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      1 package org.bouncycastle.math.ec.custom.sec;
      2 
      3 import java.math.BigInteger;
      4 
      5 import org.bouncycastle.math.ec.ECFieldElement;
      6 import org.bouncycastle.math.raw.Mod;
      7 import org.bouncycastle.math.raw.Nat192;
      8 import org.bouncycastle.util.Arrays;
      9 
     10 public class SecP192R1FieldElement extends ECFieldElement
     11 {
     12     public static final BigInteger Q = SecP192R1Curve.q;
     13 
     14     protected int[] x;
     15 
     16     public SecP192R1FieldElement(BigInteger x)
     17     {
     18         if (x == null || x.signum() < 0 || x.compareTo(Q) >= 0)
     19         {
     20             throw new IllegalArgumentException("x value invalid for SecP192R1FieldElement");
     21         }
     22 
     23         this.x = SecP192R1Field.fromBigInteger(x);
     24     }
     25 
     26     public SecP192R1FieldElement()
     27     {
     28         this.x = Nat192.create();
     29     }
     30 
     31     protected SecP192R1FieldElement(int[] x)
     32     {
     33         this.x = x;
     34     }
     35 
     36     public boolean isZero()
     37     {
     38         return Nat192.isZero(x);
     39     }
     40 
     41     public boolean isOne()
     42     {
     43         return Nat192.isOne(x);
     44     }
     45 
     46     public boolean testBitZero()
     47     {
     48         return Nat192.getBit(x, 0) == 1;
     49     }
     50 
     51     public BigInteger toBigInteger()
     52     {
     53         return Nat192.toBigInteger(x);
     54     }
     55 
     56     public String getFieldName()
     57     {
     58         return "SecP192R1Field";
     59     }
     60 
     61     public int getFieldSize()
     62     {
     63         return Q.bitLength();
     64     }
     65 
     66     public ECFieldElement add(ECFieldElement b)
     67     {
     68         int[] z = Nat192.create();
     69         SecP192R1Field.add(x, ((SecP192R1FieldElement)b).x, z);
     70         return new SecP192R1FieldElement(z);
     71     }
     72 
     73     public ECFieldElement addOne()
     74     {
     75         int[] z = Nat192.create();
     76         SecP192R1Field.addOne(x, z);
     77         return new SecP192R1FieldElement(z);
     78     }
     79 
     80     public ECFieldElement subtract(ECFieldElement b)
     81     {
     82         int[] z = Nat192.create();
     83         SecP192R1Field.subtract(x, ((SecP192R1FieldElement)b).x, z);
     84         return new SecP192R1FieldElement(z);
     85     }
     86 
     87     public ECFieldElement multiply(ECFieldElement b)
     88     {
     89         int[] z = Nat192.create();
     90         SecP192R1Field.multiply(x, ((SecP192R1FieldElement)b).x, z);
     91         return new SecP192R1FieldElement(z);
     92     }
     93 
     94     public ECFieldElement divide(ECFieldElement b)
     95     {
     96 //        return multiply(b.invert());
     97         int[] z = Nat192.create();
     98         Mod.invert(SecP192R1Field.P, ((SecP192R1FieldElement)b).x, z);
     99         SecP192R1Field.multiply(z, x, z);
    100         return new SecP192R1FieldElement(z);
    101     }
    102 
    103     public ECFieldElement negate()
    104     {
    105         int[] z = Nat192.create();
    106         SecP192R1Field.negate(x, z);
    107         return new SecP192R1FieldElement(z);
    108     }
    109 
    110     public ECFieldElement square()
    111     {
    112         int[] z = Nat192.create();
    113         SecP192R1Field.square(x, z);
    114         return new SecP192R1FieldElement(z);
    115     }
    116 
    117     public ECFieldElement invert()
    118     {
    119 //        return new SecP192R1FieldElement(toBigInteger().modInverse(Q));
    120         int[] z = Nat192.create();
    121         Mod.invert(SecP192R1Field.P, x, z);
    122         return new SecP192R1FieldElement(z);
    123     }
    124 
    125     // D.1.4 91
    126     /**
    127      * return a sqrt root - the routine verifies that the calculation returns the right value - if
    128      * none exists it returns null.
    129      */
    130     public ECFieldElement sqrt()
    131     {
    132         // Raise this element to the exponent 2^190 - 2^62
    133 
    134         int[] x1 = this.x;
    135         if (Nat192.isZero(x1) || Nat192.isOne(x1))
    136         {
    137             return this;
    138         }
    139 
    140         int[] t1 = Nat192.create();
    141         int[] t2 = Nat192.create();
    142 
    143         SecP192R1Field.square(x1, t1);
    144         SecP192R1Field.multiply(t1, x1, t1);
    145 
    146         SecP192R1Field.squareN(t1, 2, t2);
    147         SecP192R1Field.multiply(t2, t1, t2);
    148 
    149         SecP192R1Field.squareN(t2, 4, t1);
    150         SecP192R1Field.multiply(t1, t2, t1);
    151 
    152         SecP192R1Field.squareN(t1, 8, t2);
    153         SecP192R1Field.multiply(t2, t1, t2);
    154 
    155         SecP192R1Field.squareN(t2, 16, t1);
    156         SecP192R1Field.multiply(t1, t2, t1);
    157 
    158         SecP192R1Field.squareN(t1, 32, t2);
    159         SecP192R1Field.multiply(t2, t1, t2);
    160 
    161         SecP192R1Field.squareN(t2, 64, t1);
    162         SecP192R1Field.multiply(t1, t2, t1);
    163 
    164         SecP192R1Field.squareN(t1, 62, t1);
    165         SecP192R1Field.square(t1, t2);
    166 
    167         return Nat192.eq(x1, t2) ? new SecP192R1FieldElement(t1) : null;
    168     }
    169 
    170     public boolean equals(Object other)
    171     {
    172         if (other == this)
    173         {
    174             return true;
    175         }
    176 
    177         if (!(other instanceof SecP192R1FieldElement))
    178         {
    179             return false;
    180         }
    181 
    182         SecP192R1FieldElement o = (SecP192R1FieldElement)other;
    183         return Nat192.eq(x, o.x);
    184     }
    185 
    186     public int hashCode()
    187     {
    188         return Q.hashCode() ^ Arrays.hashCode(x, 0, 6);
    189     }
    190 }
    191