Examples with Hasher io.nem.symbol.core.crypto.Hasher used on opensource projects

Example 1 with Hasher

use of io.nem.symbol.core.crypto.Hasher in project nem2-sdk-java by nemtech.

the class Ed25519DsaSigner method sign.

@Override
@SuppressWarnings("squid:S00117")
public Signature sign(final byte[] data) {
    if (!this.getKeyPair().hasPrivateKey()) {
        throw new CryptoException("cannot sign without private key");
    }
    Hasher hasher32 = Hashes::sha512;
    Hasher hasher64 = Hashes::sha512;
    // Hash the private key to improve randomness.
    final byte[] hash = hasher32.hash(this.getKeyPair().getPrivateKey().getBytes());
    // r = H(hash_b,...,hash_2b-1, data) where b=256.
    final Ed25519EncodedFieldElement r = new Ed25519EncodedFieldElement(hasher64.hash(// only
    Arrays.copyOfRange(hash, 32, 64), // key hash
    data));
    // Reduce size of r since we are calculating mod group order anyway
    final Ed25519EncodedFieldElement rModQ = r.modQ();
    // R = rModQ * base point.
    final Ed25519GroupElement R = Ed25519Group.BASE_POINT.scalarMultiply(rModQ);
    final Ed25519EncodedGroupElement encodedR = R.encode();
    // S = (r + H(encodedR, encodedA, data) * a) mod group order where
    // encodedR and encodedA are the little endian encodings of the group element R
    // and the
    // public
    // key A and
    // a is the lower 32 bytes of hash after clamping.
    final Ed25519EncodedFieldElement h = new Ed25519EncodedFieldElement(hasher64.hash(encodedR.getRaw(), this.getKeyPair().getPublicKey().getBytes(), data));
    final Ed25519EncodedFieldElement hModQ = h.modQ();
    final Ed25519EncodedFieldElement encodedS = hModQ.multiplyAndAddModQ(Ed25519Utils.prepareForScalarMultiply(this.getKeyPair().getPrivateKey()), rModQ);
    // Signature is (encodedR, encodedS)
    final Signature signature = new Signature(encodedR.getRaw(), encodedS.getRaw());
    if (!this.isCanonicalSignature(signature)) {
        throw new CryptoException("Generated signature is not canonical");
    }
    return signature;
}

Example 2 with Hasher

use of io.nem.symbol.core.crypto.Hasher in project nem2-sdk-java by nemtech.

the class Ed25519DsaSigner method verify.

@Override
public boolean verify(final byte[] data, final Signature signature) {
    if (!this.isCanonicalSignature(signature)) {
        return false;
    }
    if (1 == ArrayUtils.isEqualConstantTime(this.getKeyPair().getPublicKey().getBytes(), new byte[32])) {
        return false;
    }
    Hasher hasher64 = Hashes::sha512;
    // h = H(encodedR, encodedA, data).
    final byte[] rawEncodedR = signature.getBinaryR();
    final byte[] rawEncodedA = this.getKeyPair().getPublicKey().getBytes();
    final Ed25519EncodedFieldElement h = new Ed25519EncodedFieldElement(hasher64.hash(rawEncodedR, rawEncodedA, data));
    // hReduced = h mod group order
    final Ed25519EncodedFieldElement hModQ = h.modQ();
    // Must compute A.
    final Ed25519GroupElement a = new Ed25519EncodedGroupElement(rawEncodedA).decode();
    a.precomputeForDoubleScalarMultiplication();
    // R = encodedS * B - H(encodedR, encodedA, data) * A
    final Ed25519GroupElement calculatedR = Ed25519Group.BASE_POINT.doubleScalarMultiplyVariableTime(a, hModQ, new Ed25519EncodedFieldElement(signature.getBinaryS()));
    // Compare calculated R to given R.
    final byte[] encodedCalculatedR = calculatedR.encode().getRaw();
    final int result = ArrayUtils.isEqualConstantTime(encodedCalculatedR, rawEncodedR);
    return 1 == result;
}

Example 3 with Hasher

use of io.nem.symbol.core.crypto.Hasher in project nem2-sdk-java by nemtech.

the class MathUtils method sign.

/**
 * Creates a signature from a key pair and message.
 *
 * @param keyPair The key pair.
 * @param data The message.
 * @return The signature.
 */
public static Signature sign(final KeyPair keyPair, final byte[] data) {
    Hasher hasher64 = Hashes::sha512;
    Hasher hasher32 = Hashes::sha512;
    final byte[] hash = hasher32.hash(keyPair.getPrivateKey().getBytes());
    final byte[] a = Arrays.copyOfRange(hash, 0, 32);
    a[31] &= 0x7F;
    a[31] |= 0x40;
    a[0] &= 0xF8;
    final Ed25519EncodedFieldElement r = new Ed25519EncodedFieldElement(hasher64.hash(Arrays.copyOfRange(hash, 32, 64), data));
    final Ed25519EncodedFieldElement rReduced = reduceModGroupOrder(r);
    final Ed25519GroupElement R = scalarMultiplyGroupElement(Ed25519Group.BASE_POINT, toFieldElement(toBigInteger(rReduced)));
    final Ed25519EncodedFieldElement h = new Ed25519EncodedFieldElement(hasher64.hash(R.encode().getRaw(), keyPair.getPublicKey().getBytes(), data));
    final Ed25519EncodedFieldElement hReduced = reduceModGroupOrder(h);
    final BigInteger S = toBigInteger(rReduced).add(toBigInteger(hReduced).multiply(toBigInteger(a))).mod(Ed25519Group.GROUP_ORDER);
    return new Signature(R.encode().getRaw(), toByteArray(S));
}

Example 4 with Hasher

use of io.nem.symbol.core.crypto.Hasher in project nem2-sdk-java by nemtech.

the class AggregateTransactionFactory method calculateTransactionsHash.

/**
 * It generates the hash of the transactions that are going to be included in the {@link
 * AggregateTransaction}
 *
 * @param transactions the inner transaction
 * @return the added transaction hash.
 */
private static String calculateTransactionsHash(final List<Transaction> transactions) {
    final MerkleHashBuilder transactionsHashBuilder = new MerkleHashBuilder();
    final BinarySerializationImpl transactionSerialization = new BinarySerializationImpl();
    Hasher hasher = Hashes::sha3_256;
    for (final Transaction transaction : transactions) {
        final byte[] bytes = transactionSerialization.serializeEmbedded(transaction);
        byte[] transactionHash = hasher.hash(bytes);
        transactionsHashBuilder.update(transactionHash);
    }
    final byte[] hash = transactionsHashBuilder.getRootHash();
    return ConvertUtils.toHex(hash);
}