EdDSA-Java by str4d

To the extent possible under law, the person who associated CC0 with
EdDSA-Java has waived all copyright and related or neighboring rights
to EdDSA-Java.

You should have received a copy of the CC0 legalcode along with this
work. If not, see <https://creativecommons.org/publicdomain/zero/1.0/>.

package net.i2p.crypto.eddsa.math;

import java.io.Serializable;

/**

 Note: concrete subclasses must implement hashCode() and equals()
/

public abstract class FieldElement implements Serializable {

private static final long serialVersionUID = 1239527465875676L;

protected final Field f;

public FieldElement(Field f) {
    if (null == f) {
        throw new IllegalArgumentException("field cannot be null");
    }
    this.f = f;
}

/**
   Encode a FieldElement in its $(b-1)$-bit encoding.
   @return the $(b-1)$-bit encoding of this FieldElement.
  /
public byte[] toByteArray() {
    return f.getEncoding().encode(this);
}

public abstract boolean isNonZero();

public boolean isNegative() {
    return f.getEncoding().isNegative(this);
}

public abstract FieldElement add(FieldElement val);

public FieldElement addOne() {
    return add(f.ONE);
}

public abstract FieldElement subtract(FieldElement val);

public FieldElement subtractOne() {
    return subtract(f.ONE);
}

public abstract FieldElement negate();

public FieldElement divide(FieldElement val) {
    return multiply(val.invert());
}

public abstract FieldElement multiply(FieldElement val);

public abstract FieldElement square();

public abstract FieldElement squareAndDouble();

public abstract FieldElement invert();

public abstract FieldElement pow22523();

public abstract FieldElement cmov(FieldElement val, final int b);

// Note: concrete subclasses must implement hashCode() and equals()

}