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Spongy Castle is a package-rename (org.bouncycastle.* to org.spongycastle.*) of Bouncy Castle
intended for the Android platform. Android unfortunately ships with a stripped-down version of
Bouncy Castle, which prevents easy upgrades - Spongy Castle overcomes this and provides a full,
up-to-date version of the Bouncy Castle cryptographic libs.
package org.spongycastle.pqc.jcajce.provider.mceliece;
import java.io.IOException;
import java.security.PrivateKey;
import org.spongycastle.asn1.ASN1ObjectIdentifier;
import org.spongycastle.asn1.ASN1Primitive;
import org.spongycastle.asn1.DERNull;
import org.spongycastle.asn1.pkcs.PrivateKeyInfo;
import org.spongycastle.asn1.x509.AlgorithmIdentifier;
import org.spongycastle.crypto.CipherParameters;
import org.spongycastle.pqc.asn1.McEliecePrivateKey;
import org.spongycastle.pqc.crypto.mceliece.McElieceKeyPairGenerator;
import org.spongycastle.pqc.crypto.mceliece.McElieceParameters;
import org.spongycastle.pqc.crypto.mceliece.McEliecePrivateKeyParameters;
import org.spongycastle.pqc.jcajce.spec.McEliecePrivateKeySpec;
import org.spongycastle.pqc.math.linearalgebra.GF2Matrix;
import org.spongycastle.pqc.math.linearalgebra.GF2mField;
import org.spongycastle.pqc.math.linearalgebra.Permutation;
import org.spongycastle.pqc.math.linearalgebra.PolynomialGF2mSmallM;
/**
* This class implements a McEliece private key and is usually instantiated by
* the {@link McElieceKeyPairGenerator} or {@link McElieceKeyFactorySpi}.
*/
public class BCMcEliecePrivateKey
implements CipherParameters, PrivateKey
{
/**
*
*/
private static final long serialVersionUID = 1L;
// the OID of the algorithm
private String oid;
// the length of the code
private int n;
// the dimension of the code, where k >= n - mt
private int k;
// the underlying finite field
private GF2mField field;
// the irreducible Goppa polynomial
private PolynomialGF2mSmallM goppaPoly;
// the matrix S^-1
private GF2Matrix sInv;
// the permutation P1 used to generate the systematic check matrix
private Permutation p1;
// the permutation P2 used to compute the public generator matrix
private Permutation p2;
// the canonical check matrix of the code
private GF2Matrix h;
// the matrix used to compute square roots in (GF(2^m))^t
private PolynomialGF2mSmallM[] qInv;
private McElieceParameters mcElieceParams;
/**
* Constructor (used by the {@link McElieceKeyPairGenerator}).
*
* @param oid
* @param n the length of the code
* @param k the dimension of the code
* @param field the field polynomial defining the finite field
* GF(2m)
* @param goppaPoly the irreducible Goppa polynomial
* @param sInv the matrix S-1
* @param p1 the permutation used to generate the systematic check
* matrix
* @param p2 the permutation used to compute the public generator
* matrix
* @param h the canonical check matrix
* @param qInv the matrix used to compute square roots in
* (GF(2m))t
*/
public BCMcEliecePrivateKey(String oid, int n, int k, GF2mField field,
PolynomialGF2mSmallM goppaPoly, GF2Matrix sInv, Permutation p1,
Permutation p2, GF2Matrix h, PolynomialGF2mSmallM[] qInv)
{
this.oid = oid;
this.n = n;
this.k = k;
this.field = field;
this.goppaPoly = goppaPoly;
this.sInv = sInv;
this.p1 = p1;
this.p2 = p2;
this.h = h;
this.qInv = qInv;
}
/**
* Constructor (used by the {@link McElieceKeyFactorySpi}).
*
* @param keySpec a {@link McEliecePrivateKeySpec}
*/
public BCMcEliecePrivateKey(McEliecePrivateKeySpec keySpec)
{
this(keySpec.getOIDString(), keySpec.getN(), keySpec.getK(), keySpec.getField(), keySpec
.getGoppaPoly(), keySpec.getSInv(), keySpec.getP1(), keySpec
.getP2(), keySpec.getH(), keySpec.getQInv());
}
public BCMcEliecePrivateKey(McEliecePrivateKeyParameters params)
{
this(params.getOIDString(), params.getN(), params.getK(), params.getField(), params.getGoppaPoly(),
params.getSInv(), params.getP1(), params.getP2(), params.getH(), params.getQInv());
this.mcElieceParams = params.getParameters();
}
/**
* Return the name of the algorithm.
