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// Copyright (c) 2016 Jack Grigg
// Copyright (c) 2016 The Zcash developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://www.opensource.org/licenses/mit-license.php .
// Implementation of the Equihash Proof-of-Work algorithm.
//
// Reference
// =========
// Alex Biryukov and Dmitry Khovratovich
// Equihash: Asymmetric Proof-of-Work Based on the Generalized Birthday Problem
// NDSS ’16, 21-24 February 2016, San Diego, CA, USA
// https://www.internetsociety.org/sites/default/files/blogs-media/equihash-asymmetric-proof-of-work-based-generalized-birthday-problem.pdf
#if defined(HAVE_CONFIG_H)
#include "config/bitcoin-config.h"
#endif
#include "compat/endian.h"
#include "crypto/equihash.h"
#include "util.h"
#include <algorithm>
#include <iostream>
#include <stdexcept>
#include <boost/optional.hpp>
static EhSolverCancelledException solver_cancelled;
template<unsigned int N, unsigned int K>
int Equihash<N,K>::InitialiseState(eh_HashState& base_state)
{
uint32_t le_N = htole32(N);
uint32_t le_K = htole32(K);
unsigned char personalization[crypto_generichash_blake2b_PERSONALBYTES] = {};
memcpy(personalization, "ZcashPoW", 8);
memcpy(personalization+8, &le_N, 4);
memcpy(personalization+12, &le_K, 4);
return crypto_generichash_blake2b_init_salt_personal(&base_state,
NULL, 0, // No key.
(512/N)*N/8,
NULL, // No salt.
personalization);
}
void GenerateHash(const eh_HashState& base_state, eh_index g,
unsigned char* hash, size_t hLen)
{
eh_HashState state;
state = base_state;
eh_index lei = htole32(g);
crypto_generichash_blake2b_update(&state, (const unsigned char*) &lei,
sizeof(eh_index));
crypto_generichash_blake2b_final(&state, hash, hLen);
}
void ExpandArray(const unsigned char* in, size_t in_len,
unsigned char* out, size_t out_len,
size_t bit_len, size_t byte_pad)
{
assert(bit_len >= 8);
assert(8*sizeof(uint32_t) >= 7+bit_len);
size_t out_width { (bit_len+7)/8 + byte_pad };
assert(out_len == 8*out_width*in_len/bit_len);
uint32_t bit_len_mask { ((uint32_t)1 << bit_len) - 1 };
// The acc_bits least-significant bits of acc_value represent a bit sequence
// in big-endian order.
size_t acc_bits = 0;
uint32_t acc_value = 0;
size_t j = 0;
for (size_t i = 0; i < in_len; i++) {
acc_value = (acc_value << 8) | in[i];
acc_bits += 8;
// When we have bit_len or more bits in the accumulator, write the next
// output element.
if (acc_bits >= bit_len) {
acc_bits -= bit_len;
for (size_t x = 0; x < byte_pad; x++) {
out[j+x] = 0;
}
for (size_t x = byte_pad; x < out_width; x++) {
out[j+x] = (
// Big-endian
acc_value >> (acc_bits+(8*(out_width-x-1)))
) & (
// Apply bit_len_mask across byte boundaries
(bit_len_mask >> (8*(out_width-x-1))) & 0xFF
);
}
j += out_width;
}
}
}
void CompressArray(const unsigned char* in, size_t in_len,
unsigned char* out, size_t out_len,
size_t bit_len, size_t byte_pad)
{
assert(bit_len >= 8);
assert(8*sizeof(uint32_t) >= 7+bit_len);
size_t in_width { (bit_len+7)/8 + byte_pad };
assert(out_len == bit_len*in_len/(8*in_width));
uint32_t bit_len_mask { ((uint32_t)1 << bit_len) - 1 };
// The acc_bits least-significant bits of acc_value represent a bit sequence
// in big-endian order.
