Article directory
- File encryption and decryption
-
- encrypt documents
- File decryption
- Folder encryption and decryption
-
- Encrypt files
- Decrypt files
File encryption and decryption
Encryption and decryption using AES algorithm
AEC is the abbreviation of Advanced Encryption Standard. It is a symmetric key encryption algorithm commonly used for data encryption and privacy protection.
package com.sin.utils;
import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
/**
* @createTime 2023/10/18 11:24
* @createAuthor SIN
* @use file encryption and decryption
*/
public class DocumentEncryptionUtil {<!-- -->
// File encryption method
private static final String ALGORITHM = "AES";
/**
* encrypt documents
* @param secretKey file encryption key
* @param sourceFilePath needs to encrypt the file address
* @param destinationFilePath encrypted file address
*/
public static void encryptFile(String secretKey,String sourceFilePath, String destinationFilePath) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IOException {<!-- -->
// Generate a secret key using the key string
SecretKey secretKeySpec = new SecretKeySpec(secretKey.getBytes(), ALGORITHM);
// Get an instance of the AES encryption algorithm
Cipher cipher = Cipher.getInstance(ALGORITHM);
// Initialize the cipher cipher using the secret key, set to encryption mode
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
// Get the source file path
Path sourcePath = Paths.get(sourceFilePath);
// Get the target encrypted file path
Path destinationPath = Paths.get(destinationFilePath);
//Create an input stream and read the source file
try (InputStream inputStream = Files.newInputStream(sourcePath);
//Create an output stream and write the encrypted file
OutputStream outputStream = Files.newOutputStream(destinationPath);
// Create a cipher output stream, connect to the output stream, and encrypt using the password cipher
CipherOutputStream cipherOutputStream = new CipherOutputStream(outputStream, cipher)) {<!-- -->
// buffer size
byte[] buffer = new byte[4096];
int bytesRead;
//Read the source file content into the buffer
while ((bytesRead = inputStream.read(buffer)) != -1) {<!-- -->
//Write the encrypted data to the encrypted file
cipherOutputStream.write(buffer, 0, bytesRead);
}
}
}
/**
*File decryption
* @param secretKey file decryption key
* @param sourceFilePath The file address to be decrypted
* @param destinationFilePath decrypted file address
*/
public static void decryptFile(String secretKey,String sourceFilePath, String destinationFilePath) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IOException {<!-- -->
SecretKey secretKeySpec = new SecretKeySpec(secretKey.getBytes(), ALGORITHM); // Generate a secret key using the key string
Cipher cipher = Cipher.getInstance(ALGORITHM); // Get an instance of the AES encryption algorithm
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec); // Initialize the password cipher using the secret key and set it to decryption mode
Path sourcePath = Paths.get(sourceFilePath); // Get the source encrypted file path
Path destinationPath = Paths.get(destinationFilePath); // Get the target decrypted file path
try (InputStream inputStream = Files.newInputStream(sourcePath); // Create an input stream and read the encrypted file
OutputStream outputStream = Files.newOutputStream(destinationPath); // Create an output stream and write the decrypted file
CipherInputStream cipherInputStream = new CipherInputStream(inputStream, cipher)) {<!-- --> // Create a cipher input stream, connect to the input stream, and use the password cipher to decrypt
byte[] buffer = new byte[4096]; // buffer size
int bytesRead;
while ((bytesRead = cipherInputStream.read(buffer)) != -1) {<!-- --> // Read the contents of the encrypted file into the buffer
outputStream.write(buffer, 0, bytesRead); //Write the decrypted data to the decrypted file
}
}
}
}
File encryption
The target file is the content
package com.sin.utils.test;
import com.sin.utils.DocumentEncryptionUtil;
import org.junit.Test;
import javax.crypto.NoSuchPaddingException;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