*
* @return "McEliece"
*/
public String getAlgorithm()
{
return "McEliece";
}
/**
* @return the length of the code
*/
public int getN()
{
return n;
}
/**
* @return the dimension of the code
*/
public int getK()
{
return k;
}
/**
* @return the finite field
*/
public GF2mField getField()
{
return field;
}
/**
* @return the irreducible Goppa polynomial
*/
public PolynomialGF2mSmallM getGoppaPoly()
{
return goppaPoly;
}
/**
* @return the k x k random binary non-singular matrix S
*/
public GF2Matrix getSInv()
{
return sInv;
}
/**
* @return the permutation used to generate the systematic check matrix
*/
public Permutation getP1()
{
return p1;
}
/**
* @return the permutation used to compute the public generator matrix
*/
public Permutation getP2()
{
return p2;
}
/**
* @return the canonical check matrix
*/
public GF2Matrix getH()
{
return h;
}
/**
* @return the matrix for computing square roots in (GF(2^m))^t
*/
public PolynomialGF2mSmallM[] getQInv()
{
return qInv;
}
/**
* @return the OID of the algorithm
*/
public String getOIDString()
{
return oid;
}
/**
* @return a human readable form of the key
*/
public String toString()
{
String result = " length of the code : " + n + "\n";
result += " dimension of the code : " + k + "\n";
result += " irreducible Goppa polynomial: " + goppaPoly + "\n";
result += " (k x k)-matrix S^-1 : " + sInv + "\n";
result += " permutation P1 : " + p1 + "\n";
result += " permutation P2 : " + p2;
return result;
}
/**
* Compare this key with another object.
*
* @param other the other object
* @return the result of the comparison
*/
public boolean equals(Object other)
{
if (!(other instanceof BCMcEliecePrivateKey))
{
return false;
}
BCMcEliecePrivateKey otherKey = (BCMcEliecePrivateKey)other;
return (n == otherKey.n) && (k == otherKey.k)
&& field.equals(otherKey.field)
&& goppaPoly.equals(otherKey.goppaPoly)
&& sInv.equals(otherKey.sInv) && p1.equals(otherKey.p1)
&& p2.equals(otherKey.p2) && h.equals(otherKey.h);
}
/**
* @return the hash code of this key
*/
public int hashCode()
{
return k + n + field.hashCode() + goppaPoly.hashCode()
+ sInv.hashCode() + p1.hashCode() + p2.hashCode()
+ h.hashCode();
}
/**
* @return the OID to encode in the SubjectPublicKeyInfo structure
*/
protected ASN1ObjectIdentifier getOID()
{
return new ASN1ObjectIdentifier(McElieceKeyFactorySpi.OID);
}
/**
* @return the algorithm parameters to encode in the SubjectPublicKeyInfo
* structure
*/
protected ASN1Primitive getAlgParams()
{
return null; // FIXME: needed at all?
}
/**
* Return the key data to encode in the SubjectPublicKeyInfo structure.
*
* The ASN.1 definition of the key structure is
*
*
* McEliecePrivateKey ::= SEQUENCE {
* n INTEGER -- length of the code
* k INTEGER -- dimension of the code
* fieldPoly OCTET STRING -- field polynomial defining GF(2ˆm)
* goppaPoly OCTET STRING -- irreducible Goppa polynomial
* sInv OCTET STRING -- matrix Sˆ-1
* p1 OCTET STRING -- permutation P1
* p2 OCTET STRING -- permutation P2
* h OCTET STRING -- canonical check matrix
* qInv SEQUENCE OF OCTET STRING -- matrix used to compute square roots
* }
*
*
* @return the key data to encode in the SubjectPublicKeyInfo structure
*/
public byte[] getEncoded()
{
McEliecePrivateKey privateKey = new McEliecePrivateKey(new ASN1ObjectIdentifier(oid), n, k, field, goppaPoly, sInv, p1, p2, h, qInv);
PrivateKeyInfo pki;
try
{
AlgorithmIdentifier algorithmIdentifier = new AlgorithmIdentifier(this.getOID(), DERNull.INSTANCE);
pki = new PrivateKeyInfo(algorithmIdentifier, privateKey);
}
catch (IOException e)
{
e.printStackTrace();
return null;
}
try
{
byte[] encoded = pki.getEncoded();
return encoded;
}
catch (IOException e)
{
e.printStackTrace();
return null;
}
}
public String getFormat()
{
// TODO Auto-generated method stub
return null;
}
public McElieceParameters getMcElieceParameters()
{
return mcElieceParams;
}
}
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