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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2019 Red Hat, Inc.
 *
 * 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 org.wildfly.security.encryption;

import static org.wildfly.common.Assert.checkNotNullParam;
import static org.wildfly.security.encryption.Common.SECRET_KEY_IDENTIFIER;
import static org.wildfly.security.encryption.Common.SECRET_KEY_NAME;
import static org.wildfly.security.encryption.Common.VERSION;
import static org.wildfly.security.encryption.Common.toName;
import static org.wildfly.security.encryption.ElytronMessages.log;

import java.security.GeneralSecurityException;
import java.security.SecureRandom;
import java.util.Arrays;

import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.wildfly.common.codec.DecodeException;
import org.wildfly.common.iteration.ByteIterator;
import org.wildfly.common.iteration.CodePointIterator;


/**
 * Utility methods for operating on {@code SecretKey} instances.
 *
 * @author Darran Lofthouse
 */
public class SecretKeyUtil {

    private static final String SECRET_KEY_ALGORITHM = "AES";

    public static SecretKey generateSecretKey(int keySize) throws GeneralSecurityException {
        checkKeySize(keySize);

        SecureRandom random = new SecureRandom();
        final byte[] rawKey = new byte[keySize / 8];
        random.nextBytes(rawKey);

        SecretKey secretKey = new SecretKeySpec(rawKey, SECRET_KEY_ALGORITHM);
        Arrays.fill(rawKey, (byte) 0);

        return secretKey;
    }

    public static String exportSecretKey(final SecretKey secretKey) throws GeneralSecurityException {
        checkNotNullParam("secretKey", secretKey);

        byte[] key = secretKey.getEncoded();
        checkKeySize(key.length * 8);

        byte[] result = new byte[key.length + 5];
        // Prefix
        result[0] = 'E';
        result[1] = 'L';
        result[2] = 'Y';
        // Version (Initially only version 1 supported)
        result[3] = VERSION;
        // Type - 'K' for Key
        result[4] = SECRET_KEY_IDENTIFIER;

        System.arraycopy(key, 0, result, 5, key.length);

        return ByteIterator.ofBytes(result).base64Encode().drainToString();
    }

    public static SecretKey importSecretKey(final char[] rawData, int offset, int length) throws GeneralSecurityException {
        return importSecretKey(CodePointIterator.ofChars(checkNotNullParam("rawData", rawData), offset, length));
    }

    public static SecretKey importSecretKey(final String secretKey) throws GeneralSecurityException {
        return importSecretKey(CodePointIterator.ofString(checkNotNullParam("secretKey", secretKey)));
    }

    private static SecretKey importSecretKey(CodePointIterator codePointIterator) throws GeneralSecurityException {
        try {
            ByteIterator byteIterator = codePointIterator.base64Decode();

            byte[] prefixVersion = byteIterator.drain(5);
            if (prefixVersion.length < 4 || prefixVersion[0] != 'E' || prefixVersion[1] != 'L' || prefixVersion[2] != 'Y') {
                throw log.badKeyPrefix();
            } else if (prefixVersion[3] != VERSION) {
                throw log.unsupportedVersion(prefixVersion[3], VERSION);
            } else if (prefixVersion[4] != SECRET_KEY_IDENTIFIER) {
                throw log.unexpectedTokenType(toName((char) prefixVersion[4]), SECRET_KEY_NAME);
            }

            byte[] key = byteIterator.drain();
            checkKeySize(key.length * 8);

            return new SecretKeySpec(key, SECRET_KEY_ALGORITHM);

        } catch (DecodeException e) {
            throw log.unableToDecodeBase64Token(e);
        }
    }

    private static void checkKeySize(final int keySize) throws GeneralSecurityException {
        if (keySize != 128 && keySize != 192 && keySize != 256) {
            throw log.badKeySize();
        }
    }

}