package org.bouncycastle.asn1.x9;

import java.math.BigInteger;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.math.ec.ECFieldElement;

class for processing an FieldElement as a DER object.
/** * class for processing an FieldElement as a DER object. */
public class X9FieldElement extends ASN1Encodable { protected ECFieldElement f; private static X9IntegerConverter converter = new X9IntegerConverter(); public X9FieldElement(ECFieldElement f) { this.f = f; } public X9FieldElement(BigInteger p, ASN1OctetString s) { this(new ECFieldElement.Fp(p, new BigInteger(1, s.getOctets()))); } public X9FieldElement(int m, int k1, int k2, int k3, ASN1OctetString s) { this(new ECFieldElement.F2m(m, k1, k2, k3, new BigInteger(1, s.getOctets()))); } public ECFieldElement getValue() { return f; }
Produce an object suitable for an ASN1OutputStream.
 FieldElement ::= OCTET STRING

  1. if q is an odd prime then the field element is processed as an Integer and converted to an octet string according to x 9.62 4.3.1.
  2. if q is 2m then the bit string contained in the field element is converted into an octet string with the same ordering padded at the front if necessary.
/** * Produce an object suitable for an ASN1OutputStream. * <pre> * FieldElement ::= OCTET STRING * </pre> * <p> * <ol> * <li> if <i>q</i> is an odd prime then the field element is * processed as an Integer and converted to an octet string * according to x 9.62 4.3.1.</li> * <li> if <i>q</i> is 2<sup>m</sup> then the bit string * contained in the field element is converted into an octet * string with the same ordering padded at the front if necessary. * </li> * </ol> */
public DERObject toASN1Object() { int byteCount = converter.getByteLength(f); byte[] paddedBigInteger = converter.integerToBytes(f.toBigInteger(), byteCount); return new DEROctetString(paddedBigInteger); } }