Fix "input length must be multiple of 8 for padded decypher" using JAVA JCA

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Java

encryption

cryptography

I'm currently doing an assignment for a college course using Java's JCA. The application takes in a file and encrypts it (or decrypts it) using DES-ECB. I am fully aware that it's not a secure encryption algorithm.

It encrypts fine, I believe, however when decrypting it blows up with a "Input length must be multiple of 8" even though the original message is being padded with PKCS5.

For the encryption I'm using:

Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
    
    cipher.init(Cipher.ENCRYPT_MODE, symmetricKey);

    
    File file = new File(filePath);
    
    FileOutputStream outputStream = new FileOutputStream("encrypted_"+file.getName());

    
    CipherInputStream cipherStream = new CipherInputStream( new FileInputStream(file), cipher);


    byte[] buffer = new byte[MAX_BUFFER]; //buffer para leitura
    int bytes; //bytes a ler

    //Encoder base64 - Apache Commons Codec
    Base64 encoder = new Base64();

    
    while ( (bytes = cipherStream.read(buffer)) != -1 ) {
        
        byte[] encodedBuffer = encoder.encode(buffer);
        
        outputStream.write(encodedBuffer, 0, bytes);
    }

    
    cipherStream.close();
    outputStream.flush();

    return outputStream;

For decryption:

Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
    
    cipher.init(Cipher.DECRYPT_MODE, symmetricKey);

    
    File file = new File(filePath);
    FileInputStream cipheredStream = new FileInputStream(file);

    
    FileOutputStream outputStream = new FileOutputStream("decrypted_"+file.getName());

    
    CipherOutputStream cipherOutStream = new CipherOutputStream(outputStream, cipher);

    byte[] buffer = new byte[MAX_BUFFER];
    int bytes;

    //Decoder base 64 - Apache Commons Codec
    Base64 decoder = new Base64();

    cipheredStream.read(buffer);
    byte[] decodedBuffer = decoder.decode(buffer);
    byte[] output = cipher.doFinal(decodedBuffer);
    cipherOutStream.write(output);

    //TODO bug here -> use this for big files
    /*while ( (bytes = cipheredStream.read(buffer)) != -1 ) {
        byte[] decodedBuffer = decoder.decode(buffer);
        cipherOutStream.write(decodedBuffer, 0, bytes);
    }*/

    cipherOutStream.close();
    cipheredStream.close();

    return outputStream;

I'm just lost and would appreciate knowing what I'm doing wrong.

What I have tried:

I've tried using AES to no avail; I've tried no padding, obviously it didn't work.
I've tried using various variations of DES - nothing.
Also tried to change encrypting key algorithm...