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privacy improvement: one derivation hint per output (not per receiver as before)

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sowle 2024-03-13 21:29:09 +01:00
parent b99bdb68df
commit 41386a91c8
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GPG key ID: C07A24B2D89D49FC
1 changed files with 58 additions and 28 deletions
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86
src/currency_core/currency_format_utils.cpp
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@ -261,6 +261,30 @@ namespace currency
return diff;
}
//------------------------------------------------------------------
bool add_random_derivation_hints_and_put_them_to_tx(const std::set<uint16_t>& existing_derivation_hints, std::set<uint16_t>& new_derivation_hints, transaction& tx)
{
if (existing_derivation_hints.size() > tx.vout.size())
return false;
size_t hints_to_be_added = tx.vout.size() - existing_derivation_hints.size();
size_t attempts_cnt = 0, attempts_max = 4096;
while(new_derivation_hints.size() < hints_to_be_added && ++attempts_cnt < attempts_max)
{
uint16_t hint = crypto::rand<uint16_t>();
if (existing_derivation_hints.count(hint) == 0)
new_derivation_hints.insert(hint);
}
if (attempts_cnt == attempts_max)
return false;
for(auto& el : new_derivation_hints) // iterating in sorted sequence
tx.extra.push_back(make_tx_derivation_hint_from_uint16(el));
return true;
}
//---------------------------------------------------------------
bool generate_tx_balance_proof(const transaction &tx, const crypto::hash& tx_id, const tx_generation_context& ogc, uint64_t block_reward_for_miner_tx, currency::zc_balance_proof& proof)
{
CHECK_AND_ASSERT_MES(tx.version > TRANSACTION_VERSION_PRE_HF4, false, "unsupported tx.version: " << tx.version);
@ -488,12 +512,12 @@ namespace currency
// fill outputs
tx_gen_context.resize(zc_ins_count, destinations.size()); // auxiliary data for each output
uint64_t output_index = 0;
std::set<uint16_t> deriv_cache;
std::set<uint16_t> derivation_hints;
for (auto& d : destinations)
{
finalized_tx result = AUTO_VAL_INIT(result);
uint8_t tx_outs_attr = 0;
r = construct_tx_out(d, tx_gen_context.tx_key.sec, output_index, tx, deriv_cache, account_keys(),
r = construct_tx_out(d, tx_gen_context.tx_key.sec, output_index, tx, derivation_hints, account_keys(),
tx_gen_context.asset_id_blinding_masks[output_index], tx_gen_context.amount_blinding_masks[output_index],
tx_gen_context.blinded_asset_ids[output_index], tx_gen_context.amount_commitments[output_index], result, tx_outs_attr);
CHECK_AND_ASSERT_MES(r, false, "construct_tx_out failed, output #" << output_index << ", amount: " << print_money_brief(d.amount));
@ -504,6 +528,7 @@ namespace currency
tx_gen_context.amount_commitments_sum += tx_gen_context.amount_commitments[output_index];
++output_index;
}
CHECK_AND_ASSERT_MES(add_random_derivation_hints_and_put_them_to_tx(std::set<uint16_t>(), derivation_hints, tx), false, "add_random_derivation_hints_and_put_them_to_tx failed");
if (tx.attachment.size())
add_attachments_info_to_extra(tx.extra, tx.attachment);
@ -1116,14 +1141,13 @@ namespace currency
return dh;
}
//---------------------------------------------------------------
// bool get_uint16_from_tx_derivation_hint(const tx_derivation_hint& dh, uint16_t& hint)
// {
// tx_derivation_hint dh;
// if (dh.msg.size() != sizeof(hint))
// return false;
// hint = *((uint16_t*)dh.msg.data());
// return true;
// }
bool get_uint16_from_tx_derivation_hint(const tx_derivation_hint& dh, uint16_t& hint)
{
if (dh.msg.size() != sizeof(hint))
return false;
hint = *((uint16_t*)dh.msg.data());
return true;
}
//---------------------------------------------------------------
std::string generate_origin_for_htlc(const txout_htlc& htlc, const account_keys& acc_keys)
{
