OpenSSH 9.0 Released With Hardening Against Future Quantum Computers
OpenSSH 9.0 is a big release and with it comes with a few notable changes.
First up, OpenSSH 9.0 switches scp from using the legacy SCP/RCP protocol to now using the SFTP protocol internally by default. This is a change OpenSSH had been working towards with the groundwork laid in prior releases for the scp utility to use SFTP internally.
Another notable change is OpenSSH 9.0 SSH/SSHD uses the hybrid Streamlined NTRU Prime + x25519 key exchange method by default in order to resist attacks by quantum computers in the future. OpenSSH developers are making this change now to improve security to fend off "capture now, decrypt later" attacks once quantum computers are available that have the ability to decrypt captured SSH ciphertext.
OpenSSH is improving security now ahead of more advanced quantum computers in the future.
Also a rather useful change with OpenSSH 9.0 is that the sftp-server implementation adds support for the copy-data extension to support server-side copying of files/data. The sftp utility also adds a "cp" command to allow the SFTP client to perver server-side file copies.
OpenSSH 9.0 is rounded out by a number of portability improvements, various bug fixes, and other improvements.
Downloads and more details on OpenSSH 9.0 via OpenSSH.com.