/**
* @createTime 2023/10/18 11:28
* @createAuthor SIN
* @use
*/
public class DocumentEncryptionUtilTest {<!-- -->
/**
* encrypt documents
*/
@Test
public void encryptFileTest(){<!-- -->
try {<!-- -->
DocumentEncryptionUtil.encryptFile("SIN-80238023-@@@","D:/FileEncryptionUtil.txt","D:/Demo/FileEncryptionUtil.txt");
} catch (NoSuchAlgorithmException e) {<!-- -->
throw new RuntimeException(e);
} catch (NoSuchPaddingException e) {<!-- -->
throw new RuntimeException(e);
} catch (InvalidKeyException e) {<!-- -->
throw new RuntimeException(e);
} catch (IOException e) {<!-- -->
throw new RuntimeException(e);
}
}
encrypted file
File decryption
/**
*File decryption
*/
@Test
public void decryptFileTest(){<!-- -->
try {<!-- -->
DocumentEncryptionUtil.decryptFile("SIN-80238023-@@@","D:/Demo/FileEncryptionUtil.txt","D:/Demo/FileEncryptionUtil1.txt");
} catch (NoSuchAlgorithmException e) {<!-- -->
throw new RuntimeException(e);
} catch (NoSuchPaddingException e) {<!-- -->
throw new RuntimeException(e);
} catch (InvalidKeyException e) {<!-- -->
throw new RuntimeException(e);
} catch (IOException e) {<!-- -->
throw new RuntimeException(e);
}
}
Decrypted file
Folder encryption and decryption
package com.sin.utils;
import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
/**
* @createTime 2023/10/19 9:20
* @createAuthor SIN
* @use folder encryption and decryption
*/
public class FileEncryptionUtil {<!-- -->
//AES is the abbreviation of Advanced Encryption Standard. It is a symmetric key encryption algorithm commonly used for data encryption and privacy protection.
private static final String ALGORITHM = "AES";
/**
* Remove file name extension
* @param fileName the file to be operated on
* @return
*/
private static String removeExtension(String fileName) {<!-- -->
// Find the last point of the file
int dotIndex = fileName.lastIndexOf(".");
// Ensure that the points are not the first and last characters of the file name
if (dotIndex > 0 & amp; & amp; dotIndex < fileName.length() - 1) {<!-- -->
// Return a valid extension
return fileName.substring(0, dotIndex);
}
//Return to source file
return fileName;
}
/**
* Folder encryption
* @param secretKey folder encryption key
* @param sourceFilePath The folder that needs to be encrypted
* @param destinationFilePath encrypted folder address
*/
public static void encryptFile(String secretKey,String sourceFilePath, String destinationFilePath) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IOException {<!-- -->
// Generate a secret key using the key string
SecretKey secretKeySpec = new SecretKeySpec(secretKey.getBytes(), ALGORITHM);
// Get an instance of the AES encryption algorithm
Cipher cipher = Cipher.getInstance(ALGORITHM);
// Initialize the cipher cipher using the secret key, set to encryption mode
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
// Get the source file or folder path
Path sourcePath = Paths.get(sourceFilePath);
// Get the target encrypted file or folder path
Path destinationPath = Paths.get(destinationFilePath);
if (Files.isDirectory(sourcePath) & amp; & amp; !Files.exists(destinationPath)) {<!-- -->
//Create target folder
Files.createDirectories(destinationPath);
// Traverse the source folder
try (DirectoryStream<Path> directoryStream = Files.newDirectoryStream(sourcePath)) {<!-- -->
for (Path filePath : directoryStream) {<!-- -->
//Encrypted file name
String encryptedFileName = filePath.getFileName().toString() + ".enc";
//Encrypted file path
String encryptedFilePath = destinationPath.resolve(encryptedFileName).toString();
// Call the encryption method recursively to process sub-files or sub-folders
encryptFile(secretKey,filePath.toString(), encryptedFilePath);
}
}
} else if (Files.isRegularFile(sourcePath)) {<!-- -->
//Create an input stream and read the source file
try (InputStream inputStream = Files.newInputStream(sourcePath);
//Create an output stream and write the encrypted file
OutputStream outputStream = Files.newOutputStream(destinationPath);
//Create a cipher output stream, connect to the output stream, and encrypt using the password cipher
