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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8 with debug enabled.
package org.bouncycastle.asn1.x9;
import java.math.BigInteger;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERSequence;
/**
* ASN.1 def for Elliptic-Curve Field ID structure. See
* X9.62, for further details.
*/
public class X9FieldID
extends ASN1Object
implements X9ObjectIdentifiers
{
private ASN1ObjectIdentifier id;
private ASN1Primitive parameters;
/**
* Constructor for elliptic curves over prime fields
* F2
.
* @param primeP The prime p
defining the prime field.
*/
public X9FieldID(BigInteger primeP)
{
this.id = prime_field;
this.parameters = new ASN1Integer(primeP);
}
/**
* Constructor for elliptic curves over binary fields
* F2m
.
* @param m The exponent m
of
* F2m
.
* @param k1 The integer k1
where xm +
* xk1 + 1
* represents the reduction polynomial f(z)
.
*/
public X9FieldID(int m, int k1)
{
this(m, k1, 0, 0);
}
/**
* Constructor for elliptic curves over binary fields
* F2m
.
* @param m The exponent m
of
* F2m
.
* @param k1 The integer k1
where xm +
* xk3 + xk2 + xk1 + 1
* represents the reduction polynomial f(z)
.
* @param k2 The integer k2
where xm +
* xk3 + xk2 + xk1 + 1
* represents the reduction polynomial f(z)
.
* @param k3 The integer k3
where xm +
* xk3 + xk2 + xk1 + 1
* represents the reduction polynomial f(z)
..
*/
public X9FieldID(int m, int k1, int k2, int k3)
{
this.id = characteristic_two_field;
ASN1EncodableVector fieldIdParams = new ASN1EncodableVector();
fieldIdParams.add(new ASN1Integer(m));
if (k2 == 0)
{
if (k3 != 0)
{
throw new IllegalArgumentException("inconsistent k values");
}
fieldIdParams.add(tpBasis);
fieldIdParams.add(new ASN1Integer(k1));
}
else
{
if (k2 <= k1 || k3 <= k2)
{
throw new IllegalArgumentException("inconsistent k values");
}
fieldIdParams.add(ppBasis);
ASN1EncodableVector pentanomialParams = new ASN1EncodableVector();
pentanomialParams.add(new ASN1Integer(k1));
pentanomialParams.add(new ASN1Integer(k2));
pentanomialParams.add(new ASN1Integer(k3));
fieldIdParams.add(new DERSequence(pentanomialParams));
}
this.parameters = new DERSequence(fieldIdParams);
}
private X9FieldID(
ASN1Sequence seq)
{
this.id = ASN1ObjectIdentifier.getInstance(seq.getObjectAt(0));
this.parameters = seq.getObjectAt(1).toASN1Primitive();
}
public static X9FieldID getInstance(Object obj)
{
if (obj instanceof X9FieldID)
{
return (X9FieldID)obj;
}
if (obj != null)
{
return new X9FieldID(ASN1Sequence.getInstance(obj));
}
return null;
}
public ASN1ObjectIdentifier getIdentifier()
{
return id;
}
public ASN1Primitive getParameters()
{
return parameters;
}
/**
* Produce a DER encoding of the following structure.
*
* FieldID ::= SEQUENCE {
* fieldType FIELD-ID.&id({IOSet}),
* parameters FIELD-ID.&Type({IOSet}{@fieldType})
* }
*
*/
public ASN1Primitive toASN1Primitive()
{
ASN1EncodableVector v = new ASN1EncodableVector();
v.add(this.id);
v.add(this.parameters);
return new DERSequence(v);
}
}
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