pl.kotcrab.crypto.RSAEncrypter.java Source code

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Here is the source code for pl.kotcrab.crypto.RSAEncrypter.java

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/*******************************************************************************
 * Copyright 2014 Pawel Pastuszak
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package pl.kotcrab.crypto;

import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.Security;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

/** RSA encrypter, requires only public key and allows only to encrypt data
 * @author Pawel Pastuszak */
public class RSAEncrypter {

    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    private PublicKey publicKey;
    private Cipher encrypter;

    /** Constructs RSAEncrypter from {@link X509EncodedKeySpec#getEncoded()} encoded with base64
     * @param publicEncodedBase64 base64 string from {@link X509EncodedKeySpec#getEncoded()} bytes */
    public RSAEncrypter(String publicEncodedBase64) {
        this(new X509EncodedKeySpec(Base64.decodeBase64(publicEncodedBase64)));
    }

    /** Constructs RSAEncrypter from {@link X509EncodedKeySpec#getEncoded()}
     * @param publicEncoded bytes from {@link X509EncodedKeySpec#getEncoded()} */
    public RSAEncrypter(byte[] publicEncoded) {
        this(new X509EncodedKeySpec(publicEncoded));
    }

    /** Constructs RSAEcnrypted from the key spec itself
     * @param publicKeySpec key spec */
    public RSAEncrypter(X509EncodedKeySpec publicKeySpec) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA", "BC");

            publicKey = keyFactory.generatePublic(publicKeySpec);

            setupCiphers();
        } catch (GeneralSecurityException e) {
            e.printStackTrace();
        }
    }

    private void setupCiphers() throws GeneralSecurityException {
        encrypter = Cipher.getInstance("RSA/None/PKCS1Padding", "BC");
        encrypter.init(Cipher.ENCRYPT_MODE, publicKey);
    }

    /** Encrypts some data using RSA
     * @param data data to be encrypted
     * @return encrypted data or null if exceptions occurred during encryption. Use {@link RSAEncrypter#encryptSafe(byte[])} if you
     *         want to catch exceptions */
    public byte[] encrypt(byte[] data) {
        try {
            return encrypter.doFinal(data);
        } catch (GeneralSecurityException e) {
            e.printStackTrace();
        }

        return null;
    }

    /** Encrypts some data using RSA. Allows to catch exception if error occurres during encryption
     * @param data data to be encrypted
     * @return encrypted data */
    public byte[] encryptSafe(byte[] data) throws GeneralSecurityException {
        return encrypter.doFinal(data);
    }
}