001/**
002 *
003 * Copyright 2017 Paul Schaub, 2019-2021 Florian Schmaus
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.jivesoftware.smackx.omemo.internal;
018
019import java.nio.charset.StandardCharsets;
020import java.security.InvalidAlgorithmParameterException;
021import java.security.InvalidKeyException;
022import java.security.NoSuchAlgorithmException;
023
024import javax.crypto.BadPaddingException;
025import javax.crypto.Cipher;
026import javax.crypto.IllegalBlockSizeException;
027import javax.crypto.NoSuchPaddingException;
028import javax.crypto.SecretKey;
029import javax.crypto.spec.IvParameterSpec;
030import javax.crypto.spec.SecretKeySpec;
031
032import org.jivesoftware.smack.util.RandomUtil;
033import org.jivesoftware.smackx.omemo.util.OmemoConstants;
034import org.jivesoftware.smackx.omemo.util.OmemoMessageBuilder;
035
036public class OmemoAesCipher {
037
038    static {
039        byte[] iv = OmemoMessageBuilder.generateIv();
040        byte[] key = new byte[16];
041        RandomUtil.fillWithSecureRandom(key);
042
043        try {
044            encryptAesGcmNoPadding("This is just a test", key, iv);
045        } catch (InvalidKeyException | NoSuchAlgorithmException | NoSuchPaddingException
046                        | InvalidAlgorithmParameterException | IllegalBlockSizeException | BadPaddingException e) {
047            String message = "Unable to perform " + OmemoConstants.Crypto.CIPHERMODE
048                            + " operation requires by OMEMO. Ensure that a suitable crypto provider for is available."
049                            + " For example Bouncycastle on Android (BouncyCastleProvider)";
050            throw new AssertionError(message);
051        }
052    }
053
054    private enum CipherOpmode {
055        encrypt(Cipher.ENCRYPT_MODE),
056        decrypt(Cipher.DECRYPT_MODE),
057        ;
058
059        public final int opmodeInt;
060
061        CipherOpmode(int opmodeInt) {
062            this.opmodeInt = opmodeInt;
063        }
064    }
065
066    private static byte[] performCipherOperation(CipherOpmode opmode, byte[] input, byte[] key,
067                    byte[] initializationVector)
068                    throws IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException,
069                    NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException {
070        SecretKey secretKey = new SecretKeySpec(key, OmemoConstants.Crypto.KEYTYPE);
071        IvParameterSpec ivSpec = new IvParameterSpec(initializationVector);
072
073        Cipher cipher = Cipher.getInstance(OmemoConstants.Crypto.CIPHERMODE);
074        cipher.init(opmode.opmodeInt, secretKey, ivSpec);
075
076        byte[] ciphertext = cipher.doFinal(input);
077
078        return ciphertext;
079    }
080
081    public static byte[] decryptAesGcmNoPadding(byte[] ciphertext, byte[] key, byte[] initializationVector)
082                    throws InvalidKeyException, IllegalBlockSizeException, BadPaddingException,
083                    NoSuchAlgorithmException, NoSuchPaddingException, InvalidAlgorithmParameterException {
084        return performCipherOperation(CipherOpmode.decrypt, ciphertext, key, initializationVector);
085    }
086
087    public static byte[] encryptAesGcmNoPadding(byte[] plaintext, byte[] key, byte[] initializationVector)
088                    throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
089                    InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
090        return performCipherOperation(CipherOpmode.encrypt, plaintext, key, initializationVector);
091    }
092
093    public static byte[] encryptAesGcmNoPadding(String plaintext, byte[] key, byte[] initializationVector)
094                    throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
095                    InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
096        byte[] plaintextBytes = plaintext.getBytes(StandardCharsets.UTF_8);
097        return encryptAesGcmNoPadding(plaintextBytes, key, initializationVector);
098    }
099}