size_t acc_bits = 0;
uint32_t acc_value = 0;
size_t j = 0;
for (size_t i = 0; i < out_len; i++) {
// When we have fewer than 8 bits left in the accumulator, read the next
// input element.
if (acc_bits < 8) {
acc_value = acc_value << bit_len;
for (size_t x = byte_pad; x < in_width; x++) {
acc_value = acc_value | (
(
// Apply bit_len_mask across byte boundaries
in[j+x] & ((bit_len_mask >> (8*(in_width-x-1))) & 0xFF)
) << (8*(in_width-x-1))); // Big-endian
}
j += in_width;
acc_bits += bit_len;
}
acc_bits -= 8;
out[i] = (acc_value >> acc_bits) & 0xFF;
}
}
// Big-endian so that lexicographic array comparison is equivalent to integer
// comparison
void EhIndexToArray(const eh_index i, unsigned char* array)
{
BOOST_STATIC_ASSERT(sizeof(eh_index) == 4);
eh_index bei = htobe32(i);
memcpy(array, &bei, sizeof(eh_index));
}
// Big-endian so that lexicographic array comparison is equivalent to integer
// comparison
eh_index ArrayToEhIndex(const unsigned char* array)
{
BOOST_STATIC_ASSERT(sizeof(eh_index) == 4);
eh_index bei;
memcpy(&bei, array, sizeof(eh_index));
return be32toh(bei);
}
eh_trunc TruncateIndex(const eh_index i, const unsigned int ilen)
{
// Truncate to 8 bits
BOOST_STATIC_ASSERT(sizeof(eh_trunc) == 1);
return (i >> (ilen - 8)) & 0xff;
}
eh_index UntruncateIndex(const eh_trunc t, const eh_index r, const unsigned int ilen)
{
eh_index i{t};
return (i << (ilen - 8)) | r;
}
std::vector<eh_index> GetIndicesFromMinimal(std::vector<unsigned char> minimal,
size_t cBitLen)
{
assert(((cBitLen+1)+7)/8 <= sizeof(eh_index));
size_t lenIndices { 8*sizeof(eh_index)*minimal.size()/(cBitLen+1) };
size_t bytePad { sizeof(eh_index) - ((cBitLen+1)+7)/8 };
std::vector<unsigned char> array(lenIndices);
ExpandArray(minimal.data(), minimal.size(),
array.data(), lenIndices, cBitLen+1, bytePad);
std::vector<eh_index> ret;
for (int i = 0; i < lenIndices; i += sizeof(eh_index)) {
ret.push_back(ArrayToEhIndex(array.data()+i));
}
return ret;
}
std::vector<unsigned char> GetMinimalFromIndices(std::vector<eh_index> indices,
size_t cBitLen)
{
assert(((cBitLen+1)+7)/8 <= sizeof(eh_index));
size_t lenIndices { indices.size()*sizeof(eh_index) };
size_t minLen { (cBitLen+1)*lenIndices/(8*sizeof(eh_index)) };
size_t bytePad { sizeof(eh_index) - ((cBitLen+1)+7)/8 };
std::vector<unsigned char> array(lenIndices);
for (int i = 0; i < indices.size(); i++) {
EhIndexToArray(indices[i], array.data()+(i*sizeof(eh_index)));
}
std::vector<unsigned char> ret(minLen);
CompressArray(array.data(), lenIndices,
ret.data(), minLen, cBitLen+1, bytePad);
return ret;
}
template<size_t WIDTH>
StepRow<WIDTH>::StepRow(const unsigned char* hashIn, size_t hInLen,
size_t hLen, size_t cBitLen)
{
assert(hLen <= WIDTH);
ExpandArray(hashIn, hInLen, hash, hLen, cBitLen);
}
template<size_t WIDTH> template<size_t W>
StepRow<WIDTH>::StepRow(const StepRow<W>& a)
{
BOOST_STATIC_ASSERT(W <= WIDTH);
std::copy(a.hash, a.hash+W, hash);
}
template<size_t WIDTH>
FullStepRow<WIDTH>::FullStepRow(const unsigned char* hashIn, size_t hInLen,
size_t hLen, size_t cBitLen, eh_index i) :
StepRow<WIDTH> {hashIn, hInLen, hLen, cBitLen}
