import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;
import java.security.interfaces.*;
import java.math.*;
import java.io.*;

public class Enc_RSA {
	public static void main(String args[]) throws Exception {
		String s = "I love Java";
		// 获取公钥及参数e,n
		FileInputStream f = new FileInputStream("Skey_RSA_pub.dat");
		ObjectInputStream b = new ObjectInputStream(f);
		RSAPublicKey pbk = (RSAPublicKey) b.readObject();
		BigInteger e = pbk.getPublicExponent();
		BigInteger n = pbk.getModulus();
		System.out.println("e= " + e);
		System.out.println("n= " + n);
		// 明文 m
		byte ptext[] = s.getBytes("UTF8");
		BigInteger m = new BigInteger(ptext);
		// 计算密文c,打印
		BigInteger c = m.modPow(e, n);
		System.out.println("c= " + c);
		// 保存密文
		String cs = c.toString();
		BufferedWriter out =
			new BufferedWriter(new OutputStreamWriter(
						new FileOutputStream("Enc_RSA.dat")));
		out.write(cs, 0, cs.length());
		out.close();

	}
}