Question

How to encrypt and decrypt a string in Java

Answer 1

import java.security.KeyPair;
import java.security.Signature;
import java.security.PublicKey;
import java.security.KeyPairGenerator;

import javax.crypto.Cipher;

public class MyClass {
    public static void main(String args[]) throws Exception{
        Signature signature = Signature.getInstance("SHA256withRSA");
      
        KeyPairGenerator keypairgenerator = KeyPairGenerator.getInstance("RSA");
      
        keypairgenerator.initialize(2048);
      
        KeyPair keypair = keypairgenerator.generateKeyPair();   
      
        PublicKey publicKey = keypair.getPublic();  

        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");

        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
	  
        byte[] strarr = "Java programming".getBytes();
        cipher.update(strarr);
	  
        byte[] encrypt  = cipher.doFinal();	 
        System.out.println(new String(encrypt , "UTF8"));


        cipher.init(Cipher.DECRYPT_MODE, keypair.getPrivate());
      
        byte[] decrypt  = cipher.doFinal(encrypt);
        System.out.println("\n" + new String(decrypt));
    }
}



/*
run:

TA�J�������&]�� �	����v1�5F,��ݽ���ж<s;��vg���5�Q@ ���&�0?�s�T
s��7/�	L����u[��`��3��o�=I��4Ay�XO

Java programming

*/

 

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