{
EhIndexToArray(i, hash+hLen);
}
template<size_t WIDTH> template<size_t W>
FullStepRow<WIDTH>::FullStepRow(const FullStepRow<W>& a, const FullStepRow<W>& b, size_t len, size_t lenIndices, int trim) :
StepRow<WIDTH> {a}
{
assert(len+lenIndices <= W);
assert(len-trim+(2*lenIndices) <= WIDTH);
for (int i = trim; i < len; i++)
hash[i-trim] = a.hash[i] ^ b.hash[i];
if (a.IndicesBefore(b, len, lenIndices)) {
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-trim);
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-trim+lenIndices);
} else {
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-trim);
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-trim+lenIndices);
}
}
template<size_t WIDTH>
FullStepRow<WIDTH>& FullStepRow<WIDTH>::operator=(const FullStepRow<WIDTH>& a)
{
std::copy(a.hash, a.hash+WIDTH, hash);
return *this;
}
template<size_t WIDTH>
bool StepRow<WIDTH>::IsZero(size_t len)
{
// This doesn't need to be constant time.
for (int i = 0; i < len; i++) {
if (hash[i] != 0)
return false;
}
return true;
}
template<size_t WIDTH>
std::vector<unsigned char> FullStepRow<WIDTH>::GetIndices(size_t len, size_t lenIndices,
size_t cBitLen) const
{
assert(((cBitLen+1)+7)/8 <= sizeof(eh_index));
size_t minLen { (cBitLen+1)*lenIndices/(8*sizeof(eh_index)) };
size_t bytePad { sizeof(eh_index) - ((cBitLen+1)+7)/8 };
std::vector<unsigned char> ret(minLen);
CompressArray(hash+len, lenIndices, ret.data(), minLen, cBitLen+1, bytePad);
return ret;
}
template<size_t WIDTH>
bool HasCollision(StepRow<WIDTH>& a, StepRow<WIDTH>& b, int l)
{
// This doesn't need to be constant time.
for (int j = 0; j < l; j++) {
if (a.hash[j] != b.hash[j])
return false;
}
return true;
}
template<size_t WIDTH>
TruncatedStepRow<WIDTH>::TruncatedStepRow(const unsigned char* hashIn, size_t hInLen,
size_t hLen, size_t cBitLen,
eh_index i, unsigned int ilen) :
StepRow<WIDTH> {hashIn, hInLen, hLen, cBitLen}
{
hash[hLen] = TruncateIndex(i, ilen);
}
template<size_t WIDTH> template<size_t W>
TruncatedStepRow<WIDTH>::TruncatedStepRow(const TruncatedStepRow<W>& a, const TruncatedStepRow<W>& b, size_t len, size_t lenIndices, int trim) :
StepRow<WIDTH> {a}
{
assert(len+lenIndices <= W);
assert(len-trim+(2*lenIndices) <= WIDTH);
for (int i = trim; i < len; i++)
hash[i-trim] = a.hash[i] ^ b.hash[i];
if (a.IndicesBefore(b, len, lenIndices)) {
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-trim);
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-trim+lenIndices);
} else {
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-trim);
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-trim+lenIndices);
}
}
template<size_t WIDTH>
TruncatedStepRow<WIDTH>& TruncatedStepRow<WIDTH>::operator=(const TruncatedStepRow<WIDTH>& a)
{
std::copy(a.hash, a.hash+WIDTH, hash);
return *this;
}
template<size_t WIDTH>
std::shared_ptr<eh_trunc> TruncatedStepRow<WIDTH>::GetTruncatedIndices(size_t len, size_t lenIndices) const
{
std::shared_ptr<eh_trunc> p (new eh_trunc[lenIndices], std::default_delete<eh_trunc[]>());
std::copy(hash+len, hash+len+lenIndices, p.get());
return p;
