Need help implementing CipherInputStream and CipherOutputStream

Question

I'm having some issues converting FileInputStream and FileOutputStream into CipherInputStream and CipherOutputStream for my 3DES encryption algorithm. Could someone direct me on the right path on how to do it? I end up getting the error: "CipherInputStream cannot be resolved to a type". Sorry if this is obvious.

// author Alexander Matheakis
public static void main(String[] args) throws Exception {


    // file to be encrypted
    FileInputStream inputFile = new FileInputStream("plainfile.txt");

    // encrypted file
    FileOutputStream outputFile = new FileOutputStream("C:\\Users\\islan\\OneDrive\\Documents\\Encryptor\\plainfile.des");

    // password to encrypt the file
    String passKey = "tkfhkggovubm";


    byte[] salt = new byte[8];
    SecureRandom r = new SecureRandom();    
    r.nextBytes(salt);
    PBEKeySpec pbeKeySpec = new PBEKeySpec(passKey.toCharArray());
    SecretKeyFactory secretKeyFactory = SecretKeyFactory
            .getInstance("PBEWithSHA1AndDESede");
    SecretKey secretKey = secretKeyFactory.generateSecret(pbeKeySpec);


    PBEParameterSpec pbeParameterSpec = new PBEParameterSpec(salt, 99999);
    Cipher cipher = Cipher.getInstance("PBEWithSHA1AndDESede"); 
    cipher.init(Cipher.ENCRYPT_MODE, secretKey, pbeParameterSpec);
    outputFile.write(salt);

    byte[] input = new byte[64];
    int bytesRead;
    while ((bytesRead = inputFile.read(input)) != -1) {
        byte[] output = cipher.update(input, 0, bytesRead);
        if (output != null)
            outputFile.write(output);
    }

    byte[] output = cipher.doFinal();
    if (output != null)
        outputFile.write(output);

    inputFile.close();
    outputFile.flush();
    outputFile.close();

// author Alexander Matheakis

Answer 1

This works for me:

public class Cypher {

    // password to encrypt the file
    private static final String passKey = "tkfhkggovubm";

    public static void main(String[] args) throws Exception {

        try (FileInputStream inputFile = new FileInputStream("plainfile.txt");
                FileOutputStream outputFile = new FileOutputStream("plainfile.des");) {

            byte[] salt = new byte[8];
            SecureRandom r = new SecureRandom();
            r.nextBytes(salt);

            outputFile.write(salt);

            PBEKeySpec pbeKeySpec = new PBEKeySpec(passKey.toCharArray());
            SecretKeyFactory secretKeyFactory = SecretKeyFactory
                    .getInstance("PBEWithSHA1AndDESede");
            SecretKey secretKey = secretKeyFactory.generateSecret(pbeKeySpec);

            PBEParameterSpec pbeParameterSpec = new PBEParameterSpec(salt, 99999);
            Cipher cipher = Cipher.getInstance("PBEWithSHA1AndDESede");
            cipher.init(Cipher.ENCRYPT_MODE, secretKey, pbeParameterSpec);

            try (CipherOutputStream cis = new CipherOutputStream(outputFile, cipher);) {
                IOUtils.copy(inputFile, cis);
            }
        }

        try (FileInputStream fis = new FileInputStream("plainfile.des");
                FileOutputStream outputFile = new FileOutputStream("plainfile.txt2");) {
            byte[] salt = new byte[8];
            int saltBytes = fis.read(salt);
            if (saltBytes!=salt.length)
                throw new Exception("Huh???");

            PBEKeySpec pbeKeySpec = new PBEKeySpec(passKey.toCharArray());
            SecretKeyFactory secretKeyFactory = SecretKeyFactory
                    .getInstance("PBEWithSHA1AndDESede");
            SecretKey secretKey = secretKeyFactory.generateSecret(pbeKeySpec);

            PBEParameterSpec pbeParameterSpec = new PBEParameterSpec(salt, 99999);
            Cipher cipher = Cipher.getInstance("PBEWithSHA1AndDESede");
            cipher.init(Cipher.DECRYPT_MODE, secretKey, pbeParameterSpec);

            try (CipherInputStream cis = new CipherInputStream(fis, cipher);) {
                IOUtils.copy(cis, outputFile);
            }
        }
    }
}

After executing the main, the plainfile.txt and the plainfile.txt2 are equal. The plainfile.des is crypted.

IOUtils.copy is a method in apache.commons-io, which internally reserves a buffer and writes all bytes from one stream to another. It's just the byte[] input = ... extracted into a method, plus using try-with-resources. This keeps the code simple and better readable.