Testing SSH Keygen (rounds of key derivations)

keygentest.sh

#!/usr/bin/env bash

set -eu

## shellcheck ./keygentest.sh

for j in 16 32 64 100 150 256; do
    echo -n "-a $j takes on average ";
    # shellcheck disable=SC2034
    for i in {1..20}; do
        ssh-keygen -qa $j -t ed25519 -f test -N test;
        time ssh-keygen -qa $j -N tost -pP test -f test;
        rm test{.pub,};
    done 2>&1 | grep real | awk -F m '{print $2}' | sed 's/,/./;s/s//' | LC_ALL=C awk '{sum+=$1} END{print sum/NR}';
done

testing_ssh_keygen.md

Testing SSH Keygen (rounds of key derivations) to slow down passphrase verification and increase resistance to brute-force password cracking. The default is 16 rounds.

ed25519 - Apple MacBook Pro 2012 (Legacy Intel(R) Core(TM) i5-3210M)

-a 16 takes on average 0.36155
-a 32 takes on average 0.70905
-a 64 takes on average 1.43805
-a 100 takes on average 2.17795
-a 150 takes on average 3.25105
-a 256 takes on average 5.6617

ed25519 - GCP CE t2d-standard-1 - Ubuntu Pro 20.04 LTS / FIPS Mode (AMD EPYC 7B13)

-a 16 takes on average 0.25415
-a 32 takes on average 0.4915
-a 64 takes on average 0.96715
-a 100 takes on average 1.50855
-a 150 takes on average 2.24455
-a 256 takes on average 3.8302

ed25519 - Apple MacBook Pro 2021 (Apple M1 Pro - 10 Core)

-a 16 takes on average 0.22655
-a 32 takes on average 0.4474
-a 64 takes on average 0.88965
-a 100 takes on average 1.38955
-a 150 takes on average 2.0816
-a 256 takes on average 3.54645

ed25519 - Lenovo ThinkStation P-360 Tiny - Ubuntu 22.04 LTS (12th Gen Intel(R) Core(TM) i7-12700T)

-a 16 takes on average 0.1749
-a 32 takes on average 0.3485
-a 64 takes on average 0.69165
-a 100 takes on average 1.08
-a 150 takes on average 1.62095
-a 256 takes on average 2.7616