Posts: 9
Joined: Sun Dec 16, 2018 9:06 am

ssh size

Sun Dec 16, 2018 12:32 pm

Hi everyone I have a question you can change in ssh key big instead of the standard size

tpyo kingg
Posts: 809
Joined: Mon Apr 09, 2018 5:26 pm
Location: N. Finland

Re: ssh size

Sun Dec 16, 2018 1:13 pm

You can make 4096-bit RSA keys if that is what you are asking. Take a look at the manual page for ssh-keygen. See the options -b and -t for available bits and key types.

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man ssh-keygen
That will give you far more information than you are looking for, but buried in that reference document is material about your choice of keys and their possible sizes.

DSA: don't use anymore - ever - it is easy to break
RSA: use at least the default of 2048 bits but avoid if possible
Ed25519: fixed key length
ECDSA: 256, 384 or 521 bits

Currently it looks like Ed25519 and ECDSA may have the best algorithms so if you can use those if possible, prefereably Ed25519.

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ssh-keygen -t ed25519 -f ~/.ssh/my_key_name_ed25519 -C 'me from the desktop'
However, RSA might be needed instead for backwards compatibility with some older hardware tokens.

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