}
#ifdef ENABLE_MINING
template<unsigned int N, unsigned int K>
bool Equihash<N,K>::BasicSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled)
{
eh_index init_size { 1 << (CollisionBitLength + 1) };
// 1) Generate first list
LogPrint("pow", "Generating first list\n");
size_t hashLen = HashLength;
size_t lenIndices = sizeof(eh_index);
std::vector<FullStepRow<FullWidth>> X;
X.reserve(init_size);
unsigned char tmpHash[HashOutput];
for (eh_index g = 0; X.size() < init_size; g++) {
GenerateHash(base_state, g, tmpHash, HashOutput);
for (eh_index i = 0; i < IndicesPerHashOutput && X.size() < init_size; i++) {
X.emplace_back(tmpHash+(i*N/8), N/8, HashLength,
CollisionBitLength, (g*IndicesPerHashOutput)+i);
}
if (cancelled(ListGeneration)) throw solver_cancelled;
}
// 3) Repeat step 2 until 2n/(k+1) bits remain
for (int r = 1; r < K && X.size() > 0; r++) {
LogPrint("pow", "Round %d:\n", r);
// 2a) Sort the list
LogPrint("pow", "- Sorting list\n");
std::sort(X.begin(), X.end(), CompareSR(CollisionByteLength));
if (cancelled(ListSorting)) throw solver_cancelled;
LogPrint("pow", "- Finding collisions\n");
int i = 0;
int posFree = 0;
std::vector<FullStepRow<FullWidth>> Xc;
while (i < X.size() - 1) {
// 2b) Find next set of unordered pairs with collisions on the next n/(k+1) bits
int j = 1;
while (i+j < X.size() &&
HasCollision(X[i], X[i+j], CollisionByteLength)) {
j++;
}
// 2c) Calculate tuples (X_i ^ X_j, (i, j))
for (int l = 0; l < j - 1; l++) {
for (int m = l + 1; m < j; m++) {
if (DistinctIndices(X[i+l], X[i+m], hashLen, lenIndices)) {
Xc.emplace_back(X[i+l], X[i+m], hashLen, lenIndices, CollisionByteLength);
}
}
}
// 2d) Store tuples on the table in-place if possible
while (posFree < i+j && Xc.size() > 0) {
X[posFree++] = Xc.back();
Xc.pop_back();
}
i += j;
if (cancelled(ListColliding)) throw solver_cancelled;
}
// 2e) Handle edge case where final table entry has no collision
while (posFree < X.size() && Xc.size() > 0) {
X[posFree++] = Xc.back();
Xc.pop_back();
}
if (Xc.size() > 0) {
// 2f) Add overflow to end of table
X.insert(X.end(), Xc.begin(), Xc.end());
} else if (posFree < X.size()) {
// 2g) Remove empty space at the end
X.erase(X.begin()+posFree, X.end());
X.shrink_to_fit();
}
hashLen -= CollisionByteLength;
lenIndices *= 2;
if (cancelled(RoundEnd)) throw solver_cancelled;
}
// k+1) Find a collision on last 2n(k+1) bits
LogPrint("pow", "Final round:\n");
if (X.size() > 1) {
LogPrint("pow", "- Sorting list\n");
std::sort(X.begin(), X.end(), CompareSR(hashLen));
if (cancelled(FinalSorting)) throw solver_cancelled;
LogPrint("pow", "- Finding collisions\n");
int i = 0;
while (i < X.size() - 1) {
int j = 1;
while (i+j < X.size() &&
HasCollision(X[i], X[i+j], hashLen)) {
j++;
}
for (int l = 0; l < j - 1; l++) {
for (int m = l + 1; m < j; m++) {
FullStepRow<FinalFullWidth> res(X[i+l], X[i+m], hashLen, lenIndices, 0);
if (DistinctIndices(X[i+l], X[i+m], hashLen, lenIndices)) {
auto soln = res.GetIndices(hashLen, 2*lenIndices, CollisionBitLength);
assert(soln.size() == equihash_solution_size(N, K));
if (validBlock(soln)) {
return true;
}
