de.flexiprovider.common.math.polynomials
Class ProductFormConvolutionPolynomial

java.lang.Object
  |
  +--de.flexiprovider.common.math.polynomials.ProductFormConvolutionPolynomial

All Implemented Interfaces:

ConvolutionPolynomial

public class ProductFormConvolutionPolynomial

extends java.lang.Object

implements ConvolutionPolynomial

This class represents product form polynomials in Z(X)/(X^N-1), i.e. polynomials of the form f1*f2+f3, where f1, f2, and f3 are sparse binary polynomials.

The fields have package visibility so that they can be accessed by ModQConvolutionPolynomial.

Author:

Martin Döring

See Also:

SparseBinaryConvolutionPolynomial

Field Summary

(package private) SparseBinaryConvolutionPolynomial	f1 The three sparse binary polynomials
(package private) SparseBinaryConvolutionPolynomial	f2 The three sparse binary polynomials
(package private) SparseBinaryConvolutionPolynomial	f3 The three sparse binary polynomials
(package private) int	N The degree of the reduction polynomial

Constructor Summary

ProductFormConvolutionPolynomial(int N, int d1, int d2, int d3, SecureRandom sr)
Construct a random product form polynomial.

ProductFormConvolutionPolynomial(ProductFormConvolutionPolynomial other)
Copy constructor.

ProductFormConvolutionPolynomial(SparseBinaryConvolutionPolynomial f1, SparseBinaryConvolutionPolynomial f2, SparseBinaryConvolutionPolynomial f3)
Construct a product form polynomial out of the three given sparse binary polynomials.

Method Summary

boolean	equals(java.lang.Object other) Compare this polynomial with the given object.
int	hashCode()
static ProductFormConvolutionPolynomial	OS2REP(int N, int q, int d1, int d2, int d3, byte[] encoded) Decode a byte array into a product form polynomial.
byte[]	RE2OSP(int N) Encode this polynomial as a byte array.
java.lang.String	toString()

Methods inherited from class java.lang.Object

, clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

N

int N

The degree of the reduction polynomial

f1

SparseBinaryConvolutionPolynomial f1

The three sparse binary polynomials

f2

SparseBinaryConvolutionPolynomial f2

The three sparse binary polynomials

f3

SparseBinaryConvolutionPolynomial f3

The three sparse binary polynomials

Constructor Detail

ProductFormConvolutionPolynomial

public ProductFormConvolutionPolynomial(int N,
                                        int d1,
                                        int d2,
                                        int d3,
                                        SecureRandom sr)

Construct a random product form polynomial.

Parameters:

N - the degree of the reduction polynomial

d1 - the number of non-zero coefficients of the first sparse binary polynomial

d2 - the number of non-zero coefficients of the second sparse binary polynomial

d3 - the number of non-zero coefficients of the third sparse binary polynomial

sr - the source of randomness used for creating the sparse binary polynomial

ProductFormConvolutionPolynomial

public ProductFormConvolutionPolynomial(SparseBinaryConvolutionPolynomial f1,
                                        SparseBinaryConvolutionPolynomial f2,
                                        SparseBinaryConvolutionPolynomial f3)
                                 throws java.lang.ArithmeticException

Construct a product form polynomial out of the three given sparse binary polynomials.

Parameters:

f1 - the first sparse binary polynomial

f2 - the second sparse binary polynomial

f3 - the third sparse binary polynomial

Throws:

java.lang.ArithmeticException - if the sparse binary polynomials are not elements of the same ring

ProductFormConvolutionPolynomial

public ProductFormConvolutionPolynomial(ProductFormConvolutionPolynomial other)

Copy constructor.

Parameters:

other - another ModQPolynomialProductForm

Method Detail

RE2OSP

public byte[] RE2OSP(int N)
              throws java.lang.ArithmeticException

Encode this polynomial as a byte array.

Parameters:

N - the degree of the reduction polynomial

Returns:

the encoded polynomial

Throws:

java.lang.ArithmeticException - if this polynomial is not a binary element of Z(X)/(X^N-1).

OS2REP

public static ProductFormConvolutionPolynomial OS2REP(int N,
                                                      int q,
                                                      int d1,
                                                      int d2,
                                                      int d3,
                                                      byte[] encoded)
                                               throws java.lang.IllegalArgumentException

Decode a byte array into a product form polynomial.

Parameters:

N - - the degree of the reduction polynomial

q - - the modulus

d1 - - the number of non-zero coefficients of the first sparse binary polynomial

d2 - - the number of non-zero coefficients of the second sparse binary polynomial

d3 - - the number of non-zero coefficients of the third sparse binary polynomial

encoded - - the encoded polynomial

Returns:

the decoded polynomial

Throws:

java.lang.IllegalArgumentException - if the encoded polynomial has wrong length.

equals

public boolean equals(java.lang.Object other)

Compare this polynomial with the given object.

Overrides:

equals in class java.lang.Object

Parameters:

other - the other object

Returns:

the result of the comparison

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

Returns:

the hash code of this polynomial

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

Returns:

a human readable form of this polynomial