password protected zip file issue

Question

User upload the file, i need to password protect the file and then zip it put in a storage server which is different from the server where my code is running. So i use AESEncrypter to encrypt the file and jcraft.jsch.ChannelSftp to transfer the file to the server.

public ResponseEntity<ResponseWrapper> uploadFile(@RequestParam("uploads") MultipartFile file) throws Exception {
    FileOutputStream fos = new FileOutputStream("outputfile.zip");
    AESEncrypter aesEncrypter = new AESEncrypterBC();
    aze=new AesZipFileEncrypter(fos, aesEncrypter);
    aze.add(file.getOriginalFilename(), file.getInputStream(), "test123");

    JSch ssh = new JSch();
    Session session = ssh.getSession("username", "Servername", 22);

    config.put("StrictHostKeyChecking", "no");
    session.setConfig(config);
    session.setPassword("*****");
    session.connect();
    Channel channel = session.openChannel("sftp");
    channel.connect();

    sftp = (ChannelSftp) channel;
    sftpChannel.put(file.getInputStream(), "/storedfiles/outputfile.zip");
}

File is getting transferred to the server, but when i download that transferred file and try to open it says "Errors were found opening ".." you cannot extract file.. do you want to fix the problems". Not sure why i am getting this issue, also it creates a file in local server, which line is causing that?

I tried replacing this line

aze=new AesZipFileEncrypter(fos, aesEncrypter);

with

aze=new AesZipFileEncrypter("outputfile.zip", aesEncrypter); 

but dint work.

Answer 1

I placed the file in remote server, read that in output stream and then password protected, solved my issue.

public ResponseEntity<ResponseWrapper> uploadFile(@RequestParam("uploads") MultipartFile file) throws Exception {
JSch ssh = new JSch();
Session session = ssh.getSession("username", "Servername", 22);

config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.setPassword("*****");
session.connect();
Channel channel = session.openChannel("sftp");
channel.connect();

sftp = (ChannelSftp) channel;
OutputStream os = sftp.put("/storedfiles/outputfile.zip");

AESEncrypter aesEncrypter = new AESEncrypterBC();
aze=new AesZipFileEncrypter(os, aesEncrypter);
aze.add(file.getOriginalFilename(), file.getInputStream(), "test123");
if(aze != null) {
 aze.close();
}    
}