org.mayocat.security.DefaultCipher.java Source code

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Here is the source code for org.mayocat.security.DefaultCipher.java

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/*
 * Copyright (c) 2012, Mayocat <hello@mayocat.org>
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
package org.mayocat.security;

import javax.crypto.BadPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;
import javax.inject.Inject;

import org.apache.commons.codec.binary.Base64;
import org.mayocat.configuration.SecuritySettings;
import org.slf4j.Logger;
import org.xwiki.component.annotation.Component;

import com.google.common.base.Strings;

@Component
public class DefaultCipher implements Cipher {

    @Inject
    private SecuritySettings configuration;

    @Inject
    private Logger logger;

    private enum Mode {
        CRYPT, DECRYPT
    }

    public String encrypt(String clearText) throws EncryptionException {
        return this.crypt(clearText, Mode.CRYPT);
    }

    public String decrypt(String secret) throws EncryptionException {
        return this.crypt(secret, Mode.DECRYPT);
    }

    private String crypt(String input, Mode mode) throws EncryptionException {
        if (Strings.isNullOrEmpty(this.configuration.getEncryptionKey())) {
            throw new EncryptionException("Invalid or missing cookie encryption key in configuration file. "
                    + "You MUST specify a key in order to support cookie authentication.");
        }

        try {
            byte[] in = input.getBytes();

            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            byte[] keyBytes = this.configuration.getEncryptionKey().getBytes("UTF-8");
            DESKeySpec desKeySpec = new DESKeySpec(keyBytes);
            SecretKey key = keyFactory.generateSecret(desKeySpec);

            javax.crypto.Cipher cipher = javax.crypto.Cipher.getInstance("DES/ECB/PKCS5Padding");
            IvParameterSpec spec = null;
            if (cipher.getParameters() != null) {
                spec = cipher.getParameters().getParameterSpec(IvParameterSpec.class);
            }

            switch (mode) {
            case CRYPT:
            default:
                if (spec != null) {
                    cipher.init(javax.crypto.Cipher.ENCRYPT_MODE, key, spec);
                } else {
                    cipher.init(javax.crypto.Cipher.ENCRYPT_MODE, key);
                }
                byte[] encrypted = cipher.doFinal(in);
                return new String(Base64.encodeBase64(encrypted));
            case DECRYPT:
                if (spec != null) {
                    cipher.init(javax.crypto.Cipher.DECRYPT_MODE, key, spec);
                } else {
                    cipher.init(javax.crypto.Cipher.DECRYPT_MODE, key);
                }
                byte[] decrypted = cipher.doFinal(Base64.decodeBase64(in));
                return new String(decrypted);
            }

        } catch (BadPaddingException e) {
            this.logger.warn("Bad padding when attempting to decipher cookies. Key changed ?");
            throw new EncryptionException(e);
        } catch (Exception e) {
            this.logger.error("Fail to perform cookie crypt or decrypt operation", e);
            throw new EncryptionException(e);
        }
    }
}