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Derive PoW difficulty from the file size. Exact values TBC.

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This commit is contained in:
CalDescent
2021-07-13 22:18:21 +01:00
parent 00d4f35f2c
commit 9384a50879
2 changed files with 80 additions and 3 deletions
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18
src/main/java/org/qortal/transaction/ArbitraryTransaction.java
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@@ -1,5 +1,6 @@
package org.qortal.transaction;
import java.math.BigInteger;
import java.util.List;
import java.util.stream.Collectors;
@@ -28,7 +29,9 @@ public class ArbitraryTransaction extends Transaction {
public static final int MAX_CHUNK_HASHES_LENGTH = 8000;
public static final int HASH_LENGTH = TransactionTransformer.SHA256_LENGTH;
public static final int POW_BUFFER_SIZE = 8 * 1024 * 1024; // bytes
public static final int POW_DIFFICULTY = 10; // leading zero bits
public static final int POW_MIN_DIFFICULTY = 12; // leading zero bits
public static final int POW_MAX_DIFFICULTY = 19; // leading zero bits
public static final long MAX_FILE_SIZE = DataFile.MAX_FILE_SIZE;
// Constructors
@@ -65,7 +68,7 @@ public class ArbitraryTransaction extends Transaction {
// Clear nonce from transactionBytes
ArbitraryTransactionTransformer.clearNonce(transactionBytes);
int difficulty = POW_DIFFICULTY;
int difficulty = difficultyForFileSize(arbitraryTransactionData.getSize());
// Calculate nonce
this.arbitraryTransactionData.setNonce(MemoryPoW.compute2(transactionBytes, POW_BUFFER_SIZE, difficulty));
@@ -155,7 +158,7 @@ public class ArbitraryTransaction extends Transaction {
// Clear nonce from transactionBytes
ArbitraryTransactionTransformer.clearNonce(transactionBytes);
int difficulty = POW_DIFFICULTY;
int difficulty = difficultyForFileSize(arbitraryTransactionData.getSize());
// Check nonce
return MemoryPoW.verify2(transactionBytes, POW_BUFFER_SIZE, difficulty, nonce);
@@ -213,4 +216,13 @@ public class ArbitraryTransaction extends Transaction {
return null;
}
// Helper methods
public int difficultyForFileSize(long size) {
final BigInteger powRange = BigInteger.valueOf(POW_MAX_DIFFICULTY - POW_MIN_DIFFICULTY);
final BigInteger multiplier = BigInteger.valueOf(100);
final BigInteger percentage = BigInteger.valueOf(size).multiply(multiplier).divide(BigInteger.valueOf(MAX_FILE_SIZE));
return POW_MIN_DIFFICULTY + powRange.multiply(percentage).divide(multiplier).intValue();
}
}