Secure Copy (SCP) with Java

SCP allows the files in the local/remote file system to be copied to the local/remote file system

Chanaka Lakmal
2 min readFeb 15, 2017
Source: http://cdn.journaldev.com/wp-content/uploads/2011/02/jsch-example.jpg

What is SCP?

SCP (Secure Copy) allows the files in the local file system or a remote file system to be copied to the local files system or a remote file system. This uses SSH for data transfer and provides the same authentication and same level of security as SSH.

Authentication

Authentication between two hosts can be done using the ‘private and public key pair’ or ‘username and password’. But user has to make sure that the public key of the local machine should be saved in authorized_keys of the remote machine.

Test SCP

Note: The remote host can be the same localhost. No need to have a actual remote machine with remote IP.

How to SCP with Java?

JSch library which is a pure Java implementation of SSH2. JSch allows the user to connect to an sshd server and use port forwarding, X11 forwarding, file transfer, etc., and the user can integrate its functionality into the user’s own Java programs. JSch is licensed under BSD style license.

Design and Implementation

Initially, the user has to identify the remote hosts that the user is going to copy the files from and copy the files to. It can be a host-name or an IP. Then the user has to create a com.jcraft.jsch.Session using createSession(...) method and parsing the required parameters, in order to work with SCP.

In this example the private key is provided for the authentication. So that, the public key of local machine is saved in authorized_keys of the remote machine.

This is how the user can SCP files from the remote host to localhost. User has to provide the session he has created using createSession(...) method.

This is how the user can SCP files from localhost to a remote host. User has to provide the session he has created using createSession(...) method.

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Chanaka Lakmal

CS PhD Student at UWaterloo | ex-WSO2 (Associate Technical Lead)