in.mtap.iincube.mongoser.codec.crypto.Psyfer.java Source code

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Here is the source code for in.mtap.iincube.mongoser.codec.crypto.Psyfer.java

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/*
 * Copyright 2015 mtap technologies
 *
 * 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 in.mtap.iincube.mongoser.codec.crypto;

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

import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

/**
 * Cipher API that uses AES for easy encryption and decryption
 */
public final class Psyfer {
    private final Cipher eCipher;
    private final Cipher deCiper;
    private final Base64 base64 = new Base64();

    Psyfer(Cipher eCipher, Cipher deCiper) {
        this.eCipher = eCipher;
        this.deCiper = deCiper;
    }

    /** @return base64 encoded format of AES encrypted form of the @param data */
    public String encrypt(String data) {
        try {
            byte[] enc = eCipher.doFinal(data.getBytes("UTF-8"));
            return base64.encodeAsString(enc);
        } catch (Exception e) {
            throw new RuntimeException("[" + e.getClass().getSimpleName() + "] @ encrypt: " + e.getMessage());
        }
    }

    /**
     * Performs Base64 decode to extract RAW bytes, and does a decipher and returns UTF-8 string
     */
    public String decrypt(String data) {
        try {
            byte[] decoded = base64.decode(data);
            return new String(deCiper.doFinal(decoded), "UTF-8");
        } catch (Exception e) {
            // temporarily suppressing all exceptions under RuntimeException.
            throw new RuntimeException("[" + e.getClass().getSimpleName() + "] @ decrypt: " + e.getMessage());
        }
    }

    public static Psyfer getInstance(String secretKey) throws NoSuchAlgorithmException,
            UnsupportedEncodingException, NoSuchPaddingException, InvalidKeyException {
        MessageDigest digest = MessageDigest.getInstance("SHA-1");
        byte[] key = digest.digest(secretKey.getBytes("UTF-8"));
        key = Arrays.copyOf(key, 16);
        SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
        Cipher eCipher = Cipher.getInstance("AES");
        Cipher deCipher = Cipher.getInstance("AES");
        eCipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
        deCipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
        return new Psyfer(eCipher, deCipher);
    }
}