package edu.iup.barrick.crypto;

import java.math.BigInteger;

/**
 * Implementation of basic RSA Encryption/Descryption Algorithm
 * @author Matthew J. Barrick
 */
public class RSA {
    /** 
     * Constructor is declared as private, since this class holds only 
     * static methods, and should never be instantiated
     */
    private RSA() { }

	
	
// STATIC FIELDS ///////////////////////////////////////////////////////////////
    /**
     * Generate Key pair for RSA Algorithm
     * @param p Prime p for RSA Key Generation
     * @param q Prime q for RSA Key Generation
     * @param e Choosen e for RSA Key Generation
     * @return Array containing RSA Key {Public Key, Private Key, n}
     */
    static public BigInteger[] generateKey(BigInteger p, BigInteger q, 
		    				BigInteger e) 
    {
        BigInteger[] result = new BigInteger[3];
        BigInteger phi = p.subtract(BigInteger.ONE)
		.multiply(q.subtract(BigInteger.ONE));
        result[0] = e;
        result[1] = e.modInverse(phi);
        result[2] = p.multiply(q);
        return result;
    }

}