Jsch

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

Why JSch?

Originally, our motivation to develop this stuff is to
allow users of our pure java X servers,
WiredX,
to enjoy secure X sessions. So, our efforts had
mostly targeted to implement the SSH2 protocol for X11 forwarding.
Of course, however, we are now also interested in adding other
functionality like port forward, file transfer, terminal emulation, etc.

SSH2

Needless to say, SSH provides support for secure remote login,
secure file transfer, and secure TCP/IP and X11 forwarding.
It can automatically encrypt, authenticate, and compress
transmitted data. The SSH protocol is available in two
incompatible varieties: SSH1 and SSH2. SSH2 was invented to
avoid the patent issues regarding RSA (RSA patent has expired),
and to fix some data integrity problem that SSH1 has,
and for a number of other
technical reasons. SSH2 protocol has been standardized on
IETF Secure Shell working group and drafts related to SSH2 protocol are available on the web. In developing JSch, we are now referring to following documents:

• SSH Protocol Architecture
• SSH Transport Layer Protocol
• Diffie-Hellman Group Exchange for the SSH Transport Layer Protocol
• SSH Connection Protocol
• SSH Authentication Protocol

Features

The current JSch has the following features.

• JSch is in pure Java, but it depends on JavaTM Cryptography Extension (JCE). JSch is know to work with:
  • J2SE 1.4.0 or later (no additional libraries required).
  • J2SE 1.3 and Sun's JCE reference implementation that can be
    obtained at http://java.sun.com/products/jce/.
  • J2SE 1.2.2 and later and Bouncycastle's JCE implementation that
    can be obtained at
    http://www.bouncycastle.org/.
• SSH2 protocol support.
• Key exchange: diffie-hellman-group-exchange-sha1, diffie-hellman-group1-sha1
• Cipher: blowfish-cbc,3des-cbc,aes128-cbc,aes192-cbc,aes256-cbc,aes128-ctr,aes192-ctr,aes256-ctr,3des-ctr,arcfour,arcfour128,arcfour256
• MAC: hmac-md5, hmac-sha1, hmac-md5-96, hmac-sha1-96
• Host key type: ssh-dss,ssh-rsa
• Userauth: password
• Userauth: publickey(DSA,RSA)
• Userauth: keyboard-interactive
• Userauth: gssapi-with-mic
• X11 forwarding
• xauth spoofing
• connection through HTTP proxy.
• connection through SOCKS5 proxy.
• port forwarding.
• stream forwarding.
• signal sending.
  The unofficial patch for sshd of openssh will be found in this thread.
• envrironment variable passing.
• remote exec.
• generating DSA and RSA key pairs.
• changing the passphrase for a private key.
• partial authentication
• SSH File Transfer Protocol(version 0, 1, 2, 3)
• packet compression: zlib, zlib@openssh.com
  JZlib has been used.
• hashed known_hosts file.
• NONE Cipher switching.
  High Performace Enabled SSH/SCP supports NONE Cipher switching. Refer to ScpToNoneCipher.java.
• JSch is licensed under BSD style license.

From：http://www.jcraft.com/jsch

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