv_mod (rz);
|
|
|
|
mul_mod (neg, rz, rz);
|
|
mul_mod (rx, rx, neg);
|
|
|
|
mul_mod (rz, neg, rz);
|
|
mul_mod (ry, ry, rz);
|
|
|
|
r->xy[48] = rx[0];
|
|
r->xy[49] = rx[1];
|
|
r->xy[50] = rx[2];
|
|
r->xy[51] = rx[3];
|
|
r->xy[52] = rx[4];
|
|
r->xy[53] = rx[5];
|
|
r->xy[54] = rx[6];
|
|
r->xy[55] = rx[7];
|
|
|
|
r->xy[56] = ry[0];
|
|
r->xy[57] = ry[1];
|
|
r->xy[58] = ry[2];
|
|
r->xy[59] = ry[3];
|
|
r->xy[60] = ry[4];
|
|
r->xy[61] = ry[5];
|
|
r->xy[62] = ry[6];
|
|
r->xy[63] = ry[7];
|
|
|
|
// -5:
|
|
|
|
neg[0] = ry[0];
|
|
neg[1] = ry[1];
|
|
neg[2] = ry[2];
|
|
neg[3] = ry[3];
|
|
neg[4] = ry[4];
|
|
neg[5] = ry[5];
|
|
neg[6] = ry[6];
|
|
neg[7] = ry[7];
|
|
|
|
sub_mod (neg, p, neg);
|
|
|
|
r->xy[64] = neg[0];
|
|
r->xy[65] = neg[1];
|
|
r->xy[66] = neg[2];
|
|
r->xy[67] = neg[3];
|
|
r->xy[68] = neg[4];
|
|
r->xy[69] = neg[5];
|
|
r->xy[70] = neg[6];
|
|
r->xy[71] = neg[7];
|
|
|
|
|
|
// 7:
|
|
|
|
rz[0] = 1;
|
|
rz[1] = 0;
|
|
rz[2] = 0;
|
|
rz[3] = 0;
|
|
rz[4] = 0;
|
|
rz[5] = 0;
|
|
rz[6] = 0;
|
|
rz[7] = 0;
|
|
|
|
point_add (rx, ry, rz, tx, ty); // 6
|
|
point_add (rx, ry, rz, tx, ty); // 7
|
|
|
|
// to affine:
|
|
|
|
inv_mod (rz);
|
|
|
|
mul_mod (neg, rz, rz);
|
|
mul_mod (rx, rx, neg);
|
|
|
|
mul_mod (rz, neg, rz);
|
|
mul_mod (ry, ry, rz);
|
|
|
|
r->xy[72] = rx[0];
|
|
r->xy[73] = rx[1];
|
|
r->xy[74] = rx[2];
|
|
r->xy[75] = rx[3];
|
|
r->xy[76] = rx[4];
|
|
r->xy[77] = rx[5];
|
|
r->xy[78] = rx[6];
|
|
r->xy[79] = rx[7];
|
|
|
|
r->xy[80] = ry[0];
|
|
r->xy[81] = ry[1];
|
|
r->xy[82] = ry[2];
|
|
r->xy[83] = ry[3];
|
|
r->xy[84] = ry[4];
|
|
r->xy[85] = ry[5];
|
|
r->xy[86] = ry[6];
|
|
r->xy[87] = ry[7];
|
|
|
|
// -7:
|
|
|
|
neg[0] = ry[0];
|
|
neg[1] = ry[1];
|
|
neg[2] = ry[2];
|
|
neg[3] = ry[3];
|
|
neg[4] = ry[4];
|
|
neg[5] = ry[5];
|
|
neg[6] = ry[6];
|
|
neg[7] = ry[7];
|
|
|
|
sub_mod (neg, p, neg);
|
|
|
|
r->xy[88] = neg[0];
|
|
r->xy[89] = neg[1];
|
|
r->xy[90] = neg[2];
|
|
r->xy[91] = neg[3];
|
|
r->xy[92] = neg[4];
|
|
r->xy[93] = neg[5];
|
|
r->xy[94] = neg[6];
|
|
r->xy[95] = neg[7];
|
|
}
|
|
|
|
/*
|
|
* Convert the tweak/scalar k to w-NAF (window size is 4).