}
}
}
i += j;
if (cancelled(FinalColliding)) throw solver_cancelled;
}
} else
LogPrint("pow", "- List is empty\n");
return false;
}
template<size_t WIDTH>
void CollideBranches(std::vector<FullStepRow<WIDTH>>& X, const size_t hlen, const size_t lenIndices, const unsigned int clen, const unsigned int ilen, const eh_trunc lt, const eh_trunc rt)
{
int i = 0;
int posFree = 0;
std::vector<FullStepRow<WIDTH>> Xc;
while (i < X.size() - 1) {
// 2b) Find next set of unordered pairs with collisions on the next n/(k+1) bits
int j = 1;
while (i+j < X.size() &&
HasCollision(X[i], X[i+j], clen)) {
j++;
}
// 2c) Calculate tuples (X_i ^ X_j, (i, j))
for (int l = 0; l < j - 1; l++) {
for (int m = l + 1; m < j; m++) {
if (DistinctIndices(X[i+l], X[i+m], hlen, lenIndices)) {
if (IsValidBranch(X[i+l], hlen, ilen, lt) && IsValidBranch(X[i+m], hlen, ilen, rt)) {
Xc.emplace_back(X[i+l], X[i+m], hlen, lenIndices, clen);
} else if (IsValidBranch(X[i+m], hlen, ilen, lt) && IsValidBranch(X[i+l], hlen, ilen, rt)) {
Xc.emplace_back(X[i+m], X[i+l], hlen, lenIndices, clen);
}
}
}
}
// 2d) Store tuples on the table in-place if possible
while (posFree < i+j && Xc.size() > 0) {
X[posFree++] = Xc.back();
Xc.pop_back();
}
i += j;
}
// 2e) Handle edge case where final table entry has no collision
while (posFree < X.size() && Xc.size() > 0) {
X[posFree++] = Xc.back();
Xc.pop_back();
}
if (Xc.size() > 0) {
// 2f) Add overflow to end of table
X.insert(X.end(), Xc.begin(), Xc.end());
} else if (posFree < X.size()) {
// 2g) Remove empty space at the end
X.erase(X.begin()+posFree, X.end());
X.shrink_to_fit();
}
}
template<unsigned int N, unsigned int K>
bool Equihash<N,K>::OptimisedSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled)
{
eh_index init_size { 1 << (CollisionBitLength + 1) };
eh_index recreate_size { UntruncateIndex(1, 0, CollisionBitLength + 1) };
// First run the algorithm with truncated indices
const eh_index soln_size { 1 << K };
std::vector<std::shared_ptr<eh_trunc>> partialSolns;
int invalidCount = 0;
{
// 1) Generate first list
LogPrint("pow", "Generating first list\n");
size_t hashLen = HashLength;
size_t lenIndices = sizeof(eh_trunc);
std::vector<TruncatedStepRow<TruncatedWidth>> Xt;
Xt.reserve(init_size);
unsigned char tmpHash[HashOutput];
for (eh_index g = 0; Xt.size() < init_size; g++) {
GenerateHash(base_state, g, tmpHash, HashOutput);
for (eh_index i = 0; i < IndicesPerHashOutput && Xt.size() < init_size; i++) {
Xt.emplace_back(tmpHash+(i*N/8), N/8, HashLength, CollisionBitLength,
(g*IndicesPerHashOutput)+i, CollisionBitLength + 1);
}
if (cancelled(ListGeneration)) throw solver_cancelled;
}
// 3) Repeat step 2 until 2n/(k+1) bits remain
for (int r = 1; r < K && Xt.size() > 0; r++) {
LogPrint("pow", "Round %d:\n", r);
// 2a) Sort the list
LogPrint("pow", "- Sorting list\n");
std::sort(Xt.begin(), Xt.end(), CompareSR(CollisionByteLength));
if (cancelled(ListSorting)) throw solver_cancelled;
LogPrint("pow", "- Finding collisions\n");
int i = 0;
int posFree = 0;
std::vector<TruncatedStepRow<TruncatedWidth>> Xc;
while (i < Xt.size() - 1) {
