static void mul(const uint8_t* a, const uint8_t* b, uint8_t* res) {
uint64_t a0, b0;
uint64_t hi, lo;
a0 = SWAP64LE(((uint64_t*) a)[0]);
b0 = SWAP64LE(((uint64_t*) b)[0]);
lo = mul128(a0, b0, &hi);
((uint64_t*) res)[0] = SWAP64LE(hi);
((uint64_t*) res)[1] = SWAP64LE(lo);
}
bool tx_extra_message::decrypt(size_t index, const Crypto::PublicKey &txkey, const Crypto::SecretKey *recepient_secret_key, std::string &message) const {
size_t mlen = data.size();
if (mlen < TX_EXTRA_MESSAGE_CHECKSUM_SIZE) {
return false;
}
const char *buf;
std::unique_ptr<char[]> ptr;
if (recepient_secret_key != nullptr) {
ptr.reset(new char[mlen]);
assert(ptr);
message_key_data key_data;
if (!generate_key_derivation(txkey, *recepient_secret_key, key_data.derivation)) {
return false;
}
key_data.magic1 = 0x80;
key_data.magic2 = 0;
Hash h = cn_fast_hash(&key_data, sizeof(message_key_data));
uint64_t nonce = SWAP64LE(index);
chacha(10, data.data(), mlen, reinterpret_cast<uint8_t *>(&h), reinterpret_cast<uint8_t *>(&nonce), ptr.get());
buf = ptr.get();
} else {
buf = data.data();
}
mlen -= TX_EXTRA_MESSAGE_CHECKSUM_SIZE;
for (size_t i = 0; i < TX_EXTRA_MESSAGE_CHECKSUM_SIZE; i++) {
if (buf[mlen + i] != 0) {
return false;
}
}
message.assign(buf, mlen);
return true;
}
static void sum_half_blocks(uint8_t* a, const uint8_t* b) {
uint64_t a0, a1, b0, b1;
a0 = SWAP64LE(((uint64_t*) a)[0]);
a1 = SWAP64LE(((uint64_t*) a)[1]);
b0 = SWAP64LE(((uint64_t*) b)[0]);
b1 = SWAP64LE(((uint64_t*) b)[1]);
a0 += b0;
a1 += b1;
((uint64_t*) a)[0] = SWAP64LE(a0);
((uint64_t*) a)[1] = SWAP64LE(a1);
}
bool tx_extra_message::encrypt(size_t index, const std::string &message, const AccountPublicAddress *recipient, const KeyPair &txkey) {
size_t mlen = message.size();
std::unique_ptr<char[]> buf(new char[mlen + TX_EXTRA_MESSAGE_CHECKSUM_SIZE]);
memcpy(buf.get(), message.data(), mlen);
memset(buf.get() + mlen, 0, TX_EXTRA_MESSAGE_CHECKSUM_SIZE);
mlen += TX_EXTRA_MESSAGE_CHECKSUM_SIZE;
if (recipient) {
message_key_data key_data;
if (!generate_key_derivation(recipient->spendPublicKey, txkey.secretKey, key_data.derivation)) {
return false;
}
key_data.magic1 = 0x80;
key_data.magic2 = 0;
Hash h = cn_fast_hash(&key_data, sizeof(message_key_data));
uint64_t nonce = SWAP64LE(index);
chacha(10, buf.get(), mlen, reinterpret_cast<uint8_t *>(&h), reinterpret_cast<uint8_t *>(&nonce), buf.get());
}
data.assign(buf.get(), mlen);
return true;
}
