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A Post-Quantum Future for Let's Encrypt

letsencrypt.org

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Re: A Post-Quantum Future for Let's Encrypt

#151

Post by raphinou »

JoachimS wrote: post #141
tardedmeme wrote: post #88

Earlier quoted context omitted.

Signatures aren't as urgent to replace as encryption keys are. You can wait until someone is about to build a quantum computer, then change all your signatures. Encrypted data is more critical because the NSA's going to store all internet traffic for centuries if it thinks it can decrypt it later.

No, very much no. If store now decrypt later is the problem, then we basically have no problem (Just like what Peter Gutmann argues [2]). The vast, basically all communication over for example TLS need confidentiality in minutes, hours. Not 30-100 years. My bank statement right now, the plans we discuss for the project next year etc. But what is very important crucial, what makes our digital world including secure co…

The open source project I'm working on aims to authenticate artifact downloads (project name is asfaload, in short it is a sigstore alternative). My understanding is that in a post-quantum world, the private key can be derived from an ed25519 pub key. That means that an attacker can generate new signatures. But I don't think an attacker would be able to generate a malicious artifact that matches an existing signature. It would seem that once we are nearing PQC, Asfaload would need to support PQC signatures, and its uses would need to migrate to new keys, but that existing signatures would still be safe to use for validation. Is that right?

Re: A Post-Quantum Future for Let's Encrypt

#152

Post by tardedmeme »

JoachimS wrote: post #141
tardedmeme wrote: post #88

Earlier quoted context omitted.

Signatures aren't as urgent to replace as encryption keys are. You can wait until someone is about to build a quantum computer, then change all your signatures. Encrypted data is more critical because the NSA's going to store all internet traffic for centuries if it thinks it can decrypt it later.

No, very much no. If store now decrypt later is the problem, then we basically have no problem (Just like what Peter Gutmann argues [2]). The vast, basically all communication over for example TLS need confidentiality in minutes, hours. Not 30-100 years. My bank statement right now, the plans we discuss for the project next year etc. But what is very important crucial, what makes our digital world including secure co…

I'll believe that you believe that your bank statements only need to be private for a year, when you upload all of yours until a year ago.

Re: A Post-Quantum Future for Let's Encrypt

#153

Post by GoblinSlayer »

tialaramex wrote: post #102
zem wrote: post #70

Earlier quoted context omitted.

it's worth noting that the zones of thought universe literally had different physics; things like superintelligence and ftl travel were physically impossible closer to the galactic centre but commonplace further out. so the notion of "not physically practical" doesn't apply here.

The "Zones of Thought" is a fun premise for a story but I'm not sure it actually holds up. It is at least an excuse (unlike in say Iain M Banks which just has Star-Trek style "la la la I can't hear you" FTL travel that's basically magic) but I think the abandoned Eschaton series by Stross had a better excuse and even then Stross accidentally blew it up. Maybe since our universe doesn't have FTL any author trying to m…

Do you assume Lorentz relativity is necessary? In Newtonian world there should be no problem with FTL.

Re: A Post-Quantum Future for Let's Encrypt

#154

Post by [deleted] »

mswphd wrote: post #51
tialaramex wrote: post #48

Earlier quoted context omitted.

But that's a miss, it's like one of those Neal Stephenson moments where the creator is using the right language (so it's not like reading William Gibson who clearly has no idea and knows it - he's going for the emotional feel not the technology) but they don't understand what's actually going on. OTP is in theory the correct choice if you don't have working symmetric cryptography but in fact the "Quantum computer" ap…

It's worth noting that the above assumes that grover's is optimal for symmetric crypto. There are not that many quantum attacks against symmetric crypto that are better than grover's, so in some sense this is justified. But there are some attacks for particular constructions https://arxiv.org/pdf/2110.02836 So there is a risk that there are even more improved attacks that people aren't looking for due to the conventi…

[deleted]

Re: A Post-Quantum Future for Let's Encrypt

#155

Post by upofadown »

alansaber wrote: post #148

So what's the timeline for a quantum future? 20 years? 50 years? 100? My concern is that it's primarily a materials science problem (hence, it is going to take a very long time).

If you specifically mean something that can embody Shor's algorithm, it is fairly clear these days that a fundamental breakthrough is required. So the timeline extends from tomorrow to never.

Re: A Post-Quantum Future for Let's Encrypt

#156

Post by tialaramex »

GoblinSlayer wrote: post #153
tialaramex wrote: post #102

Earlier quoted context omitted.