// 2b) Find next set of unordered pairs with collisions on the next n/(k+1) bits
int j = 1;
while (i+j < Xt.size() &&
HasCollision(Xt[i], Xt[i+j], CollisionByteLength)) {
j++;
}
// 2c) Calculate tuples (X_i ^ X_j, (i, j))
bool checking_for_zero = (i == 0 && Xt[0].IsZero(hashLen));
for (int l = 0; l < j - 1; l++) {
for (int m = l + 1; m < j; m++) {
// We truncated, so don't check for distinct indices here
TruncatedStepRow<TruncatedWidth> Xi {Xt[i+l], Xt[i+m],
hashLen, lenIndices,
CollisionByteLength};
if (!(Xi.IsZero(hashLen-CollisionByteLength) &&
IsProbablyDuplicate<soln_size>(Xi.GetTruncatedIndices(hashLen-CollisionByteLength, 2*lenIndices),
2*lenIndices))) {
Xc.emplace_back(Xi);
}
}
}
// 2d) Store tuples on the table in-place if possible
while (posFree < i+j && Xc.size() > 0) {
Xt[posFree++] = Xc.back();
Xc.pop_back();
}
i += j;
if (cancelled(ListColliding)) throw solver_cancelled;
}
// 2e) Handle edge case where final table entry has no collision
while (posFree < Xt.size() && Xc.size() > 0) {
Xt[posFree++] = Xc.back();
Xc.pop_back();
}
if (Xc.size() > 0) {
// 2f) Add overflow to end of table
Xt.insert(Xt.end(), Xc.begin(), Xc.end());
} else if (posFree < Xt.size()) {
// 2g) Remove empty space at the end
Xt.erase(Xt.begin()+posFree, Xt.end());
Xt.shrink_to_fit();
}
hashLen -= CollisionByteLength;
lenIndices *= 2;
if (cancelled(RoundEnd)) throw solver_cancelled;
}
// k+1) Find a collision on last 2n(k+1) bits
LogPrint("pow", "Final round:\n");
if (Xt.size() > 1) {
LogPrint("pow", "- Sorting list\n");
std::sort(Xt.begin(), Xt.end(), CompareSR(hashLen));
if (cancelled(FinalSorting)) throw solver_cancelled;
LogPrint("pow", "- Finding collisions\n");
int i = 0;
while (i < Xt.size() - 1) {
int j = 1;
while (i+j < Xt.size() &&
HasCollision(Xt[i], Xt[i+j], hashLen)) {
j++;
}
for (int l = 0; l < j - 1; l++) {
for (int m = l + 1; m < j; m++) {
TruncatedStepRow<FinalTruncatedWidth> res(Xt[i+l], Xt[i+m],
hashLen, lenIndices, 0);
auto soln = res.GetTruncatedIndices(hashLen, 2*lenIndices);
if (!IsProbablyDuplicate<soln_size>(soln, 2*lenIndices)) {
partialSolns.push_back(soln);
}
}
}
i += j;
if (cancelled(FinalColliding)) throw solver_cancelled;
}
} else
LogPrint("pow", "- List is empty\n");
} // Ensure Xt goes out of scope and is destroyed
LogPrint("pow", "Found %d partial solutions\n", partialSolns.size());
// Now for each solution run the algorithm again to recreate the indices
LogPrint("pow", "Culling solutions\n");
for (std::shared_ptr<eh_trunc> partialSoln : partialSolns) {
std::set<std::vector<unsigned char>> solns;
size_t hashLen;
size_t lenIndices;
unsigned char tmpHash[HashOutput];
std::vector<boost::optional<std::vector<FullStepRow<FinalFullWidth>>>> X;
X.reserve(K+1);
// 3) Repeat steps 1 and 2 for each partial index
for (eh_index i = 0; i < soln_size; i++) {
// 1) Generate first list of possibilities
std::vector<FullStepRow<FinalFullWidth>> icv;
icv.reserve(recreate_size);
for (eh_index j = 0; j < recreate_size; j++) {
eh_index newIndex { UntruncateIndex(partialSoln.get()[i], j, CollisionBitLength + 1) };
if (j == 0 || newIndex % IndicesPerHashOutput == 0) {
