io.nuls.core.crypto.Sha256Hash Maven / Gradle / Ivy
/*
* MIT License
*
* Copyright (c) 2017-2018 nuls.io
*
* 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 io.nuls.core.crypto;
import io.nuls.core.model.ByteUtils;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.Serializable;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
/**
* A Sha256Hash just wraps a byte[] so that equals and hashcode work correctly, allowing it to be used as keys in a
* map. It also checks that the length is correct and provides a bit more type safety.
* @author
*/
public class Sha256Hash implements Serializable, Comparable {
private static final long serialVersionUID = 3986948258337764647L;
/**
* bytes
**/
public static final int LENGTH = 32;
public static final Sha256Hash ZERO_HASH = wrap(new byte[LENGTH]);
private final byte[] bytes;
@Deprecated
public Sha256Hash(byte[] rawHashBytes) {
HexUtil.checkState(rawHashBytes.length == LENGTH);
this.bytes = rawHashBytes;
}
@Deprecated
public Sha256Hash(String hexString) {
HexUtil.checkState(hexString.length() == LENGTH * 2);
this.bytes = HexUtil.decode(hexString);
}
/**
* Creates a new instance that wraps the given hash value.
*
* @param rawHashBytes the raw hash bytes to wrap
* @return a new instance
* @throws IllegalArgumentException if the given array length is not exactly 32
*/
public static Sha256Hash wrap(byte[] rawHashBytes) {
return new Sha256Hash(rawHashBytes);
}
/**
* Creates a new instance that wraps the given hash value (represented as a hex string).
*
* @param hexString a hash value represented as a hex string
* @return a new instance
* @throws IllegalArgumentException if the given string is not a valid
* hex string, or if it does not represent exactly 32 bytes
*/
public static Sha256Hash wrap(String hexString) {
return wrap(HexUtil.decode(hexString));
}
/**
* Creates a new instance that wraps the given hash value, but with byte order reversed.
*
* @param rawHashBytes the raw hash bytes to wrap
* @return a new instance
* @throws IllegalArgumentException if the given array length is not exactly 32
*/
public static Sha256Hash wrapReversed(byte[] rawHashBytes) {
return wrap(ByteUtils.reverseBytes(rawHashBytes));
}
@Deprecated
public static Sha256Hash create(byte[] contents) {
return of(contents);
}
/**
* Creates a new instance containing the calculated (one-time) hash of the given bytes.
*
* @param contents the bytes on which the hash value is calculated
* @return a new instance containing the calculated (one-time) hash
*/
public static Sha256Hash of(byte[] contents) {
return wrap(hash(contents));
}
@Deprecated
public static Sha256Hash createDouble(byte[] contents) {
return twiceOf(contents);
}
/**
* Creates a new instance containing the hash of the calculated hash of the given bytes.
*
* @param contents the bytes on which the hash value is calculated
* @return a new instance containing the calculated (two-time) hash
*/
public static Sha256Hash twiceOf(byte[] contents) {
return wrap(hashTwice(contents));
}
/**
* Creates a new instance containing the calculated (one-time) hash of the given file's contents.
*
* The file contents are read fully into memory, so this method should only be used with small files.
*
* @param file the file on which the hash value is calculated
* @return a new instance containing the calculated (one-time) hash
* @throws IOException if an error occurs while reading the file
*/
public static Sha256Hash of(File file) throws IOException {
FileInputStream in = new FileInputStream(file);
try {
return of(ByteStreams.toByteArray(in));
} finally {
in.close();
}
}
/**
* Returns a new SHA-256 MessageDigest instance.
*
* This is a convenience method which wraps the checked
* exception that can never occur with a RuntimeException.
*
* @return a new SHA-256 MessageDigest instance
*/
public static MessageDigest newDigest() {
try {
return MessageDigest.getInstance("SHA-256");
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e); // Can't happen.
}
}
/**
* Calculates the SHA-256 hash of the given bytes.
*
* @param input the bytes to hash
* @return the hash (in big-endian order)
*/
public static byte[] hash(byte[] input) {
return hash(input, 0, input.length);
}
/**
* Calculates the SHA-256 hash of the given byte range.
*
* @param input the array containing the bytes to hash
* @param offset the offset within the array of the bytes to hash
* @param length the number of bytes to hash
* @return the hash (in big-endian order)
*/
public static byte[] hash(byte[] input, int offset, int length) {
MessageDigest digest = newDigest();
digest.update(input, offset, length);
return digest.digest();
}
/**
* Calculates the SHA-256 hash of the given bytes,
* and then hashes the resulting hash again.
*
* @param input the bytes to hash
* @return the double-hash (in big-endian order)
*/
public static byte[] hashTwice(byte[] input) {
return hashTwice(input, 0, input.length);
}
/**
* Calculates the SHA-256 hash of the given byte range,
* and then hashes the resulting hash again.
*
* @param input the array containing the bytes to hash
* @param offset the offset within the array of the bytes to hash
* @param length the number of bytes to hash
* @return the double-hash (in big-endian order)
*/
public static byte[] hashTwice(byte[] input, int offset, int length) {
MessageDigest digest = newDigest();
digest.update(input, offset, length);
return digest.digest(digest.digest());
}
public static byte[] hashTwice(byte[] input1, int offset1, int length1,
byte[] input2, int offset2, int length2) {
MessageDigest digest = newDigest();
digest.update(input1, offset1, length1);
digest.update(input2, offset2, length2);
return digest.digest(digest.digest());
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
return Arrays.equals(bytes, ((Sha256Hash) o).bytes);
}
/**
* Returns the last four bytes of the wrapped hash. This should be unique enough to be a suitable hash code even for
* blocks, where the goal is to try and get the first bytes to be zeros (i.e. the value as a big integer lower
* than the target value).
*
* @return int
*/
@Override
public int hashCode() {
// Use the last 4 bytes, not the first 4 which are often zeros in Bitcoin.
return ByteUtils.bytesToInt(ByteUtils.reverseBytes(Arrays.copyOfRange(bytes,bytes.length-4,bytes.length)));
}
@Override
public String toString() {
return HexUtil.encode(bytes);
}
/**
* Returns the bytes interpreted as a positive integer.
*
* @return BigInteger
*/
public BigInteger toBigInteger() {
return new BigInteger(1, bytes);
}
/**
* Returns the internal byte array, without defensively copying. Therefore do NOT modify the returned array.
*
* @return byte[]
*/
public byte[] getBytes() {
return bytes;
}
/**
* Returns a reversed copy of the internal byte array.
*
* @return byte[]
*/
public byte[] getReversedBytes() {
return ByteUtils.reverseBytes(bytes);
}
@Override
public int compareTo(final Sha256Hash other) {
for (int i = LENGTH - 1; i >= 0; i--) {
final int thisByte = this.bytes[i] & 0xff;
final int otherByte = other.bytes[i] & 0xff;
if (thisByte > otherByte) {
return 1;
}
if (thisByte < otherByte) {
return -1;
}
}
return 0;
}
}