1 files changed, 186 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/x9/X9ECParameters.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/x9/X9ECParameters.java
new file mode 100644
index 000000000..80eb35fe2
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/x9/X9ECParameters.java
@@ -0,0 +1,186 @@
+package org.spongycastle.asn1.x9;
+
+import java.math.BigInteger;
+
+import org.spongycastle.asn1.ASN1EncodableVector;
+import org.spongycastle.asn1.ASN1Integer;
+import org.spongycastle.asn1.ASN1Object;
+import org.spongycastle.asn1.ASN1OctetString;
+import org.spongycastle.asn1.ASN1Primitive;
+import org.spongycastle.asn1.ASN1Sequence;
+import org.spongycastle.asn1.DERSequence;
+import org.spongycastle.math.ec.ECCurve;
+import org.spongycastle.math.ec.ECPoint;
+
+/**
+ * ASN.1 def for Elliptic-Curve ECParameters structure. See
+ * X9.62, for further details.
+ */
+public class X9ECParameters
+    extends ASN1Object
+    implements X9ObjectIdentifiers
+{
+    private static final BigInteger   ONE = BigInteger.valueOf(1);
+
+    private X9FieldID           fieldID;
+    private ECCurve             curve;
+    private ECPoint             g;
+    private BigInteger          n;
+    private BigInteger          h;
+    private byte[]              seed;
+
+    private X9ECParameters(
+        ASN1Sequence  seq)
+    {
+        if (!(seq.getObjectAt(0) instanceof ASN1Integer)
+           || !((ASN1Integer)seq.getObjectAt(0)).getValue().equals(ONE))
+        {
+            throw new IllegalArgumentException("bad version in X9ECParameters");
+        }
+
+        X9Curve     x9c = new X9Curve(
+                        X9FieldID.getInstance(seq.getObjectAt(1)),
+                        ASN1Sequence.getInstance(seq.getObjectAt(2)));
+
+        this.curve = x9c.getCurve();
+        Object p = seq.getObjectAt(3);
+
+        if (p instanceof X9ECPoint)
+        {
+            this.g = ((X9ECPoint)p).getPoint();
+        }
+        else
+        {
+            this.g = new X9ECPoint(curve, (ASN1OctetString)p).getPoint();
+        }
+
+        this.n = ((ASN1Integer)seq.getObjectAt(4)).getValue();
+        this.seed = x9c.getSeed();
+
+        if (seq.size() == 6)
+        {
+            this.h = ((ASN1Integer)seq.getObjectAt(5)).getValue();
+        }
+    }
+
+    public static X9ECParameters getInstance(Object obj)
+    {
+        if (obj instanceof X9ECParameters)
+        {
+            return (X9ECParameters)obj;
+        }
+
+        if (obj != null)
+        {
+            return new X9ECParameters(ASN1Sequence.getInstance(obj));
+        }
+
+        return null;
+    }
+
+    public X9ECParameters(
+        ECCurve     curve,
+        ECPoint     g,
+        BigInteger  n)
+    {
+        this(curve, g, n, ONE, null);
+    }
+
+    public X9ECParameters(
+        ECCurve     curve,
+        ECPoint     g,
+        BigInteger  n,
+        BigInteger  h)
+    {
+        this(curve, g, n, h, null);
+    }
+
+    public X9ECParameters(
+        ECCurve     curve,
+        ECPoint     g,
+        BigInteger  n,
+        BigInteger  h,
+        byte[]      seed)
+    {
+        this.curve = curve;
+        this.g = g.normalize();
+        this.n = n;
+        this.h = h;
+        this.seed = seed;
+
+        if (curve instanceof ECCurve.Fp)
+        {
+            this.fieldID = new X9FieldID(((ECCurve.Fp)curve).getQ());
+        }
+        else
+        {
+            if (curve instanceof ECCurve.F2m)
+            {
+                ECCurve.F2m curveF2m = (ECCurve.F2m)curve;
+                this.fieldID = new X9FieldID(curveF2m.getM(), curveF2m.getK1(),
+                    curveF2m.getK2(), curveF2m.getK3());
+            }
+        }
+    }
+
+    public ECCurve getCurve()
+    {
+        return curve;
+    }
+
+    public ECPoint getG()
+    {
+        return g;
+    }
+
+    public BigInteger getN()
+    {
+        return n;
+    }
+
+    public BigInteger getH()
+    {
+        if (h == null)
+        {
+            return ONE;        // TODO - this should be calculated, it will cause issues with custom curves.
+        }
+
+        return h;
+    }
+
+    public byte[] getSeed()
+    {
+        return seed;
+    }
+
+    /**
+     * Produce an object suitable for an ASN1OutputStream.
+     * <pre>
+     *  ECParameters ::= SEQUENCE {
+     *      version         INTEGER { ecpVer1(1) } (ecpVer1),
+     *      fieldID         FieldID {{FieldTypes}},
+     *      curve           X9Curve,
+     *      base            X9ECPoint,
+     *      order           INTEGER,
+     *      cofactor        INTEGER OPTIONAL
+     *  }
+     * </pre>
+     */
+    public ASN1Primitive toASN1Primitive()
+    {
+        ASN1EncodableVector v = new ASN1EncodableVector();
+
+        v.add(new ASN1Integer(1));
+        v.add(fieldID);
+        v.add(new X9Curve(curve, seed));
+        v.add(new X9ECPoint(g));
+        v.add(new ASN1Integer(n));
+
+        if (h != null)
+        {
+            v.add(new ASN1Integer(h));
+        }
+
+        return new DERSequence(v);
+    }
+}