GenerateHash(base_state, newIndex/IndicesPerHashOutput,
tmpHash, HashOutput);
}
icv.emplace_back(tmpHash+((newIndex % IndicesPerHashOutput) * N/8),
N/8, HashLength, CollisionBitLength, newIndex);
if (cancelled(PartialGeneration)) throw solver_cancelled;
}
boost::optional<std::vector<FullStepRow<FinalFullWidth>>> ic = icv;
// 2a) For each pair of lists:
hashLen = HashLength;
lenIndices = sizeof(eh_index);
size_t rti = i;
for (size_t r = 0; r <= K; r++) {
// 2b) Until we are at the top of a subtree:
if (r < X.size()) {
if (X[r]) {
// 2c) Merge the lists
ic->reserve(ic->size() + X[r]->size());
ic->insert(ic->end(), X[r]->begin(), X[r]->end());
std::sort(ic->begin(), ic->end(), CompareSR(hashLen));
if (cancelled(PartialSorting)) throw solver_cancelled;
size_t lti = rti-(1<<r);
CollideBranches(*ic, hashLen, lenIndices,
CollisionByteLength,
CollisionBitLength + 1,
partialSoln.get()[lti], partialSoln.get()[rti]);
// 2d) Check if this has become an invalid solution
if (ic->size() == 0)
goto invalidsolution;
X[r] = boost::none;
hashLen -= CollisionByteLength;
lenIndices *= 2;
rti = lti;
} else {
X[r] = *ic;
break;
}
} else {
X.push_back(ic);
break;
}
if (cancelled(PartialSubtreeEnd)) throw solver_cancelled;
}
if (cancelled(PartialIndexEnd)) throw solver_cancelled;
}
// We are at the top of the tree
assert(X.size() == K+1);
for (FullStepRow<FinalFullWidth> row : *X[K]) {
auto soln = row.GetIndices(hashLen, lenIndices, CollisionBitLength);
assert(soln.size() == equihash_solution_size(N, K));
solns.insert(soln);
}
for (auto soln : solns) {
if (validBlock(soln))
return true;
}
if (cancelled(PartialEnd)) throw solver_cancelled;
continue;
invalidsolution:
invalidCount++;
}
LogPrint("pow", "- Number of invalid solutions found: %d\n", invalidCount);
return false;
}
#endif // ENABLE_MINING
template<unsigned int N, unsigned int K>
bool Equihash<N,K>::IsValidSolution(const eh_HashState& base_state, std::vector<unsigned char> soln)
{
if (soln.size() != SolutionWidth) {
LogPrint("pow", "Invalid solution length: %d (expected %d)\n",
soln.size(), SolutionWidth);
return false;
}
std::vector<FullStepRow<FinalFullWidth>> X;
X.reserve(1 << K);
unsigned char tmpHash[HashOutput];
for (eh_index i : GetIndicesFromMinimal(soln, CollisionBitLength)) {
GenerateHash(base_state, i/IndicesPerHashOutput, tmpHash, HashOutput);
X.emplace_back(tmpHash+((i % IndicesPerHashOutput) * N/8),
N/8, HashLength, CollisionBitLength, i);
}
size_t hashLen = HashLength;
size_t lenIndices = sizeof(eh_index);
while (X.size() > 1) {
std::vector<FullStepRow<FinalFullWidth>> Xc;
for (int i = 0; i < X.size(); i += 2) {
if (!HasCollision(X[i], X[i+1], CollisionByteLength)) {
LogPrint("pow", "Invalid solution: invalid collision length between StepRows\n");
LogPrint("pow", "X[i] = %s\n", X[i].GetHex(hashLen));
LogPrint("pow", "X[i+1] = %s\n", X[i+1].GetHex(hashLen));
return false;
}
if (X[i+1].IndicesBefore(X[i], hashLen, lenIndices)) {
LogPrint("pow", "Invalid solution: Index tree incorrectly ordered\n");
return false;
}
if (!DistinctIndices(X[i], X[i+1], hashLen, lenIndices)) {
