edu.harvard.deas.hyperenc.vsat
Class FileRandomSource

java.lang.Object
  edu.harvard.deas.hyperenc.vsat.TrueRandomSource
      edu.harvard.deas.hyperenc.vsat.FileRandomSource

public class FileRandomSource
extends TrueRandomSource

FileRandomSource (FRS) traverses the file system collecting random data. Then, it encrypts, compresses and then xor's the resulting pages to produce a final page to hand to the PSN

Field Summary

static int

NUM_PAGES Number of random pages to combine into the final random page

Fields inherited from class edu.harvard.deas.hyperenc.vsat.TrueRandomSource

DATA_LENGTH

Constructor Summary

FileRandomSource()
Simple constructor to initialize components

Method Summary

byte[]	compressPage(byte[] page) Returns the result of compressing the given page or null if we hit problems XXX Remove the temporary hack of zero-padding
byte[]	encryptPage(byte[] page) Returns the result of encrypting the given page using a random key with Triple DES, or null if it encounters an error
boolean	genFileData(File startNode) Function to gather random data from the file system Randomly selects a target depth and then calls fileSearch to do the actual descent
byte[]	genRandomness() Pieces everything together: Gathers file data and then encrypts, compresses and xor's pages to return a page of random data Returns null if it encounters an error
byte[]	xor(byte[] page1, byte[] page2) Computes the byte-wise xor of page1 and page2

Methods inherited from class java.lang.Object

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

Field Detail

NUM_PAGES

public static final int NUM_PAGES

Number of random pages to combine into the final random page

See Also:

Constant Field Values

Constructor Detail

FileRandomSource

public FileRandomSource()

Simple constructor to initialize components

Method Detail

genRandomness

public byte[] genRandomness()

Pieces everything together: Gathers file data and then encrypts, compresses and xor's pages to return a page of random data Returns null if it encounters an error

Specified by:

genRandomness in class TrueRandomSource

xor

public byte[] xor(byte[] page1,
                  byte[] page2)

Computes the byte-wise xor of page1 and page2

encryptPage

public byte[] encryptPage(byte[] page)

Returns the result of encrypting the given page using a random key with Triple DES, or null if it encounters an error

Parameters:

page - The array of bytes to be encrypted

compressPage

public byte[] compressPage(byte[] page)

Returns the result of compressing the given page or null if we hit problems XXX Remove the temporary hack of zero-padding

Parameters:

page - An array of FILE_READ_SIZE bytes to be compressed

Returns:

The compressed data, with zeros appended to make the length FILE_READ_SIZE bytes

genFileData

public boolean genFileData(File startNode)

Function to gather random data from the file system Randomly selects a target depth and then calls fileSearch to do the actual descent