Hi all,
I recall a discussion that may have said RSA was not being accepted in f38 and a different type was being preferred, possibly ecdsa?
Can anybody point me to that? (date or subject would help me search)
I generated an ECDSA pair. The public key seems awfully short.
Thanks
Mike Wright wrote:
Hi all,
I recall a discussion that may have said RSA was not being accepted in f38 and a different type was being preferred, possibly ecdsa?
It's only old RSA1 keys which use SHA1 which are not accepted by default. RSA keys which use a SHA2 algorithm are perfectly acceptable.
Though you may use ECDSA or ED25519 keys instead.
Can anybody point me to that? (date or subject would help me search)
I think this is the relevant change:
https://fedoraproject.org/wiki/Changes/StrongCryptoSettings3Forewarning1
I generated an ECDSA pair. The public key seems awfully short.
They don't need to be as large as an RSA key to have similar strength. Though there are reasonable concerns regarding ECDSA. Refer to the "Concerns" section of the Wikipedia page for a starting point:
https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm#Sec...
Or, if you're really into diving in the weeds:
;)
One possible downside to ED25519 is that it's not as widely supported. But unless you depend on some rather old systems, that's not likely a real issue.
On 8/14/23 12:16, Todd Zullinger wrote:
Mike Wright wrote:
Hi all,
I recall a discussion that may have said RSA was not being accepted in f38 and a different type was being preferred, possibly ecdsa?
It's only old RSA1 keys which use SHA1 which are not accepted by default. RSA keys which use a SHA2 algorithm are perfectly acceptable.
Though you may use ECDSA or ED25519 keys instead.
Can anybody point me to that? (date or subject would help me search)
I think this is the relevant change:
https://fedoraproject.org/wiki/Changes/StrongCryptoSettings3Forewarning1
I generated an ECDSA pair. The public key seems awfully short.
They don't need to be as large as an RSA key to have similar strength. Though there are reasonable concerns regarding ECDSA. Refer to the "Concerns" section of the Wikipedia page for a starting point:
https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm#Sec...
Or, if you're really into diving in the weeds:
;)
One possible downside to ED25519 is that it's not as widely supported. But unless you depend on some rather old systems, that's not likely a real issue.
Excellent. Thanks for the detailed explanation.
After reading through your references I settled on ED25591.
:m
Le 2023-08-14 21:16, Todd Zullinger a écrit :
Mike Wright wrote:
Hi all,
I recall a discussion that may have said RSA was not being accepted in f38 and a different type was being preferred, possibly ecdsa?
It's only old RSA1 keys which use SHA1 which are not accepted by default. RSA keys which use a SHA2 algorithm are perfectly acceptable.
What could be helpfull would be to tell people how to create a SHA2 signature key....
I have a ssh connexion problem after upgrading a remote machine to f38 and it is hard to find out what to do to solve the problem.
I succeeded (at last!):
ssh-keygen -t rsa-sha2-256 -b 4096
François Patte wrote:
What could be helpfull would be to tell people how to create a SHA2 signature key....
I have a ssh connexion problem after upgrading a remote machine to f38 and it is hard to find out what to do to solve the problem.
I succeeded (at last!):
ssh-keygen -t rsa-sha2-256 -b 4096
There's no need for that. A simply ssh-keygen -t rsa works (with -b if you want more than the default 3072 bits).
You've actually used a (very slightly) weaker signature algorithm than the default. ;)
ssh-keygen(1) says:
-t dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa
Specifies the type of key to create. The possible values are “dsa”, “ecdsa”, “ecdsa-sk”, “ed25519”, “ed25519-sk”, or “rsa”.
This flag may also be used to specify the desired signature type when signing certificates using an RSA CA key. The available RSA signature variants are “ssh-rsa” (SHA1 signatures, not recommended), “rsa-sha2-256”, and “rsa-sha2-512” (the default).
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François Patte -
Mike Wright -
Todd Zullinger