java处理加密文件---RSA加密和解密

public class RSA {

public static void main(String []args)throws Exception

{

String ptext = "he";

//获取公钥生成参数

KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");

kpg.initialize(1024);

KeyPair keyPair = kpg.genKeyPair();

RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

System.out.println("公共码"+publicKey.getModulus().toString());

byte[] ptexts = ptext.getBytes("UTF8");

BigInteger m = new BigInteger(ptexts);

BigInteger c = m.modPow(publicKey.getPublicExponent(), publicKey.getModulus());

System.out.println("密文"+c);

//System.out.println("d："+privateKey.getPrivateExponent());

System.out.println("私密码"+privateKey.getModulus());

BigInteger jm=c.modPow(privateKey.getPrivateExponent(), privateKey.getModulus());

System.out.println("解码数据"+jm);

byte[] mt =jm.toByteArray();

System.out.print("解码结果");

for(int i=0;i<mt.length;i++){

System.out.print((char)mt[i]);

}

}

}