3 ms·

RSA is safe. You should keep using it. Modern crypto is starting to use ECDSA because smaller key size means faster computation, but you wouldn't notice the dif

• nickysielicki 10y ago
  (edit: this is wrong, see below.) > Modern crypto is starting to use ECDSA because smaller key size means faster computation, but you wouldn't notice the difference in SSH anyway. If you're using SSH for tiny bits of text (eg: bash) you won't. If you're using SSH to move gigabytes of binary data (eg: rsync) you might.
  • ycmbntrthrwaway 10y ago
    > If you're using SSH to move gigabytes of binary data (eg: rsync) you might. No. RSA or other asymmetric crypto is only used during connection establishment for authentication. Then symmetric key is established using DH and you use symmetric encryption to encrypt the data.
    • nickysielicki 10y ago
      That makes perfect sense. Apologies for spreading incorrect information, and thanks for correcting me. I remember changing around my ssh config a while back and seeing lower speeds when rsync'ing from an older laptop. But that makes sense, I recall cranking up my DH group to 16, 4096-bit, and that was probably why it was struggling.
  • throwawayish 10y ago
    No, not at all. What you do notice is using ciphers that are apt for the machine. If both ends are modern x86, for example, then you'd want to use aes256-gcm@openssh.com or aes128-gcm@openssh.com for best performance. Otherwise stick to chacha20-poly1305@openssh.com, which is the default of recent versions.
• Rafert 10y ago
  The link prefers Ed25519 over RSA and uses ECDSA last where possible. It's faster and some also trust djb's work on curves over that from NIST.