com.springcryptoutils.core.cipher.asymmetric.Base64EncodedCiphererWithChooserByKeyIdImpl.java Source code

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Here is the source code for com.springcryptoutils.core.cipher.asymmetric.Base64EncodedCiphererWithChooserByKeyIdImpl.java

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/*
 * Copyright 2012 Mirko Caserta
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this software 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 com.springcryptoutils.core.cipher.asymmetric;

import java.security.Key;
import java.util.Map;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;

import com.springcryptoutils.core.cipher.Mode;

/**
 * The default implementation for performing asymmetric encryption/decryption
 * with base64 encoded strings and keys which are mapped with a logical name.
 *
 * @author Mirko Caserta (mirko.caserta@gmail.com)
 */
public class Base64EncodedCiphererWithChooserByKeyIdImpl implements Base64EncodedCiphererWithChooserByKeyId {

    private String algorithm = "RSA";
    private String charsetName = "UTF-8";
    private String provider;
    private Mode mode;

    private Map<String, Key> keyMap;

    /**
     * The asymmetric key algorithm. The default is RSA.
     *
     * @param algorithm the asymmetric key algorithm
     */
    public void setAlgorithm(String algorithm) {
        this.algorithm = algorithm;
    }

    /**
     * The charset used when a message must be converted into a raw byte array.
     * Default is UTF-8.
     *
     * @param charsetName the charset name
     */
    public void setCharsetName(String charsetName) {
        this.charsetName = charsetName;
    }

    /**
     * Sets the provider name of the specific implementation requested (e.g.,
     * "BC" for BouncyCastle, "SunJCE" for the default Sun JCE provider).
     *
     * @param provider the provider to set
     */
    public void setProvider(String provider) {
        this.provider = provider;
    }

    /**
     * Sets the encryption/decryption mode.
     *
     * @param mode the encryption/decryption mode
     */
    public void setMode(Mode mode) {
        this.mode = mode;
    }

    /**
     * Sets the map of keys. The map key is a string representing the logical
     * name of the key (the keyId).
     *
     * @param keyMap the key map
     */
    public void setKeyMap(Map<String, Key> keyMap) {
        this.keyMap = keyMap;
    }

    /**
     * Encrypts/decrypts a message based on the underlying mode of operation.
     *
     * @param keyId the key id
     * @param message if in encryption mode, the clear-text message, otherwise
     *        the base64 encoded message to decrypt
     * @return if in encryption mode, the base64 encoded encrypted message,
     *         otherwise the decrypted message
     * @throws AsymmetricEncryptionException on runtime errors
     * @see #setMode(Mode)
     */
    public String encrypt(String keyId, String message) {
        final Key key = keyMap.get(keyId);

        if (key == null) {
            throw new AsymmetricEncryptionException("key not found: keyId=" + keyId);
        }

        try {
            final Cipher cipher = (((provider == null) || (provider.length() == 0)) ? Cipher.getInstance(algorithm)
                    : Cipher.getInstance(algorithm, provider));
            switch (mode) {
            case ENCRYPT:
                final byte[] messageAsByteArray = message.getBytes(charsetName);
                cipher.init(Cipher.ENCRYPT_MODE, key);
                return Base64.encodeBase64String(cipher.doFinal(messageAsByteArray));
            case DECRYPT:
                final byte[] encryptedMessage = Base64.decodeBase64(message);
                cipher.init(Cipher.DECRYPT_MODE, key);
                return new String(cipher.doFinal(encryptedMessage), charsetName);
            default:
                return null;
            }
        } catch (Exception e) {
            throw new AsymmetricEncryptionException("error encrypting/decrypting message; mode=" + mode, e);
        }
    }

}