The "Zones of Thought" is a fun premise for a story but I'm not sure it actually holds up. It is at least an excuse (unlike in say Iain M Banks which just has Star-Trek style "la la la I can't hear you" FTL travel that's basically magic) but I think the abandoned Eschaton series by Stross had a better excuse and even then Stross accidentally blew it up. Maybe since our universe doesn't have FTL any author trying to m…

Do you assume Lorentz relativity is necessary? In Newtonian world there should be no problem with FTL.

I am confident that I do not live in a Newtonian world. Not as confident as the characters in Egan's "Incandescence" who live somewhere that those primary school spring balance experiments prove Einstein's physics not Newton's - but very sure considering.

Re: A Post-Quantum Future for Let's Encrypt

#157

Post by JoachimS »

tardedmeme wrote: post #152
JoachimS wrote: post #141

Earlier quoted context omitted.

No, very much no. If store now decrypt later is the problem, then we basically have no problem (Just like what Peter Gutmann argues [2]). The vast, basically all communication over for example TLS need confidentiality in minutes, hours. Not 30-100 years. My bank statement right now, the plans we discuss for the project next year etc. But what is very important crucial, what makes our digital world including secure co…

I'll believe that you believe that your bank statements only need to be private for a year, when you upload all of yours until a year ago.

Sigh, that argument again. I may have used the wrong example, sorry.

How about the current temperature in my bedroom? The battery status of my robomower, Or the vat/tax and total sum I paid at a cash register for the Plopp candy bar earlier today? I could share all this with you if you want.

Depending on where you live, all these systems may, quite possibly talk over TLS and other protocols that include encryption. In some cases unfortunately encryption is the only security mechanism used, when instead device identity, authentication and message authentication is needed. And all are examples where the secrecy requirement is zero or zero after a very short time.

Better examples?

Re: A Post-Quantum Future for Let's Encrypt

#158

Post by JoachimS »

raphinou wrote: post #151
JoachimS wrote: post #141

Earlier quoted context omitted.

No, very much no. If store now decrypt later is the problem, then we basically have no problem (Just like what Peter Gutmann argues [2]). The vast, basically all communication over for example TLS need confidentiality in minutes, hours. Not 30-100 years. My bank statement right now, the plans we discuss for the project next year etc. But what is very important crucial, what makes our digital world including secure co…

The open source project I'm working on aims to authenticate artifact downloads (project name is asfaload, in short it is a sigstore alternative). My understanding is that in a post-quantum world, the private key can be derived from an ed25519 pub key. That means that an attacker can generate new signatures. But I don't think an attacker would be able to generate a malicious artifact that matches an existing signature…

That is how I understand it yes. I can create a new FW and sign it with the vendors key I cracked and it will be trusted to come from the vendor. But generating a malicious FW that has the same signature is still a hash collision problem.

Re: A Post-Quantum Future for Let's Encrypt

#159

Post by redcheeks »

tialaramex wrote: post #48
skmurphy wrote: post #34

We are truly living in a science fiction future where quantum code cracking is not a remote possibility but a near term risk we are planning for. In Vernor Vinge's novel "A Fire Upon the Deep" one of the most valuable commodities were one time pads that are physically transported to communication nodes to enable unbreakable communication. The pads are split into three pieces that are XORed to create the actual pad to…

But that's a miss, it's like one of those Neal Stephenson moments where the creator is using the right language (so it's not like reading William Gibson who clearly has no idea and knows it - he's going for the emotional feel not the technology) but they don't understand what's actually going on. OTP is in theory the correct choice if you don't have working symmetric cryptography but in fact the "Quantum computer" ap…

I have come to the conclusion that it doesn't matter. What matters is that people believe quantum computers will break encryption. And pulling that lever on their seeded fears, via subterfuge, backdoors, surveillance, and maybe a _little math, is too valuable for it not to be pulled.

Re: A Post-Quantum Future for Let's Encrypt

#160

Post by e40 »

tialaramex wrote: post #144
bawolff wrote: post #121

Earlier quoted context omitted.

> But that's a miss, it's like one of those Neal Stephenson moments where the creator is using the right language (so it's not like reading William Gibson who clearly has no idea and knows it - he's going for the emotional feel not the technology) but they don't understand what's actually going on. That feels a bit harsh when reading a book written in 1992. Shor's algorithm was only invented in 1994. There was no ind…

The communication is clearly inflected by Usenet conventions, but I think that's as forgiveable as the choice to have Banks' Culture starships named using our cultural references like "Just read the Instructions" or "Don't Try This At Home". I don't think we're told it actually is Usenet -- it's just that necessarily light speed comms is very slow compared to the pace of life at this scale so it will feel much like U…

The Usenet comms gave me a lot of laughs. It was so cleverly done. It’s been a very long time since I read it, but that is one of the memories I have.
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