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refactor: Generalize derivation target calculation

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This commit is contained in:
David Gumberg 2025-05-05 20:23:28 -07:00
parent 951863d022
commit ae5485fa0d
1 changed files with 11 additions and 7 deletions
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18
src/wallet/wallet.cpp
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@ -579,16 +579,20 @@ void CWallet::UpgradeDescriptorCache()
* derivation parameters (should take at least 100ms) and encrypt the master key. */
static bool EncryptMasterKey(const SecureString& wallet_passphrase, const CKeyingMaterial& plain_master_key, CMasterKey& master_key)
{
constexpr MillisecondsDouble target{100};
auto start{SteadyClock::now()};
constexpr MillisecondsDouble target_time{100};
CCrypter crypter;
crypter.SetKeyFromPassphrase(wallet_passphrase, master_key.vchSalt, master_key.nDeriveIterations, master_key.nDerivationMethod);
master_key.nDeriveIterations = static_cast<unsigned int>(master_key.nDeriveIterations * target / (SteadyClock::now() - start));
// Get the weighted average of iterations we can do in 100ms over 2 runs.
for (int i = 0; i < 2; i++){
auto start_time{SteadyClock::now()};
crypter.SetKeyFromPassphrase(wallet_passphrase, master_key.vchSalt, master_key.nDeriveIterations, master_key.nDerivationMethod);
auto elapsed_time{SteadyClock::now() - start_time};
start = SteadyClock::now();
crypter.SetKeyFromPassphrase(wallet_passphrase, master_key.vchSalt, master_key.nDeriveIterations, master_key.nDerivationMethod);
master_key.nDeriveIterations = (master_key.nDeriveIterations + static_cast<unsigned int>(master_key.nDeriveIterations * target / (SteadyClock::now() - start))) / 2;
// target_iterations : elapsed_iterations :: target_time : elapsed_time
unsigned int target_iterations = master_key.nDeriveIterations * target_time / elapsed_time;
// Get the weighted average with previous runs.
master_key.nDeriveIterations = (i * master_key.nDeriveIterations + target_iterations) / (i + 1);
}
if (master_key.nDeriveIterations < CMasterKey::DEFAULT_DERIVE_ITERATIONS) {
master_key.nDeriveIterations = CMasterKey::DEFAULT_DERIVE_ITERATIONS;