December 16, 2025

Speed freaks vs purists: SSH gets spicy

High Performance SSH/SCP

Faster SSH lands: fans cheer, purists demand upstream

TLDR: HPN‑SSH promises big speed boosts for secure connections and file transfers, with parallel cryptography and auto‑resume. The crowd’s split: many want it merged into official OpenSSH, others say “use Mosh + rsync,” and there’s confusion over whether both ends need HPN‑SSH for full benefits.

HPN‑SSH just dropped a go‑fast upgrade for secure remote connections and file copies—claiming up to 59% faster than older OpenSSH thanks to a souped‑up, multi‑threaded cipher. In plain English: SSH (remote login) and SCP (file copy) get a turbo button. The devs even ship Ubuntu/Fedora packages and boast auto‑resume on failed transfers. The crowd? Split. Some are hyped, others clutch pearls.

Leading the drama, josephg and freedomben want the speed without installing a custom fork. Their chorus: “put it in the official OpenSSH or we’re not touching it.” Meanwhile, the mosh evangelists crash the party with “just use Mosh and toss in rsync,” turning the thread into a throwdown: faster bulk transfers vs comfy interactive sessions. One commenter summed the vibe with a meme‑y shrug: “I rsync and chill.”

Confusion flared when ollybee asked if you need HPN‑SSH on both ends to see the gains—cue a wave of explanations and guesses. The official page says it’s built on OpenSSH 9.9 and ships widely, but readers still want a simple “yes or no” answer. Then baden1927 dropped a word salad about ports and tunneling that had everyone re‑reading twice.

Under the hood: parallelized ChaCha20 (the default cipher), smarter buffers for long‑distance, high‑speed links, and a GitHub drop at HPN‑SSH. The NSF grant backstory adds prestige, but the comment mood is clear: Speed is cool—trust and convenience rule.

Key Points

  • HPN-SSH 18.6.2 is released, built against OpenSSH 9.9p2.
  • The ChaCha20-Poly1305 cipher in HPN-SSH is parallelized and uses optimized Poly1305 from OpenSSL, yielding a 59% speed improvement over OpenSSH 9.4.
  • Packages for HPN-SSH are available for Ubuntu (PPA), Fedora (COPR), and Debian (documented installation).
  • PSC developers received NSF funding (Award #2004012) in 2020 for four years to add features and performance optimizations to HPN-SSH.
  • Features delivered include resuming failed transfers and integrating AES-NI into multithreaded AES-CTR (available since HPN-SSH 15v4 for OpenSSH 8.7), and parallelization of ChaCha20.

Hottest takes

"Any chance this work can be upstreamed" — josephg
"I’m wary about using a forked SSH" — freedomben
"It’s not clear if you need it on both ends" — ollybee
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