org.linguafranca.pwdb.hashedblock

Class HmacBlockInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

org.linguafranca.pwdb.hashedblock.HmacBlockInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class HmacBlockInputStream
extends FilterInputStream

Takes an underlying stream formatted as HMAC Hashed Blocks and provides the content of the blocks as a stream.

An HMac block consists of

1. a 32 byte HMac checksum
2. a 4 byte block size
3. {blockSize} bytes of data

The Class is initialised with an initial key digest. For each block this key is transformed using the (implied, starting from 0) block number and used as key for the block verification process. That process consists of digesting the block number, its length and its content.

KeePass streams are Little Endian.

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
HmacBlockInputStream(byte[] key, InputStream inputStream) Create a (big endian) HMac Block input stream
HmacBlockInputStream(byte[] key, InputStream inputStream, boolean littleEndian) Create an HMac Block input stream

Method Summary

Modifier and Type	Method and Description
int	read()
int	read(@NotNull byte[] b)
int	read(@NotNull byte[] b, int off, int len)

Methods inherited from class java.io.FilterInputStream

available, close, mark, markSupported, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

HmacBlockInputStream

public HmacBlockInputStream(byte[] key,
                            InputStream inputStream)
                     throws IOException

Create a (big endian) HMac Block input stream

Parameters:

key - the key digest

inputStream - the stream to process

Throws:

IOException - when something horrid happens

HmacBlockInputStream

public HmacBlockInputStream(byte[] key,
                            InputStream inputStream,
                            boolean littleEndian)
                     throws IOException

Create an HMac Block input stream

Parameters:

key - the key digest

inputStream - the stream to process

littleEndian - true if the stream is little endian

Throws:

IOException - when something horrid happens

Method Detail

read

public int read(@NotNull
                @NotNull byte[] b)
         throws IOException

Overrides:

read in class FilterInputStream

Throws:

IOException

read

public int read(@NotNull
                @NotNull byte[] b,
                int off,
                int len)
         throws IOException

Overrides:

read in class FilterInputStream

Throws:

IOException

read

public int read()
         throws IOException

Overrides:

read in class FilterInputStream

Throws:

IOException