diff --git a/crypto/src/asn1/x9/X9ECParameters.cs b/crypto/src/asn1/x9/X9ECParameters.cs
index d025b36ce..6389defa8 100644
--- a/crypto/src/asn1/x9/X9ECParameters.cs
+++ b/crypto/src/asn1/x9/X9ECParameters.cs
@@ -2,6 +2,7 @@ using System;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Math.EC;
+using Org.BouncyCastle.Math.Field;
namespace Org.BouncyCastle.Asn1.X9
{
@@ -19,7 +20,7 @@ namespace Org.BouncyCastle.Asn1.X9
private BigInteger h;
private byte[] seed;
- public X9ECParameters(
+ public X9ECParameters(
Asn1Sequence seq)
{
if (!(seq[0] is DerInteger)
@@ -28,7 +29,7 @@ namespace Org.BouncyCastle.Asn1.X9
throw new ArgumentException("bad version in X9ECParameters");
}
- X9Curve x9c = null;
+ X9Curve x9c = null;
if (seq[2] is X9Curve)
{
x9c = (X9Curve) seq[2];
@@ -36,14 +37,14 @@ namespace Org.BouncyCastle.Asn1.X9
else
{
x9c = new X9Curve(
- new X9FieldID(
- (Asn1Sequence) seq[1]),
- (Asn1Sequence) seq[2]);
+ new X9FieldID(
+ (Asn1Sequence) seq[1]),
+ (Asn1Sequence) seq[2]);
}
- this.curve = x9c.Curve;
+ this.curve = x9c.Curve;
- if (seq[3] is X9ECPoint)
+ if (seq[3] is X9ECPoint)
{
this.g = ((X9ECPoint) seq[3]).Point;
}
@@ -52,16 +53,16 @@ namespace Org.BouncyCastle.Asn1.X9
this.g = new X9ECPoint(curve, (Asn1OctetString) seq[3]).Point;
}
- this.n = ((DerInteger) seq[4]).Value;
+ this.n = ((DerInteger) seq[4]).Value;
this.seed = x9c.GetSeed();
- if (seq.Count == 6)
+ if (seq.Count == 6)
{
this.h = ((DerInteger) seq[5]).Value;
}
}
- public X9ECParameters(
+ public X9ECParameters(
ECCurve curve,
ECPoint g,
BigInteger n)
@@ -69,7 +70,7 @@ namespace Org.BouncyCastle.Asn1.X9
{
}
- public X9ECParameters(
+ public X9ECParameters(
ECCurve curve,
ECPoint g,
BigInteger n,
@@ -78,7 +79,7 @@ namespace Org.BouncyCastle.Asn1.X9
{
}
- public X9ECParameters(
+ public X9ECParameters(
ECCurve curve,
ECPoint g,
BigInteger n,
@@ -91,53 +92,68 @@ namespace Org.BouncyCastle.Asn1.X9
this.h = h;
this.seed = seed;
- if (curve is FpCurve)
- {
- this.fieldID = new X9FieldID(((FpCurve) curve).Q);
- }
- else if (curve is F2mCurve)
- {
- F2mCurve curveF2m = (F2mCurve) curve;
- this.fieldID = new X9FieldID(curveF2m.M, curveF2m.K1,
- curveF2m.K2, curveF2m.K3);
- }
+ if (ECAlgorithms.IsFpCurve(curve))
+ {
+ this.fieldID = new X9FieldID(curve.Field.Characteristic);
+ }
+ else if (ECAlgorithms.IsF2mCurve(curve))
+ {
+ IPolynomialExtensionField field = (IPolynomialExtensionField)curve.Field;
+ int[] exponents = field.MinimalPolynomial.GetExponentsPresent();
+ if (exponents.Length == 3)
+ {
+ this.fieldID = new X9FieldID(exponents[2], exponents[1]);
+ }
+ else if (exponents.Length == 5)
+ {
+ this.fieldID = new X9FieldID(exponents[4], exponents[1], exponents[2], exponents[3]);
+ }
+ else
+ {
+ throw new ArgumentException("Only trinomial and pentomial curves are supported");
+ }
+ }
+ else
+ {
+ throw new ArgumentException("'curve' is of an unsupported type");
+ }
}
- public ECCurve Curve
+ public ECCurve Curve
{
- get { return curve; }
+ get { return curve; }
}
- public ECPoint G
+ public ECPoint G
{
get { return g; }
}
- public BigInteger N
+ public BigInteger N
{
get { return n; }
}
- public BigInteger H
+ public BigInteger H
{
get
- {
- if (h == null)
- {
- // TODO - this should be calculated, it will cause issues with custom curves.
- return BigInteger.One;
- }
-
- return h;
- }
+ {
+ if (h == null)
+ {
+ // TODO - this should be calculated, it will cause issues with custom curves.
+ return BigInteger.One;
+ }
+
+ return h;
+ }
}
- public byte[] GetSeed()
+ public byte[] GetSeed()
{
return seed;
}
- /**
+ /**
* Produce an object suitable for an Asn1OutputStream.
* <pre>
* ECParameters ::= Sequence {
@@ -153,18 +169,18 @@ namespace Org.BouncyCastle.Asn1.X9
public override Asn1Object ToAsn1Object()
{
Asn1EncodableVector v = new Asn1EncodableVector(
- new DerInteger(1),
- fieldID,
- new X9Curve(curve, seed),
- new X9ECPoint(g),
- new DerInteger(n));
+ new DerInteger(1),
+ fieldID,
+ new X9Curve(curve, seed),
+ new X9ECPoint(g),
+ new DerInteger(n));
- if (h != null)
+ if (h != null)
{
v.Add(new DerInteger(h));
}
- return new DerSequence(v);
+ return new DerSequence(v);
}
}
}
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