forked from Qortal/qortal
catbref
4 years ago
16 changed files with 351 additions and 377 deletions
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package org.qortal.crosschain; |
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import java.util.List; |
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import java.util.function.Function; |
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import org.bitcoinj.core.Address; |
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import org.bitcoinj.core.Coin; |
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import org.bitcoinj.core.ECKey; |
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import org.bitcoinj.core.LegacyAddress; |
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import org.bitcoinj.core.NetworkParameters; |
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import org.bitcoinj.core.Transaction; |
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import org.bitcoinj.core.Transaction.SigHash; |
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import org.bitcoinj.core.TransactionInput; |
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import org.bitcoinj.core.TransactionOutput; |
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import org.bitcoinj.crypto.TransactionSignature; |
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import org.bitcoinj.script.Script; |
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import org.bitcoinj.script.ScriptBuilder; |
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import org.bitcoinj.script.ScriptChunk; |
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import org.bitcoinj.script.ScriptOpCodes; |
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import org.qortal.crypto.Crypto; |
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import org.qortal.utils.BitTwiddling; |
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import com.google.common.hash.HashCode; |
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import com.google.common.primitives.Bytes; |
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public class BTCP2SH { |
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public static final int SECRET_LENGTH = 32; |
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public static final int MIN_LOCKTIME = 1500000000; |
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/* |
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* OP_TUCK (to copy public key to before signature) |
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* OP_CHECKSIGVERIFY (sig & pubkey must verify or script fails) |
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* OP_HASH160 (convert public key to PKH) |
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* OP_DUP (duplicate PKH) |
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* <push 20 bytes> <refund PKH> OP_EQUAL (does PKH match refund PKH?) |
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* OP_IF |
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* OP_DROP (no need for duplicate PKH) |
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* <push 4 bytes> <locktime> |
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* OP_CHECKLOCKTIMEVERIFY (if this passes, leftover stack is <locktime> so script passes) |
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* OP_ELSE |
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* <push 20 bytes> <redeem PKH> OP_EQUALVERIFY (duplicate PKH must match redeem PKH or script fails) |
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* OP_HASH160 (hash secret) |
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* <push 20 bytes> <hash of secret> OP_EQUAL (do hashes of secrets match? if true, script passes else script fails) |
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* OP_ENDIF |
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*/ |
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private static final byte[] redeemScript1 = HashCode.fromString("7dada97614").asBytes(); // OP_TUCK OP_CHECKSIGVERIFY OP_HASH160 OP_DUP push(0x14 bytes)
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private static final byte[] redeemScript2 = HashCode.fromString("87637504").asBytes(); // OP_EQUAL OP_IF OP_DROP push(0x4 bytes)
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private static final byte[] redeemScript3 = HashCode.fromString("b16714").asBytes(); // OP_CHECKLOCKTIMEVERIFY OP_ELSE push(0x14 bytes)
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private static final byte[] redeemScript4 = HashCode.fromString("88a914").asBytes(); // OP_EQUALVERIFY OP_HASH160 push(0x14 bytes)
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private static final byte[] redeemScript5 = HashCode.fromString("8768").asBytes(); // OP_EQUAL OP_ENDIF
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/** |
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* Returns Bitcoin redeemScript used for cross-chain trading. |
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* <p> |
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* See comments in {@link BTCP2SH} for more details. |
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* |
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* @param refunderPubKeyHash 20-byte HASH160 of P2SH funder's public key, for refunding purposes |
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* @param lockTime seconds-since-epoch threshold, after which P2SH funder can claim refund |
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* @param redeemerPubKeyHash 20-byte HASH160 of P2SH redeemer's public key |
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* @param secretHash 20-byte HASH160 of secret, used by P2SH redeemer to claim funds |
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* @return |
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*/ |
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public static byte[] buildScript(byte[] refunderPubKeyHash, int lockTime, byte[] redeemerPubKeyHash, byte[] secretHash) { |
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return Bytes.concat(redeemScript1, refunderPubKeyHash, redeemScript2, BitTwiddling.toLEByteArray((int) (lockTime & 0xffffffffL)), |
