151–160 of 433 posts
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It's not quantum-safe though.
Larger keys won't make the algorithms quantum-safe either.
So it would be a slight increase in complexity, but if we are able to build a machine with enough qbits to crack 1024 keys, I don't think the engineering is all that far off from slightly scaling things up 2x-10x.
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> "Keys of 512 bits have been shown to be practically breakable in 1999 when RSA-155 was factored by using several hundred computers and are now factored in a few weeks using common hardware." So we went to a few weeks to 8h in 14 years give or take
86 hours. 8 dollars. I wonder how scalable it is. They only used: > We chose a server with 8 dedicated vCPUs (AMD EPYC 7003 series) and 32 GB of RAM from Hetzner Not very beefy really. Beating this time is easily in range of, what, millions of people high end gaming machines?
why aren't people just defaulting to 2048?
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Probably because RSA 2048 is not yet broken, and once there we still have RSA 4096 to lean back on which is since quite some time the most common key size for most things using RSA (DKIM being one of the exceptions). In the context of DKIM we're waiting for Ed25519 to reach major adoption, which will solve a lot of annoyances for everyone.
> Probably because RSA 2048 is not yet broken […] 3072 has been recommended by various parties for a few years now: * https://www.keylength.com
Me writing over 14 years ago: https://blog.jgc.org/2010/06/facebooks-dkim-rsa-key-should-b... This was doable 14 years ago for 512-bit keys.
For a number of years it was (non-officially) thought to be a feature to use weak DKIM keys. Some folks argued that short keys allowed you to preserve deniability, since DKIM signatures would only be short-lived and nobody would be able to use DKIM signatures to prove that any email was authentic. (I’m not saying that this is why most companies used short keys, just that there was a general view that short keys were…
Could someone help me understand why we're not dramatically ramping up key sizes across the board on all encryption? Not as a solution, but as a buy-some-time measure. Compute is rapidly increasing, there is continuous chatter about quantum and yet everyone seems to be just staring at their belly buttons. Obviously bigger keys are more expensive in compute, but we've got more too...why only use it on the cracking sid…
I am acutely aware that there are SOME places where software only supports RSA and only supports up to 1024-bit or 2048-bit keys, and that is a legal requirement. Ramping up key sizes would be great but even 2048-bit keys aren't quite secure against certain kinds of actors (even disregarding hammer-to-head style of attacks)
> Even simple things like forcing TLS 1.3 instead of 1.2 from client side breaks things
... kind've a case in point about the pace of required improvements.
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Ok, so there's a time window where it's possible to prove that you were the sender. And if I use a qualified timestamp service to sign all messages arriving in my inbox, then I can prove that you were the sender indefinitely.
Something like that, as long as you can also prove I hadn’t published the key prior to that. If I publish at random times and to random URL, that may be challenging.
So I agree that it brings deniability, but I don't agree that it still meets the original purpose of verifying the sender.
Earlier quoted context omitted.
For a number of years it was (non-officially) thought to be a feature to use weak DKIM keys. Some folks argued that short keys allowed you to preserve deniability, since DKIM signatures would only be short-lived and nobody would be able to use DKIM signatures to prove that any email was authentic. (I’m not saying that this is why most companies used short keys, just that there was a general view that short keys were…
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why aren't people just defaulting to 2048?
Any tips on how to easily fetch the key length of DKIM-Keys from DNS? Just by looking at the DNS entries I can't easily determine the key length ;)