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The spectacular complement to the Bouncy Castle crypto API for Java.
/* See LICENSE for licensing and NOTICE for copyright. */
package org.cryptacular.util;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.digests.SHA1Digest;
import org.bouncycastle.crypto.digests.SHA256Digest;
import org.bouncycastle.crypto.digests.SHA3Digest;
import org.bouncycastle.crypto.digests.SHA512Digest;
import org.cryptacular.CryptoException;
import org.cryptacular.SaltedHash;
import org.cryptacular.StreamException;
import org.cryptacular.io.Resource;
/**
* Utility class for computing cryptographic hashes.
*
* @author Middleware Services
*/
public final class HashUtil
{
/** Private constructor of utility class. */
private HashUtil() {}
/**
* Computes the hash of the given data using the given algorithm. A salted hash may be produced as follows:
*
*
// data is a byte array containing raw data to digest
final byte[] salt = new RBGNonce(16).generate();
final byte[] hash = HashUtil.hash(new SHA1Digest(), data, salt);
*
*
* @param digest Hash algorithm.
* @param data Data to hash. Supported types are byte[], {@link CharSequence} ,{@link InputStream}, and
* {@link Resource}. Character data is processed in the UTF-8 character set; if another
* character set is desired, the caller should convert to byte[] and provide the resulting
* bytes.
*
* @return Byte array of length {@link Digest#getDigestSize()} containing hash output.
*
* @throws CryptoException on hash computation errors.
* @throws StreamException on stream IO errors.
*/
public static byte[] hash(final Digest digest, final Object... data) throws CryptoException, StreamException
{
for (Object o : data) {
if (o instanceof byte[]) {
final byte[] bytes = (byte[]) o;
digest.update(bytes, 0, bytes.length);
} else if (o instanceof String) {
final byte[] bytes = ByteUtil.toBytes((String) o);
digest.update(bytes, 0, bytes.length);
} else if (o instanceof InputStream) {
hashStream(digest, (InputStream) o);
} else if (o instanceof Resource) {
final InputStream in;
try {
in = ((Resource) o).getInputStream();
} catch (IOException e) {
throw new StreamException(e);
}
hashStream(digest, in);
} else {
throw new IllegalArgumentException("Invalid input data type " + o);
}
}
final byte[] output = new byte[digest.getDigestSize()];
try {
digest.doFinal(output, 0);
} catch (RuntimeException e) {
throw new CryptoException("Hash computation error", e);
}
return output;
}
/**
* Computes the iterated hash of the given data using the given algorithm. The following example demonstrates a
* typical usage pattern, a salted hash with 10 rounds:
*
*
// data is a byte array containing raw data to digest
final byte[] salt = new RBGNonce(16).generate();
final byte[] hash = HashUtil.hash(new SHA1Digest(), 10, data, salt);
*
*
* @param digest Hash algorithm.
* @param iterations Number of hash rounds. Must be positive value.
* @param data Data to hash. Supported types are byte[], {@link CharSequence} ,{@link InputStream}, and
* {@link Resource}. Character data is processed in the UTF-8 character set; if another
* character set is desired, the caller should convert to byte[] and provide the resulting
* bytes.
*
* @return Byte array of length {@link Digest#getDigestSize()} containing hash output.
*
* @throws CryptoException on hash computation errors.
* @throws StreamException on stream IO errors.
*/
public static byte[] hash(final Digest digest, final int iterations, final Object... data)
throws CryptoException, StreamException
{
if (iterations < 1) {
throw new IllegalArgumentException("Iterations must be positive");
}
final byte[] output = hash(digest, data);
try {
for (int i = 1; i < iterations; i++) {
digest.update(output, 0, output.length);
digest.doFinal(output, 0);
}
} catch (RuntimeException e) {
throw new CryptoException("Hash computation error", e);
}
return output;
}
/**
* Determines whether the hash of the given input equals a known value.
*
* @param digest Hash algorithm.
* @param hash Hash to compare with. If the length of the array is greater than the length of the digest output,
* anything beyond the digest length is considered salt data that is hashed after the
* input data.
* @param iterations Number of hash rounds.
