Fix incorrect PoW buffer length usage

src/main/java/org/qortal/crypto/MemoryPoW.java

@@ -2,85 +2,8 @@ package org.qortal.crypto;
 
 import java.nio.ByteBuffer;
 
-import com.google.common.primitives.Bytes;
-
 public class MemoryPoW {
 
-	private static final int HASH_LENGTH = 32;
-	private static final int HASH_LENGTH_MASK = HASH_LENGTH - 1;
-
-	public static Integer compute(byte[] data, int workBufferLength, int start, int range, int difficulty) {
-		if (range < 1)
-			throw new IllegalArgumentException("range must be at least 1");
-
-		if (difficulty < 1)
-			throw new IllegalArgumentException("difficulty must be at least 1");
-
-		final int workBufferLengthMask = workBufferLength - 1;
-
-		// Hash data with SHA256
-		byte[] hash = Crypto.digest(data);
-
-		assert hash.length == HASH_LENGTH;
-
-		byte[] perturbedHash = new byte[HASH_LENGTH];
-		byte[] workBuffer = new byte[workBufferLength];
-		byte[] bufferHash = new byte[HASH_LENGTH];
-
-		// For each nonce...
-		for (int nonce = start; nonce < start + range; ++nonce) {
-			// Perturb hash using nonce
-			int temp = nonce;
-			for (int hi = 0; hi < HASH_LENGTH; ++hi) {
-				perturbedHash[hi] = (byte) (hash[hi] ^ (temp & 0xff));
-				temp >>>= 1;
-			}
-
-			// Fill large working memory buffer using hash, further perturbing as we go
-			int wanderingBufferOffset = 0;
-			byte ch = 0;
-
-			int hashOffset = 0;
-
-			for (int workBufferOffset = 0; workBufferOffset < workBufferLength; workBufferOffset += HASH_LENGTH) {
-				System.arraycopy(perturbedHash, 0, workBuffer, workBufferOffset, HASH_LENGTH);
-
-				hashOffset = ++hashOffset & HASH_LENGTH_MASK;
-
-				ch += perturbedHash[hashOffset];
-
-				for (byte hi = 0; hi < HASH_LENGTH; ++hi) {
-					byte hashByte = perturbedHash[hi];
-					wanderingBufferOffset = (wanderingBufferOffset << 3) ^ (hashByte & 0xff);
-
-					perturbedHash[hi] = (byte) (hashByte ^ (ch + hi));
-				}
-
-				workBuffer[wanderingBufferOffset & workBufferLengthMask] ^= 0xAA;
-
-				// final int finalWanderingBufferOffset = wanderingBufferOffset & WORK_BUFFER_LENGTH_MASK;
-				// System.out.println(String.format("wanderingBufferOffset: 0x%08x / 0x%08x - %02d%%", finalWanderingBufferOffset, WORK_BUFFER_LENGTH, finalWanderingBufferOffset * 100 / WORK_BUFFER_LENGTH));
-			}
-
-			Bytes.reverse(workBuffer);
-
-			// bufferHash = Crypto.digest(workBuffer);
-			System.arraycopy(workBuffer, 0, bufferHash, 0, HASH_LENGTH);
-
-			int hi = 0;
-			for (hi = 0; hi < difficulty; ++hi)
-				if (bufferHash[hi] != 0)
-					break;
-
-			if (hi == difficulty)
-				return nonce;
-
-			Thread.yield();
-		}
-
-		return null;
-	}
-
 	public static Integer compute2(byte[] data, int workBufferLength, long difficulty) {
 		// Hash data with SHA256
 		byte[] hash = Crypto.digest(data);
@@ -94,7 +17,7 @@ public class MemoryPoW {
 		byteBuffer = null;
 
 		int longBufferLength = workBufferLength / 8;
-		long[] workBuffer = new long[longBufferLength / 8];
+		long[] workBuffer = new long[longBufferLength];
 		long[] state = new long[4];
 
 		long seed = 8682522807148012L;

src/main/wasm/memory-pow/memory-pow.c

@@ -4,7 +4,6 @@
 	typedef unsigned long long uint64_t;
 #endif
 
-#define WORKBUFFER_LENGTH (longBufferLength / 8)
 #define INTEGER_MAX_VALUE 0x7fffffffULL
 
 uint64_t xoshiro256p(uint64_t state[]) {
@@ -71,13 +70,13 @@ uint32_t compute2(uint8_t *hash, uint64_t *workBuffer, uint32_t workBufferLength
 		state[3] = longHash[3] ^ seed;
 
 		// Fill work buffer with random
-		for (uint32_t i = 0; i < WORKBUFFER_LENGTH; ++i)
+		for (uint32_t i = 0; i < longBufferLength; ++i)
 			workBuffer[i] = xoshiro256p(state);
 
 		// Random bounce through whole buffer
 		result = workBuffer[0];
 		for (uint32_t i = 0; i < 1024; ++i) {
-			uint32_t index = (uint32_t) (xoshiro256p(state) & INTEGER_MAX_VALUE) % WORKBUFFER_LENGTH;
+			uint32_t index = (uint32_t) (xoshiro256p(state) & INTEGER_MAX_VALUE) % longBufferLength;
 			result ^= workBuffer[index];
 		}