|
|
* @param naf out: w-NAF form of the tweak/scalar, a pointer to an u32 array with a size of 33.
|
|
* @param k in: tweak/scalar which should be converted, a pointer to an u32 array with a size of 8.
|
|
* @return Returns the loop start index.
|
|
*/
|
|
DECLSPEC int convert_to_window_naf (u32 *naf, const u32 *k)
|
|
{
|
|
int loop_start = 0;
|
|
u32 n[9];
|
|
n[0] = 0; // we need this extra slot sometimes for the subtraction to work
|
|
n[1] = k[7];
|
|
n[2] = k[6];
|
|
n[3] = k[5];
|
|
n[4] = k[4];
|
|
n[5] = k[3];
|
|
n[6] = k[2];
|
|
n[7] = k[1];
|
|
n[8] = k[0];
|
|
|
|
for (int i = 0; i <= 256; i++)
|
|
{
|
|
if (n[8] & 1)
|
|
{
|
|
// for window size w = 4:
|
|
// => 2^(w-0) = 2^4 = 16 (0x10)
|
|
// => 2^(w-1) = 2^3 = 8 (0x08)
|
|
|
|
int diff = n[8] & 0x0f; // n % 2^w == n & (2^w - 1)
|
|
|
|
// convert diff to val according to this table:
|
|
// 1 -> +1 -> 1
|
|
// 3 -> +3 -> 3
|
|
// 5 -> +5 -> 5
|
|
// 7 -> +7 -> 7
|
|
// 9 -> -7 -> 8
|
|
// 11 -> -5 -> 6
|
|
// 13 -> -3 -> 4
|
|
// 15 -> -1 -> 2
|
|
|
|
int val = diff;
|
|
|
|
if (diff >= 0x08)
|
|
{
|
|
diff -= 0x10;
|
|
|
|
val = 0x11 - val;
|
|
}
|
|
|
|
naf[i >> 3] |= val << ((i & 7) << 2);
|
|
|
|
u32 t = n[8]; // t is the (temporary) old/unmodified value
|
|
|
|
n[8] -= diff;
|
|
|
|
// we need to take care of the carry/borrow:
|
|
|
|
u32 k = 8;
|
|
|
|
if (diff > 0)
|
|
{
|
|
while (n[k] > t) // overflow propagation
|
|
{
|
|
if (k == 0) break; // needed ?
|
|
|
|
k--;
|
|
|
|
t = n[k];
|
|
|
|
n[k]--;
|
|
}
|
|
}
|
|
else // if (diff < 0)
|
|
{
|
|
while (t > n[k]) // overflow propagation
|
|
{
|
|
if (k == 0) break;
|
|
|
|
k--;
|
|
|
|
t = n[k];
|
|
|
|
n[k]++;
|
|
}
|
|
}
|
|
|
|
// update start:
|
|
|
|
loop_start = i;
|
|
}
|
|
|
|
// n = n / 2:
|
|
|
|
n[8] = n[8] >> 1 | n[7] << 31;
|
|
n[7] = n[7] >> 1 | n[6] << 31;
|
|
n[6] = n[6] >> 1 | n[5] << 31;
|
|
n[5] = n[5] >> 1 | n[4] << 31;
|
|
n[4] = n[4] >> 1 | n[3] << 31;
|
|
n[3] = n[3] >> 1 | n[2] << 31;
|
|
n[2] = n[2] >> 1 | n[1] << 31;
|
|
n[1] = n[1] >> 1 | n[0] << 31;
|
|
n[0] = n[0] >> 1;
|
|
}
|
|
return loop_start;
|
|
}
|
|
|
|
/*
|
|
* @param x1 out: x coordinate, a pointer to an u32 array with a size of 8.
|
|
* @param y1 out: y coordinate, a pointer to an u32 array with a size of 8.
|
|
* @param k in: tweak/scalar which should be converted, a pointer to an u32 array with a size of 8.
|
|
* @param tmps in: a basepoint for the multiplication.
|
|
* @return Returns the x coordinate with a leading parity/sign (for odd/even y), it is named a compressed coordinate.