* @param data Data to hash.
*
* @return True if the hash of the data under the given digest is equal to the hash, false otherwise.
*
* @throws CryptoException on hash computation errors.
* @throws StreamException on stream IO errors.
*/
public static boolean compareHash(final Digest digest, final byte[] hash, final int iterations, final Object... data)
throws CryptoException, StreamException
{
if (hash.length > digest.getDigestSize()) {
final byte[] hashPart = Arrays.copyOfRange(hash, 0, digest.getDigestSize());
final byte[] saltPart = Arrays.copyOfRange(hash, digest.getDigestSize(), hash.length);
final Object[] dataWithSalt = Arrays.copyOf(data, data.length + 1);
dataWithSalt[data.length] = saltPart;
return Arrays.equals(hash(digest, iterations, dataWithSalt), hashPart);
}
return Arrays.equals(hash(digest, iterations, data), hash);
}
/**
* Determines whether the salted hash of the given input equals a known hash value.
*
* @param digest Hash algorithm.
* @param hash Salted hash data.
* @param iterations Number of hash rounds.
* @param saltAfterData True to apply salt after data, false to apply salt before data.
* @param data Data to hash, which should NOT include the salt value.
*
* @return True if the hash of the data under the given digest is equal to the hash, false otherwise.
*
* @throws CryptoException on hash computation errors.
* @throws StreamException on stream IO errors.
*/
public static boolean compareHash(
final Digest digest,
final SaltedHash hash,
final int iterations,
final boolean saltAfterData,
final Object... data)
throws CryptoException, StreamException
{
final Object[] dataWithSalt;
if (saltAfterData) {
dataWithSalt = Arrays.copyOf(data, data.length + 1);
dataWithSalt[data.length] = hash.getSalt();
} else {
dataWithSalt = new Object[data.length + 1];
dataWithSalt[0] = hash.getSalt();
System.arraycopy(data, 0, dataWithSalt, 1, data.length);
}
return Arrays.equals(hash(digest, iterations, dataWithSalt), hash.getHash());
}
/**
* Produces the SHA-1 hash of the given data.
*
* @param data Data to hash. See {@link #hash(Digest, Object...)} for supported inputs.
*
* @return 20-byte array containing hash output.
*
* @see #hash(Digest, Object...)
*/
public static byte[] sha1(final Object... data)
{
return hash(new SHA1Digest(), data);
}
/**
* Produces the SHA-256 hash of the given data.
*
* @param data Data to hash. See {@link #hash(Digest, Object...)} for supported inputs.
*
* @return 32-byte array containing hash output.
*
* @see #hash(Digest, Object...)
*/
public static byte[] sha256(final Object... data)
{
return hash(new SHA256Digest(), data);
}
/**
* Produces the SHA-512 hash of the given data.
*
* @param data Data to hash. See {@link #hash(Digest, Object...)} for supported inputs.
*
* @return 64-byte array containing hash output.
*
* @see #hash(Digest, Object...)
*/
public static byte[] sha512(final Object... data)
{
return hash(new SHA512Digest(), data);
}
/**
* Produces the SHA-3 hash of the given data.
*
* @param bitLength One of the supported SHA-3 output bit lengths: 224, 256, 384, or 512.
* @param data Data to hash. See {@link #hash(Digest, Object...)} for supported inputs.
*
* @return Byte array of size bitLength containing hash output.
*
* @see #hash(Digest, Object...)
*/
public static byte[] sha3(final int bitLength, final Object... data)
{
return hash(new SHA3Digest(bitLength), data);
}
/**
* Digests the data in the given stream. Note this method does not finalize the digest process by calling {@link
* Digest#doFinal(byte[], int)}.
*
* @param digest Digest algorithm.
* @param in Input stream containing data to hash.
*/
private static void hashStream(final Digest digest, final InputStream in)
{
final byte[] buffer = new byte[StreamUtil.CHUNK_SIZE];
int length;
try {
while ((length = in.read(buffer)) > 0) {
digest.update(buffer, 0, length);
}
} catch (IOException e) {
throw new StreamException(e);
}
}
}
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