NTRUSigningPublicKeyParameters.java

package org.spongycastle.crypto.params;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.spongycastle.math.ntru.polynomial.IntegerPolynomial;

/**
 * A NtruSign public key is essentially a polynomial named <code>h</code>.
 */
public class NTRUSigningPublicKeyParameters
    extends AsymmetricKeyParameter
{
    private NTRUSigningParameters params;
    public IntegerPolynomial h;

    /**
     * Constructs a new public key from a polynomial
     * @param h the polynomial <code>h</code> which determines the key
     * @param params the NtruSign parameters to use
     */
    public NTRUSigningPublicKeyParameters(IntegerPolynomial h, NTRUSigningParameters params) {
        super(false);
        this.h = h;
        this.params = params;
    }
    
    /**
     * Converts a byte array to a polynomial <code>h</code> and constructs a new public key
     * @param b an encoded polynomial
     * @param params the NtruSign parameters to use
     */
    public NTRUSigningPublicKeyParameters(byte[] b, NTRUSigningParameters params) {
        super(false);
        h = IntegerPolynomial.fromBinary(b, params.N, params.q);
        this.params = params;
    }
    
    /**
     * Reads a polynomial <code>h</code> from an input stream and constructs a new public key
     * @param is an input stream
     * @param params the NtruSign parameters to use
     */
    public NTRUSigningPublicKeyParameters(InputStream is, NTRUSigningParameters params) throws IOException {
        super(false);
        h = IntegerPolynomial.fromBinary(is, params.N, params.q);
        this.params = params;
    }



    /**
     * Converts the key to a byte array
     * @return the encoded key
     */
    public byte[] getEncoded() {
        return h.toBinary(params.q);
    }
    
    /**
     * Writes the key to an output stream
     * @param os an output stream
     * @throws IOException
     */
    public void writeTo(OutputStream os) throws IOException {
        os.write(getEncoded());
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((h == null) ? 0 : h.hashCode());
        result = prime * result + ((params == null) ? 0 : params.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        NTRUSigningPublicKeyParameters other = (NTRUSigningPublicKeyParameters) obj;
        if (h == null) {
            if (other.h != null)
                return false;
        } else if (!h.equals(other.h))
            return false;
        if (params == null) {
            if (other.params != null)
                return false;
        } else if (!params.equals(other.params))
            return false;
        return true;
    }
}