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using System;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Math.EC;
namespace Org.BouncyCastle.Asn1.X9
{
/**
* Class for processing an ECFieldElement as a DER object.
*/
public class X9FieldElement
: Asn1Encodable
{
private ECFieldElement f;
public X9FieldElement(
ECFieldElement f)
{
this.f = f;
}
public X9FieldElement(
BigInteger p,
Asn1OctetString s)
: this(new FpFieldElement(p, new BigInteger(1, s.GetOctets())))
{
}
public X9FieldElement(
int m,
int k1,
int k2,
int k3,
Asn1OctetString s)
: this(new F2mFieldElement(m, k1, k2, k3, new BigInteger(1, s.GetOctets())))
{
}
public ECFieldElement Value
{
get { 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>
* </p>
*/
public override Asn1Object ToAsn1Object()
{
int byteCount = X9IntegerConverter.GetByteLength(f);
byte[] paddedBigInteger = X9IntegerConverter.IntegerToBytes(f.ToBigInteger(), byteCount);
return new DerOctetString(paddedBigInteger);
}
}
}
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