EthereumExternalSignatureTest.java

/*
 * Copyright (C) 2019-2022 Six Clovers, Inc. - All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package com.sixclovers.external;

import static org.testng.Assert.assertNotNull;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

import org.apache.commons.codec.DecoderException;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;
import org.web3j.crypto.RawTransaction;
import org.web3j.crypto.TransactionDecoder;
import org.web3j.crypto.TransactionEncoder;
import org.web3j.utils.Numeric;

import com.algorand.algosdk.util.Encoder;
import com.sixclovers.integrations.ethereum.model.EthereumSignaturePayload;
import com.sixclovers.integrations.ethereum.model.EthereumWallet;

@SuppressWarnings("PMD")
public class EthereumExternalSignatureTest {

    /* Step 1: Provide the referenceToken and signaturePayloads from the Complete Transaction response. */

    // An opaque token to be maintained with the signature payload.
    private final String referenceToken = "PLACEHOLDER - replace with data from a TransactionPayload";

    // The list of multi-sig payloads that parties must sign.
    private final List<String> signaturePayloads = Arrays.asList("PLACEHOLDER", "replace with data from a TransactionPayload");

    /* Step 2: Provide the private key to sign transactions. */

    // The private key (the seed is held by you in a hot wallet to sign transactions).
    private final String signerPrivateKey = "PLACEHOLDER - replace with a hex encoded seed";

    private EthereumWallet wallet;

    @BeforeClass
    public void beforeClass() throws DecoderException {
        wallet = new EthereumWallet(signerPrivateKey);
    }

    @Test
    public void testEthereumExternalSignatureTransaction() {
        /* Step 3: Decode the signaturePayloads given by the transaction request. */
        final List<EthereumSignaturePayload> decodedTransactions = decodeSignaturePayloads(signaturePayloads);

        /* Step 4: Verify and sign each transaction. */
        final List<EthereumSignaturePayload> signedTransactions = signTransactions(decodedTransactions);

        /* Step 5: Encode the objects so that we may send them to the Commit Transaction endpoint. */
        final List<String> encodedTransactions = encodeTransactions(signedTransactions);

        assertNotNull(referenceToken);
        assertNotNull(encodedTransactions);

        /* Step 6: Submit the values to the Commit Transaction endpoint. */
        System.out.println("referenceToken: " + encodeToJson(referenceToken));
        System.out.println("signaturePayloads: " + encodeToJson(encodedTransactions));
    }

    private byte[] decodeFromBase64(final String value) {
        return Encoder.decodeFromBase64(value);
    }

    private <T> T decodeFromJson(final String value, final Class<T> clazz) {
        try {
            return Encoder.decodeFromJson(value, clazz);
        } catch (final Exception e) {
            // We never expect this to happen in live code, but to make test failures obvious, we throw a RuntimeException.
            // Log.error(e);
            // return null;
            throw new RuntimeException(e);
        }
    }

    private List<EthereumSignaturePayload> decodeSignaturePayloads(final List<String> payloads) {
        final List<EthereumSignaturePayload> decodedTransactions = new LinkedList<>();
        for (final String payload : payloads) {
            decodedTransactions.add(decodeFromJson(new String(decodeFromBase64(payload)), EthereumSignaturePayload.class));
        }
        return decodedTransactions;
    }

    private String encodeToBase64(final byte[] bytes) {
        return Encoder.encodeToBase64(bytes);
    }

    private String encodeToJson(final Object object) {
        try {
            return Encoder.encodeToJson(object);
        } catch (final Exception e) {
            // We never expect this to happen in live code, but to make test failures obvious, we throw a RuntimeException.
            // Log.error(e);
            // return null;
            throw new RuntimeException(e);
        }
    }

    private List<String> encodeTransactions(final List<EthereumSignaturePayload> payloads) {
        final List<String> encodedTransactions = new LinkedList<>();
        for (final EthereumSignaturePayload payload : payloads) {
            encodedTransactions.add(encodeToBase64(encodeToJson(payload).getBytes()));
        }
        return encodedTransactions;
    }

    private List<EthereumSignaturePayload> signTransactions(final List<EthereumSignaturePayload> payloads) {
        final List<EthereumSignaturePayload> signedTransactions = new LinkedList<>();
        for (final EthereumSignaturePayload payload : payloads) {
            if (payload.getFrom().equals(wallet.getAddress())) {
                // Sign the transaction.
                final RawTransaction rawTransaction = TransactionDecoder.decode(payload.getTransaction());
                final byte[] signedMessage = TransactionEncoder.signMessage(rawTransaction, wallet.getCredentials());
                payload.setTransaction(Numeric.toHexString(signedMessage));

                // Store the signed transaction.
                signedTransactions.add(payload);
            } else {
                // Store the same transaction unsigned. It belongs to the same transaction group and will be signed by someone else.
                signedTransactions.add(payload);
            }
        }
        return signedTransactions;
    }

}

EthereumSignaturePayload.java

/*
 * Copyright (C) 2019-2022 Six Clovers, Inc. - All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package com.sixclovers.integrations.ethereum.model;

import lombok.Data;

@Data
public class EthereumSignaturePayload {

    private String from;

    private String transaction;

}

EthereumWallet.java

/*
 * Copyright (C) 2019-2022 Six Clovers, Inc. - All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package com.sixclovers.integrations.ethereum.model;

import java.math.BigInteger;
import java.security.InvalidAlgorithmParameterException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;
import org.web3j.crypto.Credentials;
import org.web3j.crypto.ECKeyPair;
import org.web3j.crypto.Keys;

import lombok.Data;

@Data
public class EthereumWallet {

    private final String address;

    private final Credentials credentials;

    private final ECKeyPair ecKeyPair;

    private final String seed;

    public EthereumWallet() throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, NoSuchProviderException {
        this(Keys.createEcKeyPair());
    }

    public EthereumWallet(final String seed) throws DecoderException {
        this(ECKeyPair.create(new BigInteger(Hex.decodeHex(seed))));
    }

    public EthereumWallet(final String address, final String seed) {
        this.address = address;
        this.seed = seed;
        credentials = null;
        ecKeyPair = null;
    }

    private EthereumWallet(final ECKeyPair ecKeyPair) {
        final Credentials credentials = Credentials.create(ecKeyPair);
        address = credentials.getAddress();
        this.credentials = credentials;
        this.ecKeyPair = ecKeyPair;
        seed = Hex.encodeHexString(ecKeyPair.getPrivateKey().toByteArray());
    }

}