org.cryptacular.util

Class HashUtil

java.lang.Object

org.cryptacular.util.HashUtil

public final class HashUtil
extends java.lang.Object

Utility class for computing cryptographic hashes.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	HashUtil() Private constructor of utility class.

Method Summary

Modifier and Type	Method and Description
static boolean	compareHash(org.bouncycastle.crypto.Digest digest, byte[] hash, int iterations, java.lang.Object... data) Determines whether the hash of the given input equals a known value.
static boolean	compareHash(org.bouncycastle.crypto.Digest digest, SaltedHash hash, int iterations, boolean saltAfterData, java.lang.Object... data) Determines whether the salted hash of the given input equals a known hash value.
static byte[]	hash(org.bouncycastle.crypto.Digest digest, int iterations, java.lang.Object... data) Computes the iterated hash of the given data using the given algorithm.
static byte[]	hash(org.bouncycastle.crypto.Digest digest, java.lang.Object... data) Computes the hash of the given data using the given algorithm.
private static void	hashStream(org.bouncycastle.crypto.Digest digest, java.io.InputStream in) Digests the data in the given stream.
static byte[]	sha1(java.lang.Object... data) Produces the SHA-1 hash of the given data.
static byte[]	sha256(java.lang.Object... data) Produces the SHA-256 hash of the given data.
static byte[]	sha3(int bitLength, java.lang.Object... data) Produces the SHA-3 hash of the given data.
static byte[]	sha512(java.lang.Object... data) Produces the SHA-512 hash of the given data.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HashUtil

private HashUtil()

Private constructor of utility class.

Method Detail

hash

public static byte[] hash(org.bouncycastle.crypto.Digest digest,
                          java.lang.Object... data)
                   throws CryptoException,
                          StreamException

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);
 

Parameters:

digest - Hash algorithm.

data - Data to hash. Supported types are byte[], CharSequence ,InputStream, and 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.

Returns:

Byte array of length Digest.getDigestSize() containing hash output.

Throws:

CryptoException - on hash computation errors.

StreamException - on stream IO errors.

hash

public static byte[] hash(org.bouncycastle.crypto.Digest digest,
                          int iterations,
                          java.lang.Object... data)
                   throws CryptoException,
                          StreamException

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);
 

Parameters:

digest - Hash algorithm.

iterations - Number of hash rounds. Must be positive value.

data - Data to hash. Supported types are byte[], CharSequence ,InputStream, and 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.

Returns:

Byte array of length Digest.getDigestSize() containing hash output.

Throws:

CryptoException - on hash computation errors.

StreamException - on stream IO errors.

compareHash

public static boolean compareHash(org.bouncycastle.crypto.Digest digest,
                                  byte[] hash,
                                  int iterations,
                                  java.lang.Object... data)
                           throws CryptoException,
                                  StreamException

Determines whether the hash of the given input equals a known value.

Parameters:

digest - Hash algorithm.

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.

iterations - Number of hash rounds.

data - Data to hash.

Returns:

True if the hash of the data under the given digest is equal to the hash, false otherwise.

Throws:

CryptoException - on hash computation errors.

StreamException - on stream IO errors.

compareHash

public static boolean compareHash(org.bouncycastle.crypto.Digest digest,
                                  SaltedHash hash,
                                  int iterations,
                                  boolean saltAfterData,
                                  java.lang.Object... data)
                           throws CryptoException,
                                  StreamException

Determines whether the salted hash of the given input equals a known hash value.

Parameters:

digest - Hash algorithm.

hash - Salted hash data.

iterations - Number of hash rounds.

saltAfterData - True to apply salt after data, false to apply salt before data.

data - Data to hash, which should NOT include the salt value.

Returns:

True if the hash of the data under the given digest is equal to the hash, false otherwise.

Throws:

CryptoException - on hash computation errors.

StreamException - on stream IO errors.

sha1

public static byte[] sha1(java.lang.Object... data)

Produces the SHA-1 hash of the given data.

Parameters:

data - Data to hash. See hash(Digest, Object...) for supported inputs.

Returns:

20-byte array containing hash output.

See Also:

hash(Digest, Object...)

sha256

public static byte[] sha256(java.lang.Object... data)

Produces the SHA-256 hash of the given data.

Parameters:

data - Data to hash. See hash(Digest, Object...) for supported inputs.

Returns:

32-byte array containing hash output.

See Also:

hash(Digest, Object...)

sha512

public static byte[] sha512(java.lang.Object... data)

Produces the SHA-512 hash of the given data.

Parameters:

data - Data to hash. See hash(Digest, Object...) for supported inputs.

Returns:

64-byte array containing hash output.

See Also:

hash(Digest, Object...)

sha3

public static byte[] sha3(int bitLength,
                          java.lang.Object... data)

Produces the SHA-3 hash of the given data.

Parameters:

bitLength - One of the supported SHA-3 output bit lengths: 224, 256, 384, or 512.

data - Data to hash. See hash(Digest, Object...) for supported inputs.

Returns:

Byte array of size bitLength containing hash output.

See Also:

hash(Digest, Object...)

hashStream

private static void hashStream(org.bouncycastle.crypto.Digest digest,
                               java.io.InputStream in)

Digests the data in the given stream. Note this method does not finalize the digest process by calling Digest.doFinal(byte[], int).

Parameters:

digest - Digest algorithm.

in - Input stream containing data to hash.