LogPrint("pow", "Invalid solution: duplicate indices\n");
return false;
}
Xc.emplace_back(X[i], X[i+1], hashLen, lenIndices, CollisionByteLength);
}
X = Xc;
hashLen -= CollisionByteLength;
lenIndices *= 2;
}
assert(X.size() == 1);
return X[0].IsZero(hashLen);
}
// Explicit instantiations for Equihash<96,3>
template int Equihash<96,3>::InitialiseState(eh_HashState& base_state);
#ifdef ENABLE_MINING
template bool Equihash<96,3>::BasicSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
template bool Equihash<96,3>::OptimisedSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
#endif
template bool Equihash<96,3>::IsValidSolution(const eh_HashState& base_state, std::vector<unsigned char> soln);
// Explicit instantiations for Equihash<200,9>
template int Equihash<200,9>::InitialiseState(eh_HashState& base_state);
#ifdef ENABLE_MINING
template bool Equihash<200,9>::BasicSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
template bool Equihash<200,9>::OptimisedSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
#endif
template bool Equihash<200,9>::IsValidSolution(const eh_HashState& base_state, std::vector<unsigned char> soln);
// Explicit instantiations for Equihash<96,5>
template int Equihash<96,5>::InitialiseState(eh_HashState& base_state);
#ifdef ENABLE_MINING
template bool Equihash<96,5>::BasicSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
template bool Equihash<96,5>::OptimisedSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
#endif
template bool Equihash<96,5>::IsValidSolution(const eh_HashState& base_state, std::vector<unsigned char> soln);
// Explicit instantiations for Equihash<48,5>
template int Equihash<48,5>::InitialiseState(eh_HashState& base_state);
#ifdef ENABLE_MINING
template bool Equihash<48,5>::BasicSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
template bool Equihash<48,5>::OptimisedSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
#endif
template bool Equihash<48,5>::IsValidSolution(const eh_HashState& base_state, std::vector<unsigned char> soln);
// Explicit instantiations for Equihash<144,5>
template int Equihash<144,5>::InitialiseState(eh_HashState& base_state);
#ifdef ENABLE_MINING
template bool Equihash<144,5>::BasicSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
template bool Equihash<144,5>::OptimisedSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
#endif
template bool Equihash<144,5>::IsValidSolution(const eh_HashState& base_state, std::vector<unsigned char> soln);
// Explicit instantiations for Equihash<192,7>
template int Equihash<192,7>::InitialiseState(eh_HashState& base_state);
#ifdef ENABLE_MINING
template bool Equihash<192, 7>::BasicSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
template bool Equihash<192, 7>::OptimisedSolve(const eh_HashState& base_state,
const std::function<bool(std::vector<unsigned char>)> validBlock,
const std::function<bool(EhSolverCancelCheck)> cancelled);
#endif
template bool Equihash<192, 7>::IsValidSolution(const eh_HashState& base_state, std::vector<unsigned char> soln);
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