@ -1250,11 +1274,7 @@ namespace currency
out.mix_attr = tx_outs_attr;
uint16_t hint = get_derivation_hint(reinterpret_cast<crypto::key_derivation&>(derivation));
if (deriv_cache.count(hint) == 0)
{
tx.extra.push_back(make_tx_derivation_hint_from_uint16(hint));
deriv_cache.insert(hint);
}
deriv_cache.insert(hint); // won't be inserted if such hint already exists
}
tx.vout.push_back(out);
@ -1282,11 +1302,7 @@ namespace currency
CHECK_AND_ASSERT_MES(r, false, "failed to derive_public_key_from_target_address");
uint16_t hint = get_derivation_hint(derivation);
if (deriv_cache.count(hint) == 0)
{
tx.extra.push_back(make_tx_derivation_hint_from_uint16(hint));
deriv_cache.insert(hint);
}
deriv_cache.insert(hint); // won't be inserted if such hint already exists
}
target_keys.push_back(out_eph_public_key);
}
@ -1311,11 +1327,7 @@ namespace currency
htlc.pkey_refund = out_eph_public_key;
//add derivation hint for refund address
uint16_t hint = get_derivation_hint(derivation);
if (deriv_cache.count(hint) == 0)
{
tx.extra.push_back(make_tx_derivation_hint_from_uint16(hint));
deriv_cache.insert(hint);
}
deriv_cache.insert(hint); // won't be inserted if such hint already exists
if (htlc_dest.htlc_hash == null_hash)
@ -1905,7 +1917,22 @@ namespace currency
}
return n;
}
//---------------------------------------------------------------
bool copy_all_derivation_hints_from_tx_to_container(transaction& tx, std::set<uint16_t>& derivation_hints)
{
for(auto it = tx.extra.begin(); it != tx.extra.end(); ++it)
{
if (it->type() == typeid(tx_derivation_hint))
{
uint16_t hint = 0;
if (!get_uint16_from_tx_derivation_hint(boost::get<tx_derivation_hint>(*it), hint))
return false;
if (!derivation_hints.insert(hint).second)
return false; // maybe we need to skip this?
}
}
return true;
}
//---------------------------------------------------------------
bool construct_tx(const account_keys& sender_account_keys,
const std::vector<tx_source_entry>& sources,
@ -2575,14 +2602,15 @@ namespace currency
uint64_t native_coins_output_sum = 0;
size_t output_index = tx.vout.size(); // in case of append mode we need to start output indexing from the last one + 1
uint64_t range_proof_start_index = 0;
std::set<uint16_t> deriv_cache;
std::set<uint16_t> existing_derivation_hints, new_derivation_hints;
CHECK_AND_ASSERT_MES(copy_all_derivation_hints_from_tx_to_container(tx, existing_derivation_hints), false, "move_all_derivation_hints_from_tx_to_container failed");
for(size_t destination_index = 0; destination_index < shuffled_dsts.size(); ++destination_index, ++output_index)
{
tx_destination_entry& dst_entr = shuffled_dsts[destination_index];
if (!(flags & TX_FLAG_SIGNATURE_MODE_SEPARATE) && all_inputs_are_obviously_native_coins && gen_context.ao_asset_id == currency::null_pkey)
dst_entr.flags |= tx_destination_entry_flags::tdef_explicit_native_asset_id; // all inputs are obviously native coins -- all outputs must have explicit asset ids (unless there's an asset emission)
r = construct_tx_out(dst_entr, gen_context.tx_key.sec, output_index, tx, deriv_cache, sender_account_keys,
r = construct_tx_out(dst_entr, gen_context.tx_key.sec, output_index, tx, new_derivation_hints, sender_account_keys,
gen_context.asset_id_blinding_masks[output_index], gen_context.amount_blinding_masks[output_index],
gen_context.blinded_asset_ids[output_index], gen_context.amount_commitments[output_index], result, tx_outs_attr);
CHECK_AND_ASSERT_MES(r, false, "Failed to construct tx out");
@ -2595,6 +2623,8 @@ namespace currency
native_coins_output_sum += dst_entr.amount;
}
CHECK_AND_ASSERT_MES(add_random_derivation_hints_and_put_them_to_tx(existing_derivation_hints, new_derivation_hints, tx), false, "add_random_derivation_hints_and_put_them_to_tx failed");
//process offers and put there offers derived keys
uint64_t att_count = 0;
for (auto& o : tx.attachment)