Package com.healthmarketscience.jackcess.crypt.impl

Class BaseCryptCodecHandler

java.lang.Object

com.healthmarketscience.jackcess.crypt.impl.BaseCryptCodecHandler

All Implemented Interfaces:

CodecHandler

Direct Known Subclasses:

BaseJetCryptCodecHandler, OfficeCryptCodecHandler

public abstract class BaseCryptCodecHandler
extends Object
implements CodecHandler

Common CodecHandler support.

Author:

Vladimir Berezniker

Field Summary

Fields

Modifier and Type	Field	Description
static boolean	CIPHER_DECRYPT_MODE
static boolean	CIPHER_ENCRYPT_MODE

Method Summary

Modifier and Type	Method	Description
static void	applyHeaderMask(ByteBuffer page, JetFormat format)	Removes the header mask from page 0, or puts it back.
static byte[]	applyPageNumber(byte[] key, int offset, int pageNumber)	Returns a copy of the given key with the bytes of the given pageNumber applied at the given offset using XOR.
static int	bits2bytes(int bits)
static int	createEncodingKey()	Returns a page 0 key of the shape ms access writes.
static BufferedBlockCipher	decryptInit(BufferedBlockCipher cipher, CipherParameters params)	Inits the given cipher for decryption with the given params.
static BufferedBlockCipher	encryptInit(BufferedBlockCipher cipher, CipherParameters params)	Inits the given cipher for encryption with the given params.
static byte[]	fill(byte[] bytes, int value)	Fills the given array with the given value and returns it.
static byte[]	fixToLength(byte[] bytes, int len)
static byte[]	fixToLength(byte[] bytes, int len, int padByte)
static byte[]	hash(Digest digest, byte[] bytes)	Hashes the given bytes using the given digest and returns the result.
static byte[]	hash(Digest digest, byte[] bytes1, byte[] bytes2)	Hashes the given bytes1 and bytes2 using the given digest and returns the result.
static byte[]	hash(Digest digest, byte[] bytes1, byte[] bytes2, int resultLen)	Hashes the given bytes1 and bytes2 using the given digest and returns the hash fixed to the given length.
static byte[]	hash(Digest digest, byte[] bytes, int resultLen)	Hashes the given bytes using the given digest and returns the hash fixed to the given length.
static byte[]	iterateHash(Digest digest, byte[] baseHash, int iterations)	Hashes the given hash with its own iteration number, the given number of times.
static byte[]	processBytesFully(BufferedBlockCipher cipher, byte[] inArray)	Runs the given block cipher over the given bytes into a new byte[].
String	toString()
static ByteBuffer	wrap(byte[] bytes)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.healthmarketscience.jackcess.impl.CodecHandler

canDecodeInline, canEncodePartialPage, decodePage, encodePage

Field Detail

CIPHER_DECRYPT_MODE

public static final boolean CIPHER_DECRYPT_MODE

See Also:

Constant Field Values

CIPHER_ENCRYPT_MODE

public static final boolean CIPHER_ENCRYPT_MODE

See Also:

Constant Field Values

Method Detail

toString

public String toString()

Overrides:

toString in class Object

decryptInit

public static BufferedBlockCipher decryptInit(BufferedBlockCipher cipher,
                                              CipherParameters params)

Inits the given cipher for decryption with the given params.

encryptInit

public static BufferedBlockCipher encryptInit(BufferedBlockCipher cipher,
                                              CipherParameters params)

Inits the given cipher for encryption with the given params.

processBytesFully

public static byte[] processBytesFully(BufferedBlockCipher cipher,
                                       byte[] inArray)

Runs the given block cipher over the given bytes into a new byte[]. The cipher carries the direction it was initialized for, so this both encrypts and decrypts.

applyPageNumber

public static byte[] applyPageNumber(byte[] key,
                                     int offset,
                                     int pageNumber)

Returns a copy of the given key with the bytes of the given pageNumber applied at the given offset using XOR.

hash

public static byte[] hash(Digest digest,
                          byte[] bytes)

Hashes the given bytes using the given digest and returns the result.

hash

public static byte[] hash(Digest digest,
                          byte[] bytes1,
                          byte[] bytes2)

Hashes the given bytes1 and bytes2 using the given digest and returns the result.

hash

public static byte[] hash(Digest digest,
                          byte[] bytes,
                          int resultLen)

Hashes the given bytes using the given digest and returns the hash fixed to the given length.

hash

public static byte[] hash(Digest digest,
                          byte[] bytes1,
                          byte[] bytes2,
                          int resultLen)

Hashes the given bytes1 and bytes2 using the given digest and returns the hash fixed to the given length.

iterateHash

public static byte[] iterateHash(Digest digest,
                                 byte[] baseHash,
                                 int iterations)

Hashes the given hash with its own iteration number, the given number of times. This is the work a spin count asks for.

fixToLength

public static byte[] fixToLength(byte[] bytes,
                                 int len)

Returns:

a byte array of the given length, truncating or padding the given byte array as necessary.

fixToLength

public static byte[] fixToLength(byte[] bytes,
                                 int len,
                                 int padByte)

Returns:

a byte array of the given length, truncating or padding the given byte array as necessary using the given padByte.

wrap

public static ByteBuffer wrap(byte[] bytes)

Returns:

a new ByteBuffer wrapping the given bytes with the appropriate byte order

applyHeaderMask

public static void applyHeaderMask(ByteBuffer page,
                                   JetFormat format)

Removes the header mask from page 0, or puts it back. The mask is xor, so the two are one operation.

createEncodingKey

public static int createEncodingKey()

Returns a page 0 key of the shape ms access writes. Ms access uses the windows tick count with 0xa0a00000 set, which makes the high bytes track how long the machine had been running. A random value with the same bits set is the same shape without being guessable, and nothing on the read path compares the key against anything but zero.

bits2bytes

public static int bits2bytes(int bits)

Returns:

the number of whole bytes the given number of bits holds

fill

public static byte[] fill(byte[] bytes,
                          int value)

Fills the given array with the given value and returns it.