software.engine
Class RowPermutation

java.lang.Object
  software.engine.RowPermutation

public class RowPermutation
extends java.lang.Object

Computes the row permutations using the following algorithm
Let M be a byte array of length 16. On the first possitions M will have tableInstance. On the following possitions M will have columnName Compute a secret key SK = Dmk1(C xor Emk2(C xor Emk1(M))) AES128 ECB NoPadding Let MM be a byte array with the string representation of the serial numbers Using the secret key SK, encrypt MM using AES128 ECB PKCS#5Padding - sort the cryptograms to generate the permutation

Field Summary

static byte[]	D1CONSTANT
static byte[]	D1D5CONSTANT

Constructor Summary

RowPermutation()

Method Summary

static int[]	permuteD1(javax.crypto.spec.SecretKeySpec mk1, javax.crypto.spec.SecretKeySpec mk2, byte[] c, byte tableInstance, int startSerial, int endSerial, byte partitionId) Gets the permutation mapping D to P.
static int[]	permuteD1D5(javax.crypto.spec.SecretKeySpec mk1, javax.crypto.spec.SecretKeySpec mk2, byte[] c, int startSerial, int endSerial, byte partitionId) Gets the permutation mapping D1 to D5.
static int[]	permuteD5(int[] master, int[] d1) Deterministically computes the mapping between D and R, based on the mapping between P and D (D1) and D1 to D5.

Methods inherited from class java.lang.Object

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

Field Detail

D1D5CONSTANT

public static byte[] D1D5CONSTANT

D1CONSTANT

public static byte[] D1CONSTANT

Constructor Detail

RowPermutation

public RowPermutation()

Method Detail

permuteD1D5

public static int[] permuteD1D5(javax.crypto.spec.SecretKeySpec mk1,
                                javax.crypto.spec.SecretKeySpec mk2,
                                byte[] c,
                                int startSerial,
                                int endSerial,
                                byte partitionId)
                         throws java.lang.Exception

Gets the permutation mapping D1 to D5. This maping is the same for all the instances of the D tables (because one P has to be mapped to one R)

Parameters:

mk1 - - master key 1

mk2 - - master key 2

c - - public constant

startSerial - - the first serial numbered considered (ussualy 0)

endSerial - - the last serial number considered (including) (ussualy the number of ballots)

partitionId -

Returns:

a permutation of length endSerial-startSerial+1

Throws:

java.lang.Exception - - no Exception is caugth and no Exception is Explicitly thrown

permuteD1

public static int[] permuteD1(javax.crypto.spec.SecretKeySpec mk1,
                              javax.crypto.spec.SecretKeySpec mk2,
                              byte[] c,
                              byte tableInstance,
                              int startSerial,
                              int endSerial,
                              byte partitionId)
                       throws java.lang.Exception

Gets the permutation mapping D to P. This permutation is different for every instance of the D table

Parameters:

mk1 - - master key 1

mk2 - - master key 2

c - - public constant

tableInstance -

startSerial - - the first serial numbered considered (ussualy 0)

endSerial - - the last serial number considered (including) (ussualy the number of ballots)

partitionId -

Returns:

a permutation of length endSerial-startSerial+1

Throws:

java.lang.Exception - - no Exception is caugth and no Exception is Explicitly thrown

permuteD5

public static int[] permuteD5(int[] master,
                              int[] d1)
                       throws java.lang.Exception

Deterministically computes the mapping between D and R, based on the mapping between P and D (D1) and D1 to D5.

Parameters:

master - the D1D5 permutation

d1 - d1 permutation

Returns:

master[d1]

Throws:

java.lang.Exception - - no Exception is caugth and no Exception is Explicitly thrown