|
|
*/
|
|
DECLSPEC void point_mul_xy (u32 *x1, u32 *y1, const u32 *k, GLOBAL_AS const secp256k1_t *tmps)
|
|
{
|
|
u32 naf[SECP256K1_NAF_SIZE] = { 0 };
|
|
int loop_start = convert_to_window_naf(naf, k);
|
|
|
|
// first set:
|
|
|
|
const u32 multiplier = (naf[loop_start >> 3] >> ((loop_start & 7) << 2)) & 0x0f; // or use u8 ?
|
|
|
|
const u32 odd = multiplier & 1;
|
|
|
|
const u32 x_pos = ((multiplier - 1 + odd) >> 1) * 24;
|
|
const u32 y_pos = odd ? (x_pos + 8) : (x_pos + 16);
|
|
|
|
|
|
x1[0] = tmps->xy[x_pos + 0];
|
|
x1[1] = tmps->xy[x_pos + 1];
|
|
x1[2] = tmps->xy[x_pos + 2];
|
|
x1[3] = tmps->xy[x_pos + 3];
|
|
x1[4] = tmps->xy[x_pos + 4];
|
|
x1[5] = tmps->xy[x_pos + 5];
|
|
x1[6] = tmps->xy[x_pos + 6];
|
|
x1[7] = tmps->xy[x_pos + 7];
|
|
|
|
y1[0] = tmps->xy[y_pos + 0];
|
|
y1[1] = tmps->xy[y_pos + 1];
|
|
y1[2] = tmps->xy[y_pos + 2];
|
|
y1[3] = tmps->xy[y_pos + 3];
|
|
y1[4] = tmps->xy[y_pos + 4];
|
|
y1[5] = tmps->xy[y_pos + 5];
|
|
y1[6] = tmps->xy[y_pos + 6];
|
|
y1[7] = tmps->xy[y_pos + 7];
|
|
|
|
u32 z1[8] = { 0 };
|
|
|
|
z1[0] = 1;
|
|
|
|
/*
|
|
* Start:
|
|
*/
|
|
|
|
// main loop (left-to-right binary algorithm):
|
|
|
|
for (int pos = loop_start - 1; pos >= 0; pos--) // -1 because we've set/add the point already
|
|
{
|
|
// always double:
|
|
|
|
point_double (x1, y1, z1);
|
|
|
|
// add only if needed:
|
|
|
|
const u32 multiplier = (naf[pos >> 3] >> ((pos & 7) << 2)) & 0x0f;
|
|
|
|
if (multiplier)
|
|
{
|
|
/*
|
|
m -> y | y = ((m - (m & 1)) / 2) * 24
|
|
----------------------------------
|
|
1 -> 0 | 1/2 * 24 = 0
|
|
2 -> 16
|
|
3 -> 24 | 3/2 * 24 = 24
|
|
4 -> 40
|
|
5 -> 48 | 5/2 * 24 = 2*24
|
|
6 -> 64
|
|
7 -> 72 | 7/2 * 24 = 3*24
|
|
8 -> 88
|
|
*/
|
|
|
|
const u32 odd = multiplier & 1;
|
|
|
|
const u32 x_pos = ((multiplier - 1 + odd) >> 1) * 24;
|
|
const u32 y_pos = odd ? (x_pos + 8) : (x_pos + 16);
|
|
|
|
u32 x2[8];
|
|
|
|
x2[0] = tmps->xy[x_pos + 0];
|
|
x2[1] = tmps->xy[x_pos + 1];
|
|
x2[2] = tmps->xy[x_pos + 2];
|
|
x2[3] = tmps->xy[x_pos + 3];
|
|
x2[4] = tmps->xy[x_pos + 4];
|
|
x2[5] = tmps->xy[x_pos + 5];
|
|
x2[6] = tmps->xy[x_pos + 6];
|
|
x2[7] = tmps->xy[x_pos + 7];
|
|
|
|
u32 y2[8];
|
|
|
|
y2[0] = tmps->xy[y_pos + 0];
|
|
y2[1] = tmps->xy[y_pos + 1];
|
|
y2[2] = tmps->xy[y_pos + 2];
|
|
y2[3] = tmps->xy[y_pos + 3];
|
|
y2[4] = tmps->xy[y_pos + 4];
|
|
y2[5] = tmps->xy[y_pos + 5];
|
|
y2[6] = tmps->xy[y_pos + 6];
|
|
y2[7] = tmps->xy[y_pos + 7];
