Package com.mku.salmon.integrity

Class Integrity

java.lang.Object

com.mku.salmon.integrity.Integrity

public class Integrity
extends java.lang.Object

Provide operations for calculating, storing, and verifying data integrity. This class operates on chunks of byte arrays calculating hashes for each one.

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_CHUNK_SIZE	Default chunk size for integrity.
static int	MAX_CHUNK_SIZE	Maximum chunk size for data integrity.

Constructor Summary

Constructors

Constructor	Description
Integrity(boolean integrity, byte[] key, int chunkSize, IHashProvider provider, int hashSize)	Instantiate an object to be used for applying and verifying hash signatures for each of the data chunks.

Method Summary

Modifier and Type	Method	Description
static byte[]	calculateHash(IHashProvider provider, byte[] buffer, int offset, int count, byte[] key, byte[] includeData)	Calculate hash of the data provided.
byte[][]	generateHashes(byte[] buffer, byte[] includeData)	Generate a hash signatures for each data chunk.
int	getChunkSize()	Get the chunk size.
long	getHashDataLength(long count, int hashOffset)	Return the number of bytes that all hash signatures occupy for each chunk size
byte[][]	getHashes(byte[] buffer)	Get the hashes for each data chunk.
byte[]	getKey()	Get the hash key.
static long	getTotalHashDataLength(EncryptionMode mode, long length, int chunkSize, int hashOffset, int hashLength)	Get the total number of bytes for all hash signatures for data of a specific length.
boolean	useIntegrity()	Get the integrity enabled option.
void	verifyHashes(byte[][] hashes, byte[] buffer, byte[] includeHeaderData)	Verify the buffer chunks against the hash signatures.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_CHUNK_SIZE

public static final int MAX_CHUNK_SIZE

Maximum chunk size for data integrity.

See Also:

Constant Field Values

DEFAULT_CHUNK_SIZE

public static final int DEFAULT_CHUNK_SIZE

Default chunk size for integrity.

See Also:

Constant Field Values

Constructor Detail

Integrity

public Integrity(boolean integrity,
                 byte[] key,
                 int chunkSize,
                 IHashProvider provider,
                 int hashSize)

Instantiate an object to be used for applying and verifying hash signatures for each of the data chunks.

Parameters:

integrity - True to enable integrity check.

key - The key to use for hashing.

chunkSize - The chunk size. Use 0 to use default. Use a positive number to specify integrity chunks.

provider - Hash implementation provider.

hashSize - The hash size.

Throws:

IntegrityException - Thrown if the data are corrupt or tampered with.

SecurityException - Thrown when security has failed

Method Detail

calculateHash

public static byte[] calculateHash(IHashProvider provider,
                                   byte[] buffer,
                                   int offset,
                                   int count,
                                   byte[] key,
                                   byte[] includeData)

Calculate hash of the data provided.

Parameters:

provider - Hash implementation provider.

buffer - Data to calculate the hash.

offset - Offset of the buffer that the hashing calculation will start from

count - Length of the buffer that will be used to calculate the hash.

key - Key that will be used

includeData - Additional data to be included in the calculation.

Returns:

The hash.

Throws:

IntegrityException - Thrown if the data are corrupt or tampered with.

getTotalHashDataLength

public static long getTotalHashDataLength(EncryptionMode mode,
                                          long length,
                                          int chunkSize,
                                          int hashOffset,
                                          int hashLength)

Get the total number of bytes for all hash signatures for data of a specific length.

Parameters:

mode - The encryption mode

length - The length of the data.

chunkSize - The byte size of the stream chunk that will be used to calculate the hash. The length should be fixed value except for the last chunk which might be lesser since we don't use padding

hashOffset - The hash key length that will be used as an offset.

hashLength - The hash length.

Returns:

The total hash data length

getHashDataLength

public long getHashDataLength(long count,
                              int hashOffset)

Return the number of bytes that all hash signatures occupy for each chunk size

Parameters:

count - Actual length of the real data int the base stream including header and hash signatures.

hashOffset - The hash key length

Returns:

The number of bytes all hash signatures occupy

getChunkSize

public int getChunkSize()

Get the chunk size.

Returns:

The chunk size.

getKey

public byte[] getKey()

Get the hash key.

Returns:

The hash key.

useIntegrity

public boolean useIntegrity()

Get the integrity enabled option.

Returns:

True if integrity is enabled.

generateHashes

public byte[][] generateHashes(byte[] buffer,
                               byte[] includeData)

Generate a hash signatures for each data chunk.

Parameters:

buffer - The buffer containing the data chunks.

includeData - Additional data to be included in the hash generation.

Returns:

The hash signatures.

Throws:

IntegrityException - Thrown if the data are corrupt or tampered with.

getHashes

public byte[][] getHashes(byte[] buffer)

Get the hashes for each data chunk.

Parameters:

buffer - The buffer that contains the data chunks.

Returns:

The hash signatures.

verifyHashes

public void verifyHashes(byte[][] hashes,
                         byte[] buffer,
                         byte[] includeHeaderData)

Verify the buffer chunks against the hash signatures.

Parameters:

hashes - The hashes to verify.

buffer - The buffer that contains the chunks to verify the hashes.

includeHeaderData - The header data to include

Throws:

IntegrityException - Thrown if the data are corrupt or tampered with.