Use new Math.Field classes in EC curves, and avoid casting in client code

1 files changed, 83 insertions, 61 deletions

diff --git a/crypto/src/asn1/x9/X9FieldID.cs b/crypto/src/asn1/x9/X9FieldID.cs
index c51cc4df2..58823a285 100644
--- a/crypto/src/asn1/x9/X9FieldID.cs
+++ b/crypto/src/asn1/x9/X9FieldID.cs
@@ -1,3 +1,5 @@
+using System;
+
 using Org.BouncyCastle.Math;
 
 namespace Org.BouncyCastle.Asn1.X9
@@ -12,80 +14,100 @@ namespace Org.BouncyCastle.Asn1.X9
         private readonly DerObjectIdentifier	id;
         private readonly Asn1Object parameters;
 
-		/**
-		 * Constructor for elliptic curves over prime fields
-		 * <code>F<sub>2</sub></code>.
-		 * @param primeP The prime <code>p</code> defining the prime field.
-		 */
-		public X9FieldID(
-			BigInteger primeP)
-		{
-			this.id = X9ObjectIdentifiers.PrimeField;
-			this.parameters = new DerInteger(primeP);
-		}
+        /**
+         * Constructor for elliptic curves over prime fields
+         * <code>F<sub>2</sub></code>.
+         * @param primeP The prime <code>p</code> defining the prime field.
+         */
+        public X9FieldID(
+            BigInteger primeP)
+        {
+            this.id = X9ObjectIdentifiers.PrimeField;
+            this.parameters = new DerInteger(primeP);
+        }
 
-		/**
-		 * Constructor for elliptic curves over binary fields
-		 * <code>F<sub>2<sup>m</sup></sub></code>.
-		 * @param m  The exponent <code>m</code> of
-		 * <code>F<sub>2<sup>m</sup></sub></code>.
-		 * @param k1 The integer <code>k1</code> where <code>x<sup>m</sup> +
-		 * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
-		 * represents the reduction polynomial <code>f(z)</code>.
-		 * @param k2 The integer <code>k2</code> where <code>x<sup>m</sup> +
-		 * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
-		 * represents the reduction polynomial <code>f(z)</code>.
-		 * @param k3 The integer <code>k3</code> where <code>x<sup>m</sup> +
-		 * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
-		 * represents the reduction polynomial <code>f(z)</code>..
-		 */
-		public X9FieldID(
-			int m,
-			int k1,
-			int k2,
-			int k3)
-		{
-			this.id = X9ObjectIdentifiers.CharacteristicTwoField;
+        /**
+         * Constructor for elliptic curves over binary fields
+         * <code>F<sub>2<sup>m</sup></sub></code>.
+         * @param m  The exponent <code>m</code> of
+         * <code>F<sub>2<sup>m</sup></sub></code>.
+         * @param k1 The integer <code>k1</code> where <code>x<sup>m</sup> +
+         * x<sup>k1</sup> + 1</code>
+         * represents the reduction polynomial <code>f(z)</code>.
+         */
+        public X9FieldID(int m, int k1)
+            : this(m, k1, 0, 0)
+        {
+        }
 
-			Asn1EncodableVector fieldIdParams = new Asn1EncodableVector(new DerInteger(m));
+        /**
+         * Constructor for elliptic curves over binary fields
+         * <code>F<sub>2<sup>m</sup></sub></code>.
+         * @param m  The exponent <code>m</code> of
+         * <code>F<sub>2<sup>m</sup></sub></code>.
+         * @param k1 The integer <code>k1</code> where <code>x<sup>m</sup> +
+         * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
+         * represents the reduction polynomial <code>f(z)</code>.
+         * @param k2 The integer <code>k2</code> where <code>x<sup>m</sup> +
+         * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
+         * represents the reduction polynomial <code>f(z)</code>.
+         * @param k3 The integer <code>k3</code> where <code>x<sup>m</sup> +
+         * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
+         * represents the reduction polynomial <code>f(z)</code>..
+         */
+        public X9FieldID(
+            int m,
+            int k1,
+            int k2,
+            int k3)
+        {
+            this.id = X9ObjectIdentifiers.CharacteristicTwoField;
+
+            Asn1EncodableVector fieldIdParams = new Asn1EncodableVector(new DerInteger(m));
 
-			if (k2 == 0)
-			{
-				fieldIdParams.Add(
-					X9ObjectIdentifiers.TPBasis,
-					new DerInteger(k1));
-			}
-			else
-			{
-				fieldIdParams.Add(
-					X9ObjectIdentifiers.PPBasis,
-					new DerSequence(
-						new DerInteger(k1),
-						new DerInteger(k2),
-						new DerInteger(k3)));
-			}
+            if (k2 == 0)
+            {
+                if (k3 != 0)
+                    throw new ArgumentException("inconsistent k values");
 
-			this.parameters = new DerSequence(fieldIdParams);
-		}
+                fieldIdParams.Add(
+                    X9ObjectIdentifiers.TPBasis,
+                    new DerInteger(k1));
+            }
+            else
+            {
+                if (k2 <= k1 || k3 <= k2)
+                    throw new ArgumentException("inconsistent k values");
 
-		internal X9FieldID(
-			Asn1Sequence seq)
-		{
-			this.id = (DerObjectIdentifier) seq[0];
-			this.parameters = (Asn1Object) seq[1];
-		}
+                fieldIdParams.Add(
+                    X9ObjectIdentifiers.PPBasis,
+                    new DerSequence(
+                        new DerInteger(k1),
+                        new DerInteger(k2),
+                        new DerInteger(k3)));
+            }
+
+            this.parameters = new DerSequence(fieldIdParams);
+        }
+
+        internal X9FieldID(
+            Asn1Sequence seq)
+        {
+            this.id = (DerObjectIdentifier) seq[0];
+            this.parameters = (Asn1Object) seq[1];
+        }
 
-		public DerObjectIdentifier Identifier
+        public DerObjectIdentifier Identifier
         {
             get { return id; }
         }
 
-		public Asn1Object Parameters
+        public Asn1Object Parameters
         {
             get { return parameters; }
         }
 
-		/**
+        /**
          * Produce a Der encoding of the following structure.
          * <pre>
          *  FieldID ::= Sequence {
@@ -96,7 +118,7 @@ namespace Org.BouncyCastle.Asn1.X9
          */
         public override Asn1Object ToAsn1Object()
         {
-			return new DerSequence(id, parameters);
+            return new DerSequence(id, parameters);
         }
     }
 }