|
|
|
|
// (x1, y1, z1) + multiplier * (x, y, z) = (x1, y1, z1) + (x2, y2, z2)
|
|
|
|
point_add (x1, y1, z1, x2, y2);
|
|
|
|
// optimization (there can't be any adds after an add for w-1 times):
|
|
// (but it seems to be faster without this manipulation of "pos")
|
|
|
|
//for (u32 i = 0; i < 3; i++)
|
|
//{
|
|
// if (pos == 0) break;
|
|
// point_double (x1, y1, z1);
|
|
// pos--;
|
|
//}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Get the corresponding affine coordinates x/y:
|
|
*
|
|
* Note:
|
|
* x1_affine = x1_jacobian / z1^2 = x1_jacobian * z1_inv^2
|
|
* y1_affine = y1_jacobian / z1^2 = y1_jacobian * z1_inv^2
|
|
*
|
|
*/
|
|
|
|
inv_mod (z1);
|
|
|
|
u32 z2[8];
|
|
|
|
mul_mod (z2, z1, z1); // z1^2
|
|
mul_mod (x1, x1, z2); // x1_affine
|
|
|
|
mul_mod (z1, z2, z1); // z1^3
|
|
mul_mod (y1, y1, z1); // y1_affine
|
|
|
|
// return values are already in x1 and y1
|
|
}
|
|
|
|
/*
|
|
* @param r out: x coordinate with leading parity/sign (for odd/even y), a pointer to an u32 array with a size of 9.
|
|
* @param k in: tweak/scalar which should be converted, a pointer to an u32 array with a size of 8.
|
|
* @param tmps in: a basepoint for the multiplication.
|
|
* @return Returns the x coordinate with a leading parity/sign (for odd/even y), it is named a compressed coordinate.
|
|
*/
|
|
DECLSPEC void point_mul (u32 *r, const u32 *k, GLOBAL_AS const secp256k1_t *tmps)
|
|
{
|
|
u32 x[8];
|
|
u32 y[8];
|
|
point_mul_xy(x, y, k, tmps);
|
|
|
|
/*
|
|
* output:
|
|
*/
|
|
|
|
// shift by 1 byte (8 bits) to make room and add the parity/sign (for odd/even y):
|
|
|
|
r[8] = (x[0] << 24);
|
|
r[7] = (x[0] >> 8) | (x[1] << 24);
|
|
r[6] = (x[1] >> 8) | (x[2] << 24);
|
|
r[5] = (x[2] >> 8) | (x[3] << 24);
|
|
r[4] = (x[3] >> 8) | (x[4] << 24);
|
|
r[3] = (x[4] >> 8) | (x[5] << 24);
|
|
r[2] = (x[5] >> 8) | (x[6] << 24);
|
|
r[1] = (x[6] >> 8) | (x[7] << 24);
|
|
r[0] = (x[7] >> 8);
|
|
|
|
const u32 type = 0x02 | (y[0] & 1); // (note: 0b10 | 0b01 = 0x03)
|
|
|
|
r[0] = r[0] | type << 24; // 0x02 or 0x03
|
|
}
|
|
|
|
/*
|
|
* Transform a x coordinate and separate parity to secp256k1_t.
|
|
* @param r out: x and y coordinates.
|
|
* @param x in: x coordinate which should be converted, a pointer to an u32 array with a size of 8.
|
|
* @param first_byte in: The parity of the y coordinate, a u32.
|
|
* @return Returns 0 if successfull, returns 1 if x is greater than the basepoint.