CipherOutputStream cipherOutputStream = new CipherOutputStream(outputStream, cipher)) {<!-- -->
// buffer size
byte[] buffer = new byte[4096];
int bytesRead;
//Read the source file content into the buffer
while ((bytesRead = inputStream.read(buffer)) != -1) {<!-- -->
//Write the encrypted data to the encrypted file
cipherOutputStream.write(buffer, 0, bytesRead);
}
}
}
}
/**
*
* @param secretKey folder decryption key
* @param sourceFilePath The folder to be decrypted
* @param destinationFilePath decrypted folder address
*/
public static void decryptFile(String secretKey,String sourceFilePath, String destinationFilePath) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IOException {<!-- -->
SecretKey secretKeySpec = new SecretKeySpec(secretKey.getBytes(), ALGORITHM); // Generate a secret key using the key string
Cipher cipher = Cipher.getInstance(ALGORITHM); // Get an instance of the AES encryption algorithm
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec); // Initialize the password cipher using the secret key and set it to decryption mode
Path sourcePath = Paths.get(sourceFilePath); // Get the source encrypted file or folder path
Path destinationPath = Paths.get(destinationFilePath); // Get the target decrypted file or folder path
if (Files.isDirectory(sourcePath) & amp; & amp; !Files.exists(destinationPath)) {<!-- -->
Files.createDirectories(destinationPath); // Create destination folder
try (DirectoryStream<Path> directoryStream = Files.newDirectoryStream(sourcePath)) {<!-- --> // Traverse the source folder
for (Path filePath : directoryStream) {<!-- -->
String decryptedFileName = removeExtension(filePath.getFileName().toString()); // Remove the extension of the file name
String decryptedFilePath = destinationPath.resolve(decryptedFileName).toString(); // Decrypted file path
decryptFile(secretKey,filePath.toString(), decryptedFilePath); // Recursively call the decryption method to process sub-files or sub-folders
}
}
} else if (Files.isRegularFile(sourcePath)) {<!-- -->
try (InputStream inputStream = Files.newInputStream(sourcePath); // Create an input stream and read the encrypted file
OutputStream outputStream = Files.newOutputStream(destinationPath); // Create an output stream and write the decrypted file
CipherInputStream cipherInputStream = new CipherInputStream(inputStream, cipher)) {<!-- --> // Create a cipher input stream, connect to the input stream, and use the password cipher to decrypt
byte[] buffer = new byte[4096]; // buffer size
int bytesRead;
while ((bytesRead = cipherInputStream.read(buffer)) != -1) {<!-- --> // Read the contents of the encrypted file into the buffer
outputStream.write(buffer, 0, bytesRead); //Write the decrypted data to the decrypted file
}
}
}
}
}
Files that need to be encrypted
Encrypted files
package com.sin.utils.test;
import com.sin.utils.FileEncryptionUtil;
import org.junit.Test;
import javax.crypto.NoSuchPaddingException;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
/**
* @createTime 2023/10/19 9:32
* @createAuthor SIN
* @use test folder encryption and decryption
*/
public class FileEncryptionUtilTest {<!-- -->
/**
* Encrypted files
*/
@Test
public void encryptFileTest(){<!-- -->
try {<!-- -->
FileEncryptionUtil.encryptFile("sin-80238023-@@@","D:/Demo","D:/Demo1");
} catch (NoSuchAlgorithmException e) {<!-- -->
throw new RuntimeException(e);
} catch (NoSuchPaddingException e) {<!-- -->
throw new RuntimeException(e);
} catch (InvalidKeyException e) {<!-- -->
throw new RuntimeException(e);
} catch (IOException e) {<!-- -->
throw new RuntimeException(e);
}
}
encrypted file
Decrypt files
/**
* Decrypt files
*/
@Test
public void decryptFile(){<!-- -->
try {<!-- -->
FileEncryptionUtil.decryptFile("sin-80238023-@@@","D:/Demo1","D:/Demo2");
} catch (NoSuchAlgorithmException e) {<!-- -->
throw new RuntimeException(e);
} catch (NoSuchPaddingException e) {<!-- -->
throw new RuntimeException(e);
} catch (InvalidKeyException e) {<!-- -->
throw new RuntimeException(e);
} catch (IOException e) {<!-- -->
throw new RuntimeException(e);
}
}
Decrypted file
