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org.bouncycastle.pqc.crypto.rainbow

pack-priv Class GF2Field

extends Object
Class Inheritance
Imports
org.bouncycastle.util.Pack
This class provides the basic operations like addition, multiplication and finding the multiplicative inverse of an element in GF2^8.

GF2^8 is implemented using the tower representation: gf4 := gf2[x]/x^2+x+1 gf16 := gf4[y]/y^2+y+x gf256 := gf16[X]/X^2+X+xy

Field Summary

Modifier and TypeField and Description
pack-priv static final byte[]
gfInvTable

pack-priv static final byte[][]
gfMulTable

public static final int
MASK

Constructor Summary

AccessConstructor and Description
pack-priv
GF2Field()

Method Summary

Modifier and TypeMethod and Description
public static short

Returns:

the sum of the two elements a and b in GF2^8
addElem(short
the first element that is to be added
a, short
the second element that should be added
b)

This function calculates the sum of two elements as an operation in GF2^8

public static long
addElem_64(long a, long b)

private static short
gf16Mul(short a, short b)

private static short
gf16Mul8(short a)

private static long
gf16Mul8_64(long p)

private static long
gf16Mul_64(long p, long q)

private static short
gf16Squ(short a)

private static long
gf16Squ_64(long p)

private static short
gf256Inv(short a)

private static long
gf256Inv_64(long p)

private static short
gf256Mul(short a, short b)

private static long
gf256Mul_64(long p, long q)

private static short
gf256Squ(short a)

private static long
gf256Squ_64(long p)

private static short
gf4Mul(short a, short b)

private static short
gf4Mul2(short a)

private static long
gf4Mul2_64(long p)

private static short
gf4Mul3(short a)

private static long
gf4Mul_64(long p, long q)

private static short
gf4Squ(short a)

private static long
gf4Squ_64(long p)

public static short

Returns:

the multiplicative inverse of the given element, in case it exists or 0, otherwise
invElem(short
the element which multiplicative inverse is to be computed
a)

This function computes the multiplicative inverse of a given element in GF2^8 The 0 has no multiplicative inverse and in this case 0 is returned.

public static long
invElem_64(long a)

public static short

Returns:

the product of the two input elements in GF2^8.
multElem(short
the first element to be multiplied.
a, short
the second element to be multiplied.
b)

This function multiplies two elements in GF2^8.

public static long
multElem_64(long a, long b)

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

gfInvTableback to summary
pack-priv static final byte[] gfInvTable
gfMulTableback to summary
pack-priv static final byte[][] gfMulTable
MASKback to summary
public static final int MASK

Constructor Detail

GF2Fieldback to summary
pack-priv GF2Field()

Method Detail

addElemback to summary
public static short addElem(short a, short b)

This function calculates the sum of two elements as an operation in GF2^8

Parameters
a:short

the first element that is to be added

b:short

the second element that should be added

Returns:short

the sum of the two elements a and b in GF2^8

addElem_64back to summary
public static long addElem_64(long a, long b)
gf16Mulback to summary
private static short gf16Mul(short a, short b)
gf16Mul8back to summary
private static short gf16Mul8(short a)
gf16Mul8_64back to summary
private static long gf16Mul8_64(long p)
gf16Mul_64back to summary
private static long gf16Mul_64(long p, long q)
gf16Squback to summary
private static short gf16Squ(short a)
gf16Squ_64back to summary
private static long gf16Squ_64(long p)
gf256Invback to summary
private static short gf256Inv(short a)
gf256Inv_64back to summary
private static long gf256Inv_64(long p)
gf256Mulback to summary
private static short gf256Mul(short a, short b)
gf256Mul_64back to summary
private static long gf256Mul_64(long p, long q)
gf256Squback to summary
private static short gf256Squ(short a)
gf256Squ_64back to summary
private static long gf256Squ_64(long p)
gf4Mulback to summary
private static short gf4Mul(short a, short b)
gf4Mul2back to summary
private static short gf4Mul2(short a)
gf4Mul2_64back to summary
private static long gf4Mul2_64(long p)
gf4Mul3back to summary
private static short gf4Mul3(short a)
gf4Mul_64back to summary
private static long gf4Mul_64(long p, long q)
gf4Squback to summary
private static short gf4Squ(short a)
gf4Squ_64back to summary
private static long gf4Squ_64(long p)
invElemback to summary
public static short invElem(short a)

This function computes the multiplicative inverse of a given element in GF2^8 The 0 has no multiplicative inverse and in this case 0 is returned.

Parameters
a:short

the element which multiplicative inverse is to be computed

Returns:short

the multiplicative inverse of the given element, in case it exists or 0, otherwise

invElem_64back to summary
public static long invElem_64(long a)
multElemback to summary
public static short multElem(short a, short b)

This function multiplies two elements in GF2^8. If one of the two elements is 0, 0 is returned.

Parameters
a:short

the first element to be multiplied.

b:short

the second element to be multiplied.

Returns:short

the product of the two input elements in GF2^8.

multElem_64back to summary
public static long multElem_64(long a, long b)