|
|
*/
|
|
DECLSPEC u32 transform_public (secp256k1_t *r, const u32 *x, const u32 first_byte)
|
|
{
|
|
u32 p[8];
|
|
|
|
p[0] = SECP256K1_P0;
|
|
p[1] = SECP256K1_P1;
|
|
p[2] = SECP256K1_P2;
|
|
p[3] = SECP256K1_P3;
|
|
p[4] = SECP256K1_P4;
|
|
p[5] = SECP256K1_P5;
|
|
p[6] = SECP256K1_P6;
|
|
p[7] = SECP256K1_P7;
|
|
|
|
// x must be smaller than p (because of y ^ 2 = x ^ 3 % p)
|
|
|
|
for (int i = 7; i >= 0; i--)
|
|
{
|
|
if (x[i] < p[i]) break;
|
|
if (x[i] > p[i]) return 1;
|
|
}
|
|
|
|
|
|
// get y^2 = x^3 + 7:
|
|
|
|
u32 b[8] = { 0 };
|
|
|
|
b[0] = SECP256K1_B;
|
|
|
|
u32 y[8];
|
|
|
|
mul_mod (y, x, x);
|
|
mul_mod (y, y, x);
|
|
add_mod (y, y, b);
|
|
|
|
// get y = sqrt (y^2):
|
|
|
|
sqrt_mod (y);
|
|
|
|
// check if it's of the correct parity that we want (odd/even):
|
|
|
|
if ((first_byte & 1) != (y[0] & 1))
|
|
{
|
|
// y2 = p - y1 (or y2 = y1 * -1)
|
|
|
|
sub_mod (y, p, y);
|
|
}
|
|
|
|
// get xy:
|
|
|
|
point_get_coords (r, x, y);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Parse a x coordinate with leading parity to secp256k1_t.
|
|
* @param r out: x and y coordinates.
|
|
* @param k in: x coordinate which should be converted with leading parity, a pointer to an u32 array with a size of 9.
|
|
* @return Returns 0 if successfull, returns 1 if x is greater than the basepoint or the parity has an unexpected value.
|
|
*/
|
|
DECLSPEC u32 parse_public (secp256k1_t *r, const u32 *k)
|
|
{
|
|
// verify:
|
|
|
|
const u32 first_byte = k[0] & 0xff;
|
|
|
|
if ((first_byte != '\x02') && (first_byte != '\x03'))
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
// load k into x without the first byte:
|
|
|
|
u32 x[8];
|
|
|
|
x[0] = (k[7] & 0xff00) << 16 | (k[7] & 0xff0000) | (k[7] & 0xff000000) >> 16 | (k[8] & 0xff);
|
|
x[1] = (k[6] & 0xff00) << 16 | (k[6] & 0xff0000) | (k[6] & 0xff000000) >> 16 | (k[7] & 0xff);
|
|
x[2] = (k[5] & 0xff00) << 16 | (k[5] & 0xff0000) | (k[5] & 0xff000000) >> 16 | (k[6] & 0xff);
|
|
x[3] = (k[4] & 0xff00) << 16 | (k[4] & 0xff0000) | (k[4] & 0xff000000) >> 16 | (k[5] & 0xff);
|
|
x[4] = (k[3] & 0xff00) << 16 | (k[3] & 0xff0000) | (k[3] & 0xff000000) >> 16 | (k[4] & 0xff);
|
|
x[5] = (k[2] & 0xff00) << 16 | (k[2] & 0xff0000) | (k[2] & 0xff000000) >> 16 | (k[3] & 0xff);
|
|
x[6] = (k[1] & 0xff00) << 16 | (k[1] & 0xff0000) | (k[1] & 0xff000000) >> 16 | (k[2] & 0xff);
|
|
x[7] = (k[0] & 0xff00) << 16 | (k[0] & 0xff0000) | (k[0] & 0xff000000) >> 16 | (k[1] & 0xff);
|
|
|
|
return transform_public(r, x, first_byte);
|
|
}
|
|
|
|
|
|
/*
|
|
* Set precomputed values of the basepoint g to a secp256k1 structure.
