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package org.bouncycastle.asn1.x9;
import java.math.BigInteger;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.math.ec.ECFieldElement;
/**
* class for processing an FieldElement as a DER object.
*/
public class X9FieldElement
extends ASN1Object
{
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.
* <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 ASN1Primitive toASN1Primitive()
{
int byteCount = converter.getByteLength(f);
byte[] paddedBigInteger = converter.integerToBytes(f.toBigInteger(), byteCount);
return new DEROctetString(paddedBigInteger);
}
}
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