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helper methods to encode and decode Strings using the Base64 encoder and decoder
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import javax.crypto.Cipher; | |
import java.security.KeyPair; | |
import java.security.KeyPairGenerator; | |
import java.security.PrivateKey; | |
import java.security.PublicKey; | |
import java.util.Base64; | |
/** | |
* @author Anass AIT BEN EL ARBI | |
* <ul> | |
* <li>RSA/ECB/PKCS1Padding (1024, 2048)</li> | |
* </ul> | |
* <p> | |
* for more details @see <a href="https://docs.oracle.com/javase/7/docs/api/javax/crypto/Cipher.html">Java Ciphers</a> | |
*/ | |
public class RSA { | |
private PrivateKey privateKey; | |
private PublicKey publicKey; | |
public RSA() { | |
try { | |
KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA"); | |
generator.initialize(1024); | |
KeyPair pair = generator.generateKeyPair(); | |
privateKey = pair.getPrivate(); | |
publicKey = pair.getPublic(); | |
} catch (Exception ignored) { | |
} | |
} | |
public String encrypt(String message) throws Exception{ | |
byte[] messageToBytes = message.getBytes(); | |
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); | |
cipher.init(Cipher.ENCRYPT_MODE,publicKey); | |
byte[] encryptedBytes = cipher.doFinal(messageToBytes); | |
return encode(encryptedBytes); | |
} | |
private String encode(byte[] data){ | |
return Base64.getEncoder().encodeToString(data); | |
} | |
public String decrypt(String encryptedMessage) throws Exception{ | |
byte[] encryptedBytes = decode(encryptedMessage); | |
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); | |
cipher.init(Cipher.DECRYPT_MODE,privateKey); | |
byte[] decryptedMessage = cipher.doFinal(encryptedBytes); | |
return new String(decryptedMessage,"UTF8"); | |
} | |
private byte[] decode(String data){ | |
return Base64.getDecoder().decode(data); | |
} | |
public static void main(String[] args) { | |
RSA rsa = new RSA(); | |
try{ | |
String encryptedMessage = rsa.encrypt("Hello World"); | |
String decryptedMessage = rsa.decrypt(encryptedMessage); | |
System.err.println("Encrypted:\n"+encryptedMessage); | |
System.err.println("Decrypted:\n"+decryptedMessage); | |
}catch (Exception ingored){} | |
} | |
} |
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