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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 <optional> | |
#ifdef ENABLE_MINING | |
void eh_HashState::Update(const unsigned char *input, size_t inputLen) | |
{ | |
blake2b_update(inner.get(), input, inputLen); | |
} | |
void eh_HashState::Finalize(unsigned char *hash, size_t hLen) | |
{ | |
blake2b_finalize(inner.get(), hash, hLen); | |
} | |
#endif | |
// Used in TestEquihashValidator. | |
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; | |
} | |
} | |
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; | |
} | |
} | |
} | |
// Big-endian so that lexicographic array comparison is equivalent to integer | |
// comparison | |
void EhIndexToArray(const eh_index i, unsigned char* array) | |
{ | |
static_assert(sizeof(eh_index) == 4); | |
eh_index bei = htobe32(i); | |
memcpy(array, &bei, sizeof(eh_index)); | |
} | |
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; | |
} | |
#ifdef ENABLE_MINING | |
#include <algorithm> | |
#include <iostream> | |
#include <stdexcept> | |
static EhSolverCancelledException solver_cancelled; | |
template<unsigned int N, unsigned int K> | |
void Equihash<N,K>::InitialiseState(eh_HashState& base_state) | |
{ | |
uint32_t le_N = htole32(N); | |
uint32_t le_K = htole32(K); | |
unsigned char personalization[BLAKE2bPersonalBytes] = {}; | |
memcpy(personalization, "ZcashPoW", 8); | |
memcpy(personalization+8, &le_N, 4); | |
memcpy(personalization+12, &le_K, 4); | |
base_state = eh_HashState((512/N)*N/8, personalization); | |
} | |
void GenerateHash(const eh_HashState& base_state, eh_index g, | |
unsigned char* hash, size_t hLen) | |
{ | |
eh_HashState state(base_state); | |
eh_index lei = htole32(g); | |
state.Update((const unsigned char*) &lei, sizeof(eh_index)); | |
state.Finalize(hash, hLen); | |
} | |
// Big-endian so that lexicographic array comparison is equivalent to integer | |
// comparison | |
eh_index ArrayToEhIndex(const unsigned char* array) | |
{ | |
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 | |
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; | |
} | |
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) | |
{ | |
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 lenTrim) : | |
StepRow<WIDTH> {a} | |
{ | |
assert(len+lenIndices <= W); | |
assert(len-lenTrim+(2*lenIndices) <= WIDTH); | |
for (int i = lenTrim; i < len; i++) | |
hash[i-lenTrim] = a.hash[i] ^ b.hash[i]; | |
if (a.IndicesBefore(b, len, lenIndices)) { | |
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-lenTrim); | |
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-lenTrim+lenIndices); | |
} else { | |
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-lenTrim); | |
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-lenTrim+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 lenTrim) : | |
StepRow<WIDTH> {a} | |
{ | |
assert(len+lenIndices <= W); | |
assert(len-lenTrim+(2*lenIndices) <= WIDTH); | |
for (int i = lenTrim; i < len; i++) | |
hash[i-lenTrim] = a.hash[i] ^ b.hash[i]; | |
if (a.IndicesBefore(b, len, lenIndices)) { | |
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-lenTrim); | |
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-lenTrim+lenIndices); | |
} else { | |
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-lenTrim); | |
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-lenTrim+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; | |
} | |
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<std::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; | |
} | |
std::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] = std::nullopt; | |
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; | |
} | |
// Explicit instantiations for Equihash<96,3> | |
template void Equihash<96,3>::InitialiseState(eh_HashState& base_state); | |
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); | |
// Explicit instantiations for Equihash<200,9> | |
template void Equihash<200,9>::InitialiseState(eh_HashState& base_state); | |
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); | |
// Explicit instantiations for Equihash<96,5> | |
template void Equihash<96,5>::InitialiseState(eh_HashState& base_state); | |
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); | |
// Explicit instantiations for Equihash<48,5> | |
template void Equihash<48,5>::InitialiseState(eh_HashState& base_state); | |
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); | |
// Explicit instantiations for Equihash<144,5> | |
template void Equihash<144,5>::InitialiseState(eh_HashState& base_state); | |
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); | |
// Explicit instantiations for Equihash<192,7> | |
template void Equihash<192,7>::InitialiseState(eh_HashState& base_state); | |
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 // ENABLE_MINING |