|
|
* @param r out: x and y coordinates. pre-computed points: (x1,y1,-y1),(x3,y3,-y3),(x5,y5,-y5),(x7,y7,-y7)
|
|
*/
|
|
DECLSPEC void set_precomputed_basepoint_g (secp256k1_t *r) {
|
|
// x1
|
|
r->xy[ 0] = SECP256K1_G_PRE_COMPUTED_00;
|
|
r->xy[ 1] = SECP256K1_G_PRE_COMPUTED_01;
|
|
r->xy[ 2] = SECP256K1_G_PRE_COMPUTED_02;
|
|
r->xy[ 3] = SECP256K1_G_PRE_COMPUTED_03;
|
|
r->xy[ 4] = SECP256K1_G_PRE_COMPUTED_04;
|
|
r->xy[ 5] = SECP256K1_G_PRE_COMPUTED_05;
|
|
r->xy[ 6] = SECP256K1_G_PRE_COMPUTED_06;
|
|
r->xy[ 7] = SECP256K1_G_PRE_COMPUTED_07;
|
|
|
|
// y1
|
|
r->xy[ 8] = SECP256K1_G_PRE_COMPUTED_08;
|
|
r->xy[ 9] = SECP256K1_G_PRE_COMPUTED_09;
|
|
r->xy[10] = SECP256K1_G_PRE_COMPUTED_10;
|
|
r->xy[11] = SECP256K1_G_PRE_COMPUTED_11;
|
|
r->xy[12] = SECP256K1_G_PRE_COMPUTED_12;
|
|
r->xy[13] = SECP256K1_G_PRE_COMPUTED_13;
|
|
r->xy[14] = SECP256K1_G_PRE_COMPUTED_14;
|
|
r->xy[15] = SECP256K1_G_PRE_COMPUTED_15;
|
|
|
|
// -y1
|
|
r->xy[16] = SECP256K1_G_PRE_COMPUTED_16;
|
|
r->xy[17] = SECP256K1_G_PRE_COMPUTED_17;
|
|
r->xy[18] = SECP256K1_G_PRE_COMPUTED_18;
|
|
r->xy[19] = SECP256K1_G_PRE_COMPUTED_19;
|
|
r->xy[20] = SECP256K1_G_PRE_COMPUTED_20;
|
|
r->xy[21] = SECP256K1_G_PRE_COMPUTED_21;
|
|
r->xy[22] = SECP256K1_G_PRE_COMPUTED_22;
|
|
r->xy[23] = SECP256K1_G_PRE_COMPUTED_23;
|
|
|
|
// x3
|
|
r->xy[24] = SECP256K1_G_PRE_COMPUTED_24;
|
|
r->xy[25] = SECP256K1_G_PRE_COMPUTED_25;
|
|
r->xy[26] = SECP256K1_G_PRE_COMPUTED_26;
|
|
r->xy[27] = SECP256K1_G_PRE_COMPUTED_27;
|
|
r->xy[28] = SECP256K1_G_PRE_COMPUTED_28;
|
|
r->xy[29] = SECP256K1_G_PRE_COMPUTED_29;
|
|
r->xy[30] = SECP256K1_G_PRE_COMPUTED_30;
|
|
r->xy[31] = SECP256K1_G_PRE_COMPUTED_31;
|
|
|
|
// y3
|
|
r->xy[32] = SECP256K1_G_PRE_COMPUTED_32;
|
|
r->xy[33] = SECP256K1_G_PRE_COMPUTED_33;
|
|
r->xy[34] = SECP256K1_G_PRE_COMPUTED_34;
|
|
r->xy[35] = SECP256K1_G_PRE_COMPUTED_35;
|
|
r->xy[36] = SECP256K1_G_PRE_COMPUTED_36;
|
|
r->xy[37] = SECP256K1_G_PRE_COMPUTED_37;
|
|
r->xy[38] = SECP256K1_G_PRE_COMPUTED_38;
|
|
r->xy[39] = SECP256K1_G_PRE_COMPUTED_39;
|
|
|
|
// -y3
|
|
r->xy[40] = SECP256K1_G_PRE_COMPUTED_40;
|
|
r->xy[41] = SECP256K1_G_PRE_COMPUTED_41;
|
|
r->xy[42] = SECP256K1_G_PRE_COMPUTED_42;
|
|
r->xy[43] = SECP256K1_G_PRE_COMPUTED_43;
|
|
r->xy[44] = SECP256K1_G_PRE_COMPUTED_44;
|
|
r->xy[45] = SECP256K1_G_PRE_COMPUTED_45;
|
|
r->xy[46] = SECP256K1_G_PRE_COMPUTED_46;
|
|
r->xy[47] = SECP256K1_G_PRE_COMPUTED_47;
|
|
|
|
// x5
|
|
r->xy[48] = SECP256K1_G_PRE_COMPUTED_48;
|
|
r->xy[49] = SECP256K1_G_PRE_COMPUTED_49;
|
|
r->xy[50] = SECP256K1_G_PRE_COMPUTED_50;
|
|
r->xy[51] = SECP256K1_G_PRE_COMPUTED_51;
|
|
r->xy[52] = SECP256K1_G_PRE_COMPUTED_52;
|
|
r->xy[53] = SECP256K1_G_PRE_COMPUTED_53;
|
|
r->xy[54] = SECP256K1_G_PRE_COMPUTED_54;
|
|
r->xy[55] = SECP256K1_G_PRE_COMPUTED_55;
|
|
|
|
// y5
|
|
r->xy[56] = SECP256K1_G_PRE_COMPUTED_56;
|
|
r->xy[57] = SECP256K1_G_PRE_COMPUTED_57;
|
|
r->xy[58] = SECP256K1_G_PRE_COMPUTED_58;
|
|
r->xy[59] = SECP256K1_G_PRE_COMPUTED_59;
|
|
r->xy[60] = SECP256K1_G_PRE_COMPUTED_60;
|
|
r->xy[61] = SECP256K1_G_PRE_COMPUTED_61;
|
|
r->xy[62] = SECP256K1_G_PRE_COMPUTED_62;
|
|
r->xy[63] = SECP256K1_G_PRE_COMPUTED_63;
|
|
|
|
// -y5
|
|
r->xy[64] = SECP256K1_G_PRE_COMPUTED_64;
|
|
r->xy[65] = SECP256K1_G_PRE_COMPUTED_65;
|
|
r->xy[66] = SECP256K1_G_PRE_COMPUTED_66;
|
|
r->xy[67] = SECP256K1_G_PRE_COMPUTED_67;
|
|
r->xy[68] = SECP256K1_G_PRE_COMPUTED_68;
|
|
r->xy[69] = SECP256K1_G_PRE_COMPUTED_69;
|
|
r->xy[70] = SECP256K1_G_PRE_COMPUTED_70;
|
|
r->xy[71] = SECP256K1_G_PRE_COMPUTED_71;
|
|
|
|
// x7
|
|
r->xy[72] = SECP256K1_G_PRE_COMPUTED_72;
|
|
r->xy[73] = SECP256K1_G_PRE_COMPUTED_73;
|
|
r->xy[74] = SECP256K1_G_PRE_COMPUTED_74;
|
|
r->xy[75] = SECP256K1_G_PRE_COMPUTED_75;
|
|
r->xy[76] = SECP256K1_G_PRE_COMPUTED_76;
|
|
r->xy[77] = SECP256K1_G_PRE_COMPUTED_77;
|
|
r->xy[78] = SECP256K1_G_PRE_COMPUTED_78;
|
|
r->xy[79] = SECP256K1_G_PRE_COMPUTED_79;
|
|
|
|
// y7
|
|
r->xy[80] = SECP256K1_G_PRE_COMPUTED_80;
|
|
r->xy[81] = SECP256K1_G_PRE_COMPUTED_81;
|
|
r->xy[82] = SECP256K1_G_PRE_COMPUTED_82;
|
|
r->xy[83] = SECP256K1_G_PRE_COMPUTED_83;
|
|
r->xy[84] = SECP256K1_G_PRE_COMPUTED_84;
|
|
r->xy[85] = SECP256K1_G_PRE_COMPUTED_85;
|
|
r->xy[86] = SECP256K1_G_PRE_COMPUTED_86;
|
|
r->xy[87] = SECP256K1_G_PRE_COMPUTED_87;
|
|
|
|
// -y7
|
|
r->xy[88] = SECP256K1_G_PRE_COMPUTED_88;
|
|
r->xy[89] = SECP256K1_G_PRE_COMPUTED_89;
|
|
r->xy[90] = SECP256K1_G_PRE_COMPUTED_90;
|
|
r->xy[91] = SECP256K1_G_PRE_COMPUTED_91;
|
|
r->xy[92] = SECP256K1_G_PRE_COMPUTED_92;
|
|
r->xy[93] = SECP256K1_G_PRE_COMPUTED_93;
|
|
r->xy[94] = SECP256K1_G_PRE_COMPUTED_94;
|
|
r->xy[95] = SECP256K1_G_PRE_COMPUTED_95;
|
|
}
|