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redeemScript3, redeemerPubKeyHash, redeemScript4, secretHash, redeemScript5); |
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} |
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/** |
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* Builds a custom transaction to spend P2SH. |
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* |
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* @param amount output amount, should be total of input amounts, less miner fees |
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* @param spendKey key for signing transaction, and also where funds are 'sent' (output) |
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* @param fundingOutput output from transaction that funded P2SH address |
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* @param redeemScriptBytes the redeemScript itself, in byte[] form |
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* @param lockTime (optional) transaction nLockTime, used in refund scenario |
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* @param scriptSigBuilder function for building scriptSig using transaction input signature |
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* @return Signed Bitcoin transaction for spending P2SH |
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*/ |
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public static Transaction buildP2shTransaction(Coin amount, ECKey spendKey, List<TransactionOutput> fundingOutputs, byte[] redeemScriptBytes, Long lockTime, Function<byte[], Script> scriptSigBuilder) { |
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NetworkParameters params = BTC.getInstance().getNetworkParameters(); |
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Transaction transaction = new Transaction(params); |
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transaction.setVersion(2); |
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// Output is back to P2SH funder
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transaction.addOutput(amount, ScriptBuilder.createP2PKHOutputScript(spendKey.getPubKeyHash())); |
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for (int inputIndex = 0; inputIndex < fundingOutputs.size(); ++inputIndex) { |
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TransactionOutput fundingOutput = fundingOutputs.get(inputIndex); |
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// Input (without scriptSig prior to signing)
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TransactionInput input = new TransactionInput(params, null, redeemScriptBytes, fundingOutput.getOutPointFor()); |
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if (lockTime != null) |
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input.setSequenceNumber(BTC.LOCKTIME_NO_RBF_SEQUENCE); // Use max-value, so no lockTime and no RBF
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else |
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input.setSequenceNumber(BTC.NO_LOCKTIME_NO_RBF_SEQUENCE); // Use max-value - 1, so lockTime can be used but not RBF
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transaction.addInput(input); |
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} |
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// Set locktime after inputs added but before input signatures are generated
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if (lockTime != null) |
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transaction.setLockTime(lockTime); |
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for (int inputIndex = 0; inputIndex < fundingOutputs.size(); ++inputIndex) { |
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// Generate transaction signature for input
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final boolean anyoneCanPay = false; |
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TransactionSignature txSig = transaction.calculateSignature(inputIndex, spendKey, redeemScriptBytes, SigHash.ALL, anyoneCanPay); |
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// Calculate transaction signature
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byte[] txSigBytes = txSig.encodeToBitcoin(); |
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// Build scriptSig using lambda and tx signature
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Script scriptSig = scriptSigBuilder.apply(txSigBytes); |
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// Set input scriptSig
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transaction.getInput(inputIndex).setScriptSig(scriptSig); |
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} |
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return transaction; |
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} |
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/** |
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* Returns signed Bitcoin transaction claiming refund from P2SH address. |
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* |
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* @param refundAmount refund amount, should be total of input amounts, less miner fees |
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* @param refundKey key for signing transaction, and also where refund is 'sent' (output) |
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* @param fundingOutput output from transaction that funded P2SH address |
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* @param redeemScriptBytes the redeemScript itself, in byte[] form |
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* @param lockTime transaction nLockTime - must be at least locktime used in redeemScript |
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* @return Signed Bitcoin transaction for refunding P2SH |
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*/ |
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public static Transaction buildRefundTransaction(Coin refundAmount, ECKey refundKey, List<TransactionOutput> fundingOutputs, byte[] redeemScriptBytes, long lockTime) { |
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Function<byte[], Script> refundSigScriptBuilder = (txSigBytes) -> { |
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// Build scriptSig with...
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ScriptBuilder scriptBuilder = new ScriptBuilder(); |
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// transaction signature
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scriptBuilder.addChunk(new ScriptChunk(txSigBytes.length, txSigBytes)); |
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// redeem public key
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byte[] refundPubKey = refundKey.getPubKey(); |
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scriptBuilder.addChunk(new ScriptChunk(refundPubKey.length, refundPubKey)); |
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// redeem script
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scriptBuilder.addChunk(new ScriptChunk(ScriptOpCodes.OP_PUSHDATA1, redeemScriptBytes)); |
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return scriptBuilder.build(); |
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}; |
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return buildP2shTransaction(refundAmount, refundKey, fundingOutputs, redeemScriptBytes, lockTime, refundSigScriptBuilder); |
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} |
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/** |
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* Returns signed Bitcoin transaction redeeming funds from P2SH address. |
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* |
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* @param redeemAmount redeem amount, should be total of input amounts, less miner fees |
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* @param redeemKey key for signing transaction, and also where funds are 'sent' (output) |
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* @param fundingOutput output from transaction that funded P2SH address |
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* @param redeemScriptBytes the redeemScript itself, in byte[] form |
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* @param secret actual 32-byte secret used when building redeemScript |
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* @return Signed Bitcoin transaction for redeeming P2SH |
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*/ |
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public static Transaction buildRedeemTransaction(Coin redeemAmount, ECKey redeemKey, List<TransactionOutput> fundingOutputs, byte[] redeemScriptBytes, byte[] secret) { |
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Function<byte[], Script> redeemSigScriptBuilder = (txSigBytes) -> { |
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// Build scriptSig with...
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ScriptBuilder scriptBuilder = new ScriptBuilder(); |
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// secret
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scriptBuilder.addChunk(new ScriptChunk(secret.length, secret)); |
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// transaction signature
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scriptBuilder.addChunk(new ScriptChunk(txSigBytes.length, txSigBytes)); |
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// redeem public key
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byte[] redeemPubKey = redeemKey.getPubKey(); |
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scriptBuilder.addChunk(new ScriptChunk(redeemPubKey.length, redeemPubKey)); |
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// redeem script
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scriptBuilder.addChunk(new ScriptChunk(ScriptOpCodes.OP_PUSHDATA1, redeemScriptBytes)); |
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return scriptBuilder.build(); |
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}; |
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return buildP2shTransaction(redeemAmount, redeemKey, fundingOutputs, redeemScriptBytes, null, redeemSigScriptBuilder); |
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} |
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/** Returns 'secret', if any, given list of raw bitcoin transactions. */ |
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public static byte[] findP2shSecret(String p2shAddress, List<byte[]> rawTransactions) { |
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NetworkParameters params = BTC.getInstance().getNetworkParameters(); |
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for (byte[] rawTransaction : rawTransactions) { |
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Transaction transaction = new Transaction(params, rawTransaction); |
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// Cycle through inputs, looking for one that spends our P2SH
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for (TransactionInput input : transaction.getInputs()) { |
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Script scriptSig = input.getScriptSig(); |
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List<ScriptChunk> scriptChunks = scriptSig.getChunks(); |
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// Expected number of script chunks for redeem. Refund might not have the same number.
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int expectedChunkCount = 1 /*secret*/ + 1 /*sig*/ + 1 /*pubkey*/ + 1 /*redeemScript*/; |
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if (scriptChunks.size() != expectedChunkCount) |
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continue; |
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// We're expecting last chunk to contain the actual redeemScript
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ScriptChunk lastChunk = scriptChunks.get(scriptChunks.size() - 1); |
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byte[] redeemScriptBytes = lastChunk.data; |
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// If non-push scripts, redeemScript will be null
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if (redeemScriptBytes == null) |
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continue; |
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byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes); |
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Address inputAddress = LegacyAddress.fromScriptHash(params, redeemScriptHash); |
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if (!inputAddress.toString().equals(p2shAddress)) |
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// Input isn't spending our P2SH
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continue; |
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byte[] secret = scriptChunks.get(0).data; |
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if (secret.length != BTCP2SH.SECRET_LENGTH) |
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continue; |
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return secret; |
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} |
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} |
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return null; |
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} |
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} |
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