java.lang.Object
- org.bouncycastle.pqc.math.linearalgebra.GoppaCode

```
public final class GoppaCode
extends java.lang.Object
```
This class describes decoding operations of an irreducible binary Goppa code. A check matrix H of the Goppa code and an irreducible Goppa polynomial are used the operations are worked over a finite field GF(2^m)

See Also:

GF2mField, PolynomialGF2mSmallM

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`GoppaCode.MaMaPe`	This class is a container for two instances of `GF2Matrix` and one instance of `Permutation`.
`static class`	`GoppaCode.MatrixSet`	This class is a container for an instance of `GF2Matrix` and one int[].

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static GoppaCode.MaMaPe`	`computeSystematicForm(GF2Matrix h, java.security.SecureRandom sr)`	Given a check matrix `H`, compute matrices `S`, `M`, and a random permutation `P` such that `SHP = (Id\|M)`.
`static GF2Matrix`	`createCanonicalCheckMatrix(GF2mField field, PolynomialGF2mSmallM gp)`	Construct the check matrix of a Goppa code in canonical form from the irreducible Goppa polynomial over the finite field `GF(2^m)`.
`static GF2Vector`	`syndromeDecode(GF2Vector syndVec, GF2mField field, PolynomialGF2mSmallM gp, PolynomialGF2mSmallM[] sqRootMatrix)`	Find an error vector `e` over `GF(2)` from an input syndrome `s` over `GF(2^m)`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - createCanonicalCheckMatrix
```
public static GF2Matrix createCanonicalCheckMatrix(GF2mField field,
                                                   PolynomialGF2mSmallM gp)
```
    Construct the check matrix of a Goppa code in canonical form from the irreducible Goppa polynomial over the finite field GF(2^m).
    
    Parameters:
    
    field - the finite field
    
    gp - the irreducible Goppa polynomial
  - computeSystematicForm
```
public static GoppaCode.MaMaPe computeSystematicForm(GF2Matrix h,
                                                     java.security.SecureRandom sr)
```
    Given a check matrix H, compute matrices S, M, and a random permutation P such that S*H*P = (Id|M). Return S^-1, M, and P as GoppaCode.MaMaPe. The matrix (Id | M) is called the systematic form of H.
    
    Parameters:
    
    h - the check matrix
    
    sr - a source of randomness
    
    Returns:
    
    the tuple (S^-1, M, P)
  - syndromeDecode
```
public static GF2Vector syndromeDecode(GF2Vector syndVec,
                                       GF2mField field,
                                       PolynomialGF2mSmallM gp,
                                       PolynomialGF2mSmallM[] sqRootMatrix)
```
    Find an error vector e over GF(2) from an input syndrome s over GF(2^m).
    
    Parameters:
    
    syndVec - the syndrome
    
    field - the finite field
    
    gp - the irreducible Goppa polynomial
    
    sqRootMatrix - the matrix for computing square roots in (GF(2^m))^t
    
    Returns:
    
    the error vector

Class GoppaCode

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

createCanonicalCheckMatrix

computeSystematicForm

syndromeDecode