Various minor cleanups noted during C# port

7 files changed, 61 insertions, 89 deletions

diff --git a/core/src/main/java/org/bouncycastle/math/ec/Nat.java b/core/src/main/java/org/bouncycastle/math/ec/Nat.java
index fee1317d..c2bfdbfd 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/Nat.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/Nat.java
@@ -32,18 +32,18 @@ public abstract class Nat
         return (int)c;
     }
 
-    public static int addDWord(int len, long x, int[] z, int zOff)
-    {
-        // assert zOff < (len - 2);
-        long c = x;
-        c += (z[zOff + 0] & M);
-        z[zOff + 0] = (int)c;
-        c >>>= 32;
-        c += (z[zOff + 1] & M);
-        z[zOff + 1] = (int)c;
-        c >>>= 32;
-        return c == 0 ? 0 : inc(len, z, zOff + 2);
-    }
+//    public static int addDWord(int len, long x, int[] z, int zOff)
+//    {
+//        // assert zOff < (len - 2);
+//        long c = x;
+//        c += (z[zOff + 0] & M);
+//        z[zOff + 0] = (int)c;
+//        c >>>= 32;
+//        c += (z[zOff + 1] & M);
+//        z[zOff + 1] = (int)c;
+//        c >>>= 32;
+//        return c == 0 ? 0 : inc(len, z, zOff + 2);
+//    }
 
     public static int addExt(int len, int[] xx, int[] yy, int[] zz)
     {
@@ -129,7 +129,11 @@ public abstract class Nat
         {
             return x[0] & 1;
         }
-        int w = bit >>> 5;
+        int w = bit >> 5;
+        if ((w - Integer.MIN_VALUE) > x.length)
+        {
+            return 0;
+        }
         int b = bit & 31;
         return (x[w] >>> b) & 1;
     }
@@ -208,11 +212,7 @@ public abstract class Nat
 
     public static boolean isZero(int len, int[] x)
     {
-        if (x[0] != 0)
-        {
-            return false;
-        }
-        for (int i = 1; i < len; ++i)
+        for (int i = 0; i < len; ++i)
         {
             if (x[i] != 0)
             {
@@ -224,12 +224,8 @@ public abstract class Nat
 
     public static boolean isZeroExt(int len, int[] xx)
     {
-        if (xx[0] != 0)
-        {
-            return false;
-        }
         int extLen = len << 1;
-        for (int i = 1; i < extLen; ++i)
+        for (int i = 0; i < extLen; ++i)
         {
             if (xx[i] != 0)
             {
@@ -430,17 +426,17 @@ public abstract class Nat
         return (int)c;
     }
 
-    public static int subDWord(int len, long x, int[] z)
-    {
-        long c = -x;
-        c += (z[0] & M);
-        z[0] = (int)c;
-        c >>= 32;
-        c += (z[1] & M);
-        z[1] = (int)c;
-        c >>= 32;
-        return c == 0 ? 0 : dec(len, z, 2);
-    }
+//    public static int subDWord(int len, long x, int[] z)
+//    {
+//        long c = -x;
+//        c += (z[0] & M);
+//        z[0] = (int)c;
+//        c >>= 32;
+//        c += (z[1] & M);
+//        z[1] = (int)c;
+//        c >>= 32;
+//        return c == 0 ? 0 : dec(len, z, 2);
+//    }
 
     public static int subExt(int len, int[] xx, int[] yy, int[] zz)
     {
diff --git a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/Nat256.java b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/Nat256.java
index c2de5113..0aa2d217 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/Nat256.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/Nat256.java
@@ -68,6 +68,7 @@ public abstract class Nat256
         return (int)c;
     }
 
+    // TODO Re-write to allow full range for x?
     public static int addDWord(long x, int[] z, int zOff)
     {
         // assert zOff < 6;
@@ -262,11 +263,7 @@ public abstract class Nat256
 
     public static boolean isZero(int[] x)
     {
-        if (x[0] != 0)
-        {
-            return false;
-        }
-        for (int i = 1; i < 8; ++i)
+        for (int i = 0; i < 8; ++i)
         {
             if (x[i] != 0)
             {
@@ -278,11 +275,7 @@ public abstract class Nat256
 
     public static boolean isZeroExt(int[] xx)
     {
-        if (xx[0] != 0)
-        {
-            return false;
-        }
-        for (int i = 1; i < 16; ++i)
+        for (int i = 0; i < 16; ++i)
         {
             if (xx[i] != 0)
             {
@@ -379,21 +372,6 @@ public abstract class Nat256
         return (int)c;
     }
 
-    public static int squareWordAddExt(int[] x, int xPos, int[] zz)
-    {
-        // assert xPos > 0 && xPos < 8;
-        long c = 0, xVal = x[xPos] & M;
-        int i = 0;
-        do
-        {
-            c += xVal * (x[i] & M) + (zz[xPos + i] & M);
-            zz[xPos + i] = (int)c;
-            c >>>= 32;
-        }
-        while (++i < xPos);
-        return (int)c;
-    }
-
     public static int mulWordDwordAdd(int x, long y, int[] z, int zOff)
     {
         // assert zOff < 5;
@@ -612,17 +590,11 @@ public abstract class Nat256
             zz[7] = (int)zz_7;
             zz_8 += (zz_7 >>> 32) + x_7 * x_1;
             zz_9 += (zz_8 >>> 32) + x_7 * x_2;
-            zz_8 &= M;
             zz_10 += (zz_9 >>> 32) + x_7 * x_3;
-            zz_9 &= M;
             zz_11 += (zz_10 >>> 32) + x_7 * x_4;
-            zz_10 &= M;
             zz_12 += (zz_11 >>> 32) + x_7 * x_5;
-            zz_11 &= M;
             zz_13 += (zz_12 >>> 32) + x_7 * x_6;
-            zz_12 &= M;
             zz_14 += zz_13 >>> 32;
-            zz_13 &= M;
         }
 
         zz[8] = (int)zz_8;
@@ -637,6 +609,21 @@ public abstract class Nat256
         shiftUpBit(zz, 16, (int)x_0 << 31);
     }
 
+    public static int squareWordAddExt(int[] x, int xPos, int[] zz)
+    {
+        // assert xPos > 0 && xPos < 8;
+        long c = 0, xVal = x[xPos] & M;
+        int i = 0;
+        do
+        {
+            c += xVal * (x[i] & M) + (zz[xPos + i] & M);
+            zz[xPos + i] = (int)c;
+            c >>>= 32;
+        }
+        while (++i < xPos);
+        return (int)c;
+    }
+
     public static int sub(int[] x, int[] y, int[] z)
     {
         long c = 0;
@@ -697,16 +684,17 @@ public abstract class Nat256
         return (int)c;
     }
 
+    // TODO Re-write to allow full range for x?
     public static int subDWord(long x, int[] z)
     {
-        x = -x;
-        x += (z[0] & M);
-        z[0] = (int)x;
-        x >>= 32;
-        x += (z[1] & M);
-        z[1] = (int)x;
-        x >>= 32;
-        return x == 0 ? 0 : dec(z, 2);
+        long c = -x;
+        c += (z[0] & M);
+        z[0] = (int)c;
+        c >>= 32;
+        c += (z[1] & M);
+        z[1] = (int)c;
+        c >>= 32;
+        return c == 0 ? 0 : dec(z, 2);
     }
 
     public static int subExt(int[] xx, int[] yy, int[] zz)
diff --git a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1Curve.java b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1Curve.java
index bcdc70b5..5f5f17cf 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1Curve.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1Curve.java
@@ -13,7 +13,6 @@ public class SecP256K1Curve extends ECCurve
 {
     public static final BigInteger q = new BigInteger(1,
         Hex.decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F"));
-    public static final BigInteger r = ECConstants.ONE.shiftLeft(256).subtract(q);
 
     private static final int SECP256K1_DEFAULT_COORDS = COORD_JACOBIAN;
 
diff --git a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1FieldElement.java b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1FieldElement.java
index a415fab6..57828917 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1FieldElement.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1FieldElement.java
@@ -9,7 +9,6 @@ import org.bouncycastle.util.Arrays;
 public class SecP256K1FieldElement extends ECFieldElement
 {
     public static final BigInteger Q = SecP256K1Curve.q;
-    public static final BigInteger Qr = SecP256K1Curve.r;
 
     protected int[] x;
 
@@ -23,7 +22,7 @@ public class SecP256K1FieldElement extends ECFieldElement
         this.x = SecP256K1Field.fromBigInteger(x);
     }
 
-    protected SecP256K1FieldElement()
+    public SecP256K1FieldElement()
     {
         this.x = Nat256.create();
     }
@@ -63,11 +62,6 @@ public class SecP256K1FieldElement extends ECFieldElement
         return Q.bitLength();
     }
 
-    public BigInteger getQ()
-    {
-        return Q;
-    }
-
     public ECFieldElement add(ECFieldElement b)
     {
         int[] z = Nat256.create();
diff --git a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1Point.java b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1Point.java
index 15820b8a..f1d07cad 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1Point.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256K1Point.java
@@ -42,7 +42,7 @@ public class SecP256K1Point extends ECPoint
     {
         super(curve, x, y);
 
-        if ((x != null && y == null) || (x == null && y != null))
+        if ((x == null) != (y == null))
         {
             throw new IllegalArgumentException("Exactly one of the field elements is null");
         }
diff --git a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1FieldElement.java b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1FieldElement.java
index c415e65e..03895cfb 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1FieldElement.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1FieldElement.java
@@ -23,7 +23,7 @@ public class SecP256R1FieldElement extends ECFieldElement
         this.x = SecP256R1Field.fromBigInteger(x);
     }
 
-    protected SecP256R1FieldElement()
+    public SecP256R1FieldElement()
     {
         this.x = Nat256.create();
     }
@@ -63,11 +63,6 @@ public class SecP256R1FieldElement extends ECFieldElement
         return Q.bitLength();
     }
 
-    public BigInteger getQ()
-    {
-        return Q;
-    }
-
     public ECFieldElement add(ECFieldElement b)
     {
         int[] z = Nat256.create();
diff --git a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1Point.java b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1Point.java
index ca6ae008..7ce96c45 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1Point.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1Point.java
@@ -42,7 +42,7 @@ public class SecP256R1Point extends ECPoint
     {
         super(curve, x, y);
 
-        if ((x != null && y == null) || (x == null && y != null))
+        if ((x == null) != (y == null))
         {
             throw new IllegalArgumentException("Exactly one of the field elements is null");
         }