Often, yes. But also consider the SHA-3 competition.
BLAKE2 seems more widely used than what was chosen for SHA-3 (Keccak). What was submitted for the SHA-3 competition was BLAKE1 (it didn't have a number back then but I think this is clearer) so it's not like NIST said that Keccak is better than BLAKE2, they only said it's better than BLAKE1 (per their requirements, which are unlikely to align with your requirements because of the heavy weighing of speed-in-hardware), but still this is an example of a widely used algorithm that is not standardized.
> how often do you see Serpent being mentioned, despite it having a larger security margin than Rijndael
The goal of an encryption algorithm is not only to be secure. Sure, that has to be a given: nobody is going to use a broken algorithm when given a choice. But when you have two secure options, the more efficient one is the one to choose. You could use a 32k RSA key just to be sure, or a 4k RSA key which (to the best of my knowledge) everyone considers safe until quantum. (After quantum, you need something like a 1TB key, as djb humorously proposed.)
Wikipedia article on Serpent: "The 32 rounds mean that Serpent has a higher security margin than Rijndael; however, Rijndael with 10 rounds is faster and easier to implement for small blocks."
I don't know that nobody talks about Serpent solely because it was not chosen as winner. It may just be that Rijndael with 256-bit keys is universally considered secure and is more efficient at doing its job.
Re: Serpent, there are many things to unpack here but, in summary, you don't know a priori how large of a security margin you need (given the primary function of a cipher, you want to pick the conservative option), efficiency concerns become much less relevant with hardware-accelerated implementations and years of Moore's law performance uplifts, low-power devices can take advantage of much lighter algorithms than Rijndael OR Serpent, ease of implementation does not equal ease of correct/secure implementation vis-a-vis side channel attacks, and certainly if Serpent was chosen you wouldn't see Rijndael talked about much.
Speculatively, if SHA2 is broken without breaking Merkle-Damgard hashes in general, Blake2/3 could well become SHA4.
Ah, maybe my experience is biased then. I keep coming across BLAKE2 implementations, but rarely hear so much as people considering to use SHA-3 somewhere. If anyone has actual numbers on this, that would be interesting.
It would be good if SHA-3 is being used because then chip makers have a reason to bake it into their hardware, which is exactly where the biggest gain over SHA-2 is expected. If that happens, and all else being equal (no cracks appear in Keccak), I'd be surprised if BLAKE2 remains as popular!
> you don't know a priori how large of a security margin you need
True, so this can be argued to be an educated guess at first. But then confidence increases over time. It seems to be expected that, more than 20 years later, people aren't considering Serpent anymore. Is it because it wasn't chosen as AES? Certainly partially, but BLAKE2 (I'll admit it does seem like an outlier) likely will still be talked about in the future so standardization is not the only factor.
I didn't see actual benchmarks, but Serpent sounds at least three times slower than Rijndael for, by now, no tangible benefit. What would be interesting is if there were AES competitors that are also fully unbroken and are more efficient than Rijndael, or easier to implement, etc.
You can read the original report on the candidates: https://nvlpubs.nist.gov/nistpubs/jres/106/3/j63nec.pdf
To save you some time, one software evaluation is on page 531. Serpent performs worse in software than Rijndael (AES) just about everywhere (note they use categories rather than precise metrics, but you can dig into that if you want). By contrast, one hardware evaluation is on page 539. Serpent has the highest throughput for the lowest "area" i.e. required. These results repeat on p541.
So it depends on whether you are comparing a software or hardware implementation.
The real reason I would have liked that to be the case is so that one could use WebAuthn and Subtle Web Crypto to sign things and have the blockchain natively verify the signature.
As it is, I am hoping that EVM will roll out a precompiled signature verifier for secp256r, which is on the roadmap — they say!
Work is also being done on SNARK-based cross-curve signature verification
But I fully agree, especially with the growing popularity of account abstraction, the EVM desperately needs a secp256r1 precompile!
There's also BLAKE3 and it is amazing. How is its adoption going?
BUT. On security margins, you could argue the Serpent designers were too conservative: https://eprint.iacr.org/2019/1492 It is also true that cryptanalytic attacks appear to fare slightly better against AES than Serpent. What does this mean? A brute force attack has the same number of operations as the claimed security level, say, 2^128 for 128-bit. An attack is something better than this: fewer operations. All of the attacks we know about achieve slightly less than this security level - which is nonetheless still impossible to do - but that comes at a cost: they need an infeasible amount of memory. In terms of numbers: 9000 TB to reduce 2^128 to 2^126 against full-round AES according to a quick check of wikipedia. For reference, the lightweight crypto competition considered 2^112 to be sufficient margin. 2^126 is still impossible.
In practice, the difference between Serpent and AES in terms of cryptanalytic security is meaningless. It is not an example of NIST picking a weaker algorithm deliberately, or I would argue, even unintentionally. It (AES) was faster when implemented in software for the 32-bit world that seemed to be the PC market at the time.
Regardless, the comparison wasn't intended to argue for a meaningful difference in security margin, but to show that that the winner of the competition, well, wins (in adoption).
Thanks for digging that paper out again. It is really telling that AES only gets a bit of a bump (10-30%) while the other ones gain like 2x or more.
I was about to comment that the competitors to AES were definitely too conservative, and it bit them because of how much slower it made them in software and larger in hardware.
Almost all of these downsides are helpful for password has validation function like bcrypt() because there is nothing to an attacker can to guess much faster than a desktop CPU.
Blowfish was a good cipher at a time when CPUs lacked dedicated trustworthy crypto engines, wide and deep OoO execution capability, and packed-SIMD support. AES and SHA1/2 are commonly implemented in hardware on modern server, desktop and mobile CPUs. Where hardware offloading isn't available ciphers can take advantage of OoO and SIMD to perform vastly more useful work per cycle than stalling on memory accesses.
NIST may or may not consort with your friendly local neighborhood NSA people, who are bright and talented contributors in their own right. That's simply in addition to reading the same mailing lists
At the end, NIST gets to pick a winner and explain their reasonning. What influenced the decision is surely a combination of things, some of which may be internal or private discussions
It is worth noting that while breaking codes is a big part of the NSA's job, they also have a massive organization (NSA Cybersecurity, but I prefer the old name Information Assurance) that works to protect US and allied systems and cryptographic applications.
In the balance, weakening American standards does little to help with foreign collection. Their efforts would be much better spent injecting into the GOST process (Russia and friends) or State Cryptography Administration (China and friends).
While that makes logical sense, the previous actions of the NSA has demonstrated they're not a logical actor in regards to this stuff, or that there's more going on.
Though it can be greatly beneficial for domestic collection. Further, so long as the US remains a dominant player in Tech and Tech-influenced fields like finance, odds are a lot of the world is going to be at least de facto using US standards.
Is that not the case?
> I filed a FOIA request "NSA, NIST, and post-quantum cryptography" in March 2022. NIST stonewalled, in violation of the law. Civil-rights firm Loevy & Loevy filed a lawsuit on my behalf.
> That lawsuit has been gradually revealing secret NIST documents, shedding some light on what was actually going on behind the scenes, including much heavier NSA involvement than indicated by NIST's public narrative.
even if I had never heard of DUAL_EC_whatsit, there's enough here to make me mistrust NIST.
Or the s-boxes in DES, that the NSA suggested to IBM + NIST's predecessor, so as to be resistant to then-not-widely-known differential cryptanalysis? https://web.archive.org/web/20120106042939/http://securespee...
There is a widely held belief that the US IC changed fundamentally in terms of their regard for their own raison d’etre that day.
I'd like to think the US is in the midst of that now, with the Afghan withdrawal and Ukraine war.
I've seen enough blatant disregard for humanity to assume any kind of honesty in the powers that were.
No one can say they pushed some useless or overtly backdoored encryption. That's rarely how Intel agencies work. It's also not how they need to work to maintain their effectiveness indefinitely.
When the CIA is trying to recruit for HUMINT if they can get claws into anything whether it's a business conference that has a 0.1% chance they'll meet some pliable young but likely future industry insider that may or may not turn into a valuable source then they'll show up to every single year to that conference. It's a matter of working every angle you can get.
They aren't short of people, time, or money. And in security tiny holes in a dam turn into torrents of water all the time.
The fact NIST is having non public backroom meetings with NSA, concealing NSA employee paper authors, generating a long series of coincidental situations preferencing one system, and stonewalling FIOAs from reputable individuals. IDK, if was a counter intelligence officer in charge of detecting foreign IC work I'd be super suspicious of anything sold as safe and open from that org.
Well, everything apart from the secret stuff:
"I filed a FOIA request "NSA, NIST, and post-quantum cryptography" in March 2022. NIST stonewalled, in violation of the law. Civil-rights firm Loevy & Loevy filed a lawsuit on my behalf.
That lawsuit has been gradually revealing secret NIST documents, shedding some light on what was actually going on behind the scenes, including much heavier NSA involvement than indicated by NIST's public narrative"
Every single document will be reviewed by a court before being opened up, and any which say "We did this so we can hoodwink the public and snoop on russia and china" won't be included.
Ever since Snowdon we know it's actually "hoodwink the public and snoop on the public"
Russia and China are just an excuse.
I don't know of any cryptographer or cryptography engineer that takes the SHA3 innuendo seriously. Do you?
Additional backstory that might be helpful here: about 10 years ago, Bernstein invested a pretty significant amount of time on a research project designed to illustrate that "nothing up my sleeves" numbers, like constants formed from digits of pi, e, etc, could be used to backdoor standards. When we're talking about people's ability to cast doubt on standards, we should keep in mind that the paragon of that idea believes it to be true of pi.
I'm fine with that, for what it's worth. Cryptography standards are a force for evil. You can just reject the whole enterprise of standardizing cryptography of any sort, and instead work directly from reference designs from cryptographers. That's more or less how Chapoly came to