Java Technologies: Encrypt decrypt files example

Click here to download eclipse supported ZIP file

This is input.properties properties file and these properties are used in the application.


plain.files.location=/inputFiles/

key.file.location=/keyFile/

encrypted.files.location=/encryptedFiles/

decrypted.files.location=/decryptedFiles/

lastDaysToUpdate = 1


ELEMENT_VALUES=property

This is CryptoUtils.java file having the source code to execute business logic.

 
    
package com.cv.java.enc;



import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.security.Key;

import java.security.NoSuchAlgorithmException;

import java.security.SecureRandom;

import java.security.Security;

import javax.crypto.Cipher;

import javax.crypto.CipherOutputStream;

import javax.crypto.KeyGenerator;

import org.apache.log4j.Logger;

import sun.misc.BASE64Decoder;

import sun.misc.BASE64Encoder;



/**

 * @author Chandra Vardhan

 */

public class CryptoUtils {

  private static final Logger LOGGER = Logger.getLogger(CryptoUtils.class);

  public static String process(final String input, final String algorithm, final String actionMode) throws Exception {

    LOGGER.info("IN process( - - -)");

    int mode;

    // add a BouncyCastle provider

    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

    // mode

    if (actionMode.equals("enc")) {

      mode = Cipher.ENCRYPT_MODE;

    } else if (actionMode.equals("dec")) {

      mode = Cipher.DECRYPT_MODE;

    } else {

      return null;

    }



    // Generate a key

    Key key = null;

    ByteArrayInputStream bis = null;

    CipherOutputStream cos = null;

    ObjectInputStream secKeyFile = null;

    ByteArrayOutputStream bos = null;

    try {

      String keyFileLocation = ReadFiles.getKeyFileLocation();

      if (keyFileLocation != null) {

        File file = new File(keyFileLocation);

        if(!file.exists()) {

          file.mkdirs();

        }        

      }

      File file = new File(keyFileLocation+ "crypto_key.ser");

      if (file != null) {

        if (!file.exists()) {

          ObjectOutputStream keyFile = null;

          try {

            KeyGenerator keygen = KeyGenerator.getInstance(algorithm, "BC");

            keygen.init(new SecureRandom());

            key = keygen.generateKey();

            keyFile = new ObjectOutputStream(new FileOutputStream(file));

            keyFile.writeObject(key);

          } catch (NoSuchAlgorithmException ex) {

            LOGGER.error(algorithm + " key generator not found.");

            System.exit(0);

          } catch (IOException ex) {

            LOGGER.error("Error saving key.");

            System.exit(0);

          } finally {

            if (keyFile != null) {

              keyFile.close();

            }



          }

        }

      }

      // Does a cryptoKey.ser file exist?

      secKeyFile = new ObjectInputStream(new FileInputStream(file));

      key = (Key) secKeyFile.readObject();

      Cipher cipher = Cipher.getInstance(algorithm + "/ECB/PKCS5Padding", "BC");

      cipher.init(mode, key);

      bos = new ByteArrayOutputStream();



      if (mode == Cipher.DECRYPT_MODE) {

        BASE64Decoder decoder = new BASE64Decoder();

        bis = new ByteArrayInputStream(decoder.decodeBuffer(input));

      } else {

        bis = new ByteArrayInputStream(input.getBytes());

      }

      cos = new CipherOutputStream(bos, cipher);

      int length = 0;

      byte[] buffer = new byte[8192];

      while ((length = bis.read(buffer)) != -1) {

        cos.write(buffer, 0, length);

      }



      if (mode == Cipher.ENCRYPT_MODE) {

        BASE64Encoder encoder = new BASE64Encoder();

        return encoder.encode(bos.toByteArray());

      } else {

        return bos.toString();

      }

    } catch (Exception e) {

      e.printStackTrace();

      LOGGER.error("Error reading key.");

      System.exit(0);

    } finally {

      if (bis != null) {

        bis.close();

      }

      if (bos != null) {

        bos.close();

      }

      if (cos != null) {

        cos.close();

      }

      if (secKeyFile != null) {

        secKeyFile.close();

      }

    }

    LOGGER.info("OUT process( - - -)");

    return null;



  }

}

This is MainDecrypt.java file having the source code to execute business logic.

 
    
package com.cv.java.enc;





import java.io.BufferedReader;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.List;



import org.apache.log4j.Logger;



/**

 * @author Chandra Vardhan

 */



public class MainDecrypt {



  private static final Logger LOGGER = Logger.getLogger(MainDecrypt.class);



  private static final String REG_EX1 = "##$#";



  private static final String REG_EX2 = "$$#$";



  public static void main(String[] args) {

    

    LOGGER.info("IN main(-)");

    ReadFiles readFiles = new ReadFiles();

    String encFileDirectory = ReadFiles.getEncFileDirectory();

    File encFile =  new File(encFileDirectory);

    if(encFile != null) {

      if(!encFile.exists()) {

        encFile.mkdirs();

      }

    }

    List<String> latestDaysUpdatedFiles = readFiles.getLatestDaysUpdatedFiles(

        new File(encFileDirectory), Integer.parseInt(ReadFiles.getLastDaysToUpdate()));

    LOGGER.info("Size of the files for decryption : : "+ latestDaysUpdatedFiles.size());

    for (String latestUpdatedFile : latestDaysUpdatedFiles) {

      File file = new File(latestUpdatedFile);

      BufferedReader br = null;

      PrintWriter pw = null;

      try {

        StringBuffer sb = new StringBuffer();

        br = new BufferedReader(new FileReader(file));

        String line = "";

        do {

          sb.append(line);

          sb.append("\n");

        } while ((line = br.readLine()) != null);



        String plainText = CryptoUtils.process(sb.toString(), "AES", "dec");

        if (plainText != null) {



          plainText = plainText.substring(plainText.lastIndexOf(REG_EX1) + REG_EX1.length(),

              plainText.indexOf(REG_EX2));

        }

        String plainFileDirectory = ReadFiles.getDecFileDirectory();

        File file2 =  new File(plainFileDirectory);

        if(file2 != null) {

          if(!file2.exists()) {

            file2.mkdirs();

          }

        }

        

        pw = new PrintWriter(new FileWriter(plainFileDirectory+ "\\" + file.getName()));

        

        pw.write(RegExUtils.modifyInformation(plainText));

        pw.flush();

      } // end try

      catch (Exception e) {

        LOGGER.info("Problem while decrypting, file name is ::" + file.getAbsolutePath());

        e.printStackTrace();

      } // end catch

      finally {

        if (br != null) {

          try {

            br.close();

          } catch (IOException e) {

            e.printStackTrace();

          }

        }

        if (pw != null) {

          pw.close();

        }

      }

      LOGGER.info("OUT main(-)");

    }

  }



  

}

This is MainEncrypt.java file having the source code to execute business logic.

 
    
package com.cv.java.enc;



import java.io.BufferedReader;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.ArrayList;

import java.util.List;



import org.apache.log4j.Logger;



/**

 * @author Chandra Vardhan

 */



public class MainEncrypt {



  private static final Logger LOGGER = Logger.getLogger(MainEncrypt.class);



  private static final String START_STRING = "#$##Starting##$#";



  private static final String END_STRING = "$$#$Ending$#$$";



  public static void main(String[] args) {

    LOGGER.info("IN main(-");

    ReadFiles readFiles = new ReadFiles();

    String plainFileDirectory = ReadFiles.getPlainFileDirectory();

    File plainFile = new File(plainFileDirectory);

    if (plainFile != null) {

      if (!plainFile.exists()) {

        plainFile.mkdirs();

      }

    }



    List<String> resultFileList = readFiles.getResultFileList();

    if (resultFileList != null && !resultFileList.isEmpty()) {

      readFiles.setResultFileList(new ArrayList<String>());

    }

    List<String> latestDaysUpdatedFiles = readFiles.getLatestDaysUpdatedFiles(new File(plainFileDirectory),

        Integer.parseInt(ReadFiles.getLastDaysToUpdate()));

    LOGGER.info("Files count for encryption : : " + latestDaysUpdatedFiles.size());

    for (String latestUpdatedFile : latestDaysUpdatedFiles) {

      File file = new File(latestUpdatedFile);

      BufferedReader br = null;

      PrintWriter pw = null;

      try {

        StringBuffer sb = new StringBuffer();

        br = new BufferedReader(new FileReader(file));

        String line = "";

        sb.append(START_STRING);

        sb.append("\n");

        while ((line = br.readLine()) != null) {

          sb.append(line);

          sb.append("\n");

        }

        String palinText = sb.toString();

        String result = null;

        if (palinText.contains("http") || palinText.contains("xmlns") ||palinText.contains("property")) {

          sb.append(END_STRING);

          sb.append("\n");

          sb.append(END_STRING);

          sb.append("\n");

          sb.append(END_STRING);

          sb.append("\n");

          result = CryptoUtils.process(sb.toString(), "AES", "enc");

        } else {

          if (palinText != null) {

            String res = palinText.substring(START_STRING.length(), palinText.length());

            result = res;

          }

        }

        String encFileDirectory = ReadFiles.getEncFileDirectory();

        File encFile = new File(encFileDirectory);

        if (encFile != null) {

          if (!encFile.exists()) {

            encFile.mkdirs();

          }

        }



        pw = new PrintWriter(new FileWriter(encFile+"/"+file.getName()));

        pw.write(result);

        pw.flush();

      } // end try

      catch (Exception e) {

        e.printStackTrace();

      } // end catch

      finally {

        if (br != null) {

          try {

            br.close();

          } catch (IOException e) {

            e.printStackTrace();

          }

        }

        if (pw != null) {

          pw.close();

        }

      }

    }



  }

}

This is ReadFiles.java file having the source code to execute business logic.

 
    
package com.cv.java.enc;



import java.io.File;

import java.util.ArrayList;

import java.util.Calendar;

import java.util.Date;

import java.util.List;

import java.util.Properties;

import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;



/**

 * @author Chandra Vardhan

 */



public class ReadFiles {

  

  private static final Logger LOGGER = Logger.getLogger(ReadFiles.class);



  static Properties readPropertiesFile = new Properties();

  private static String plainFileDirectory = null;

  private static String encFileDirectory = null;

  private static String decFileDirectory = null;

  private static String lastDaysToUpdate = null;

  private static String keyFileLocation = null;

  private static String tagValues = "";

  private static final String USER_DIR = System.getProperty("user.dir");

  private List<String> resultFileList = new ArrayList<String>();



  static {



    readPropertiesFile = readPropertiesFile();

    setValues(readPropertiesFile);



  }



  private static void setValues(Properties readPropertiesFile2) {



    if (readPropertiesFile2 != null) {

      plainFileDirectory = readPropertiesFile2.getProperty("plain.files.location");

      encFileDirectory = readPropertiesFile2.getProperty("encrypted.files.location");

      decFileDirectory = readPropertiesFile2.getProperty("decrypted.files.location");

      lastDaysToUpdate = readPropertiesFile2.getProperty("lastDaysToUpdate");

      keyFileLocation = readPropertiesFile2.getProperty("key.file.location");

      tagValues = readPropertiesFile2.getProperty("ELEMENT_VALUES");

      }



  }



  private static Properties readPropertiesFile() {

    Properties props = new Properties();

    try {

      props.load(ReadFiles.class.getClassLoader().getResourceAsStream("input.properties"));

    } catch (Exception e) {

      LOGGER.info("Problem while reading properties file!!!");

    }

    return props;

  }



  



  public List<String> getLatestDaysUpdatedFiles(final File directory, final int lastDays) {



    if (directory != null) {

      File[] listFiles = directory.listFiles();

      if (listFiles != null) {

        for (File file : listFiles) {

          if (file != null) {

            if (file.isDirectory()) {

              getLatestDaysUpdatedFiles(file, lastDays);

            } else {

              Calendar calendar = Calendar.getInstance();

              calendar.add(Calendar.DAY_OF_MONTH, -lastDays);

              long diffInDays = getDateDiff(calendar.getTime(), new Date(file.lastModified()), TimeUnit.DAYS);

              if (Math.abs(diffInDays) < 1) {

                resultFileList.add(file.getAbsolutePath());

              }

            }



          }



        }

      }

    }

    return resultFileList;

  }



  public static long getDateDiff(Date date1, Date date2, TimeUnit timeUnit) {

    long diffInMillies = date2.getTime() - date1.getTime();

    return timeUnit.convert(diffInMillies, TimeUnit.MILLISECONDS);

  }



  public static String getLastDaysToUpdate() {

    return lastDaysToUpdate;

  }



  public static void setLastDaysToUpdate(String lastDaysToUpdate) {

    ReadFiles.lastDaysToUpdate = lastDaysToUpdate;

  }



  public static String getPlainFileDirectory() {

    return USER_DIR+plainFileDirectory;

  }



  public static void setPlainFileDirectory(String plainFileDirectory) {

    ReadFiles.plainFileDirectory = plainFileDirectory;

  }



  public static String getEncFileDirectory() {

    return USER_DIR+encFileDirectory;

  }



  public static void setEncFileDirectory(String encFileDirectory) {

    ReadFiles.encFileDirectory = encFileDirectory;

  }



  public static String getDecFileDirectory() {

    return USER_DIR+decFileDirectory;

  }



  public static void setDecFileDirectory(String decFileDirectory) {

    ReadFiles.decFileDirectory = decFileDirectory;

  }



  public static String getKeyFileLocation() {

    return USER_DIR+keyFileLocation;

  }



  public static void setKeyFileLocation(String keyFileLocation) {

    ReadFiles.keyFileLocation = keyFileLocation;

  }



  public static String getTagValues() {

    return tagValues;

  }



  public static void setTagValues(String tagValues) {

    ReadFiles.tagValues = tagValues;

  }



  public List<String> getResultFileList() {

    return resultFileList;

  }



  public void setResultFileList(List<String> resultFileList) {

    this.resultFileList = resultFileList;

  }



}

This is RegExUtils.java file having the source code to execute business logic.

 
    
package com.cv.java.enc;





import java.util.HashMap;

import java.util.Map;

import java.util.Map.Entry;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import org.apache.log4j.Logger;



/**

 * @author Chandra Vardhan

 */

public class RegExUtils {

  private static final Logger LOGGER = Logger.getLogger(RegExUtils.class);

  private static final String SPECIFIC_REGEX = "(\\b(?:\\d[ -xX]*?){16}\\b)";

  private static final String GENERIC_REGEX = "(\\b\\d{16}\\b)";

  private static Map<String, Pattern> Patterns = new HashMap<String, Pattern>();

  static {

    preparePatterns();

  }

  

  private static void preparePatterns() {

    

    LOGGER.debug("IN preparePatterns()");

    

    String TagValues = ReadFiles.getTagValues();

    if (TagValues != null) {

      String[] values = TagValues.split(",");

      for (String temp : values) {

        final String regEx = "<" + temp + ">" + SPECIFIC_REGEX + "</" + temp + ">";

        final Pattern pattern = Pattern.compile(regEx);

        Patterns.put(temp, pattern);

      }

      final Pattern pattern = Pattern.compile(GENERIC_REGEX);

      Patterns.put("generic", pattern);



    }

    LOGGER.debug("OUT preparePatterns()");



  }

  public static String modifyInformation(String plainText) {

    LOGGER.debug("IN modifyInformation(-)");

    String res = plainText;

    if (plainText != null) {

      for (Entry<String, Pattern> entry : Patterns.entrySet()) {

        final Pattern pattern = entry.getValue();

        Matcher matcher = pattern.matcher(plainText);

        try {

        if(matcher != null && matcher.find()) {

          String grp1 = matcher.group(1);

          if(grp1 != null) {

            res = res.replaceAll(grp1, "XXXXXXXXXXXX");

          }

          

        }

        } catch(Exception e) {

          e.printStackTrace();

        }

      }

    }

    LOGGER.debug("OUT modifyInformation(-)");

    return res;

  }

  public static Map<String, Pattern> getPatterns() {

    return Patterns;

  }



  public static void setPatterns(Map<String, Pattern> Patterns) {

    RegExUtils.Patterns = Patterns;

  }

  

  

  

}

This is pom.xml file having the entries of dependency jars and information to build the application .

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.cv.java.enc</groupId>
	<artifactId>EncryptDecryptFiles</artifactId>
	<version>1.0</version>


	<dependencies>
		
		<dependency>
			<groupId>com.sun.jersey</groupId>
			<artifactId>jersey-bundle</artifactId>
			<version>1.11</version>
		</dependency>
		<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>1.2.17</version>
		</dependency>
		
		<dependency>
			<groupId>org.bouncycastle</groupId>
			<artifactId>bcprov-jdk16</artifactId>
			<version>1.46</version>
		</dependency>

	</dependencies>
	<build>
		<pluginManagement>
			<plugins>
				<plugin>
					<groupId>org.apache.maven.plugins</groupId>
					<artifactId>maven-compiler-plugin</artifactId>
					<version>3.1</version>
					<configuration>
						<source>1.8</source>
						<target>1.8</target>
					</configuration>
				</plugin>

			</plugins>
		</pluginManagement>
		<finalName>EncryptDecryptFiles</finalName>
	</build>
</project>

This is log4j.properties file having the entries for logging the information into the console/file.

#By default enabling Console appender
# Root logger option
log4j.rootLogger=INFO, stdout

# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%-5p [%c]:%L -->> %m%n

# Redirect log messages to a log file
#log4j.appender.file=org.apache.log4j.RollingFileAppender
#log4j.appender.file.File=C:\servlet-application.log
#log4j.appender.file.MaxFileSize=5MB
#log4j.appender.file.MaxBackupIndex=10
#log4j.appender.file.layout=org.apache.log4j.PatternLayout
#log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

Java Technologies

Encrypt decrypt files example

Click here to download eclipse supported ZIP file

This is input.properties properties file and these properties are used in the application.

This is CryptoUtils.java file having the source code to execute business logic.

This is MainDecrypt.java file having the source code to execute business logic.

This is MainEncrypt.java file having the source code to execute business logic.

This is ReadFiles.java file having the source code to execute business logic.

This is RegExUtils.java file having the source code to execute business logic.

This is pom.xml file having the entries of dependency jars and information to build the application .

This is log4j.properties file having the entries for logging the information into the console/file.

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