org.bouncycastle.crypto.params.DSAPublicKeyParameters.java Source code

Introduction

Here is the source code for org.bouncycastle.crypto.params.DSAPublicKeyParameters.java

Source

package org.bouncycastle.crypto.params;

import java.math.BigInteger;

public class DSAPublicKeyParameters extends DSAKeyParameters {
    private static final BigInteger ONE = BigInteger.valueOf(1);
    private static final BigInteger TWO = BigInteger.valueOf(2);

    private BigInteger y;

    public DSAPublicKeyParameters(BigInteger y, DSAParameters params) {
        super(false, params);

        this.y = validate(y, params);
    }

    private BigInteger validate(BigInteger y, DSAParameters params) {
        if (params != null) {
            if (TWO.compareTo(y) <= 0 && params.getP().subtract(TWO).compareTo(y) >= 0
                    && ONE.equals(y.modPow(params.getQ(), params.getP()))) {
                return y;
            }

            throw new IllegalArgumentException("y value does not appear to be in correct group");
        } else {
            return y; // we can't validate without params, fortunately we can't use the key either...
        }
    }

    public BigInteger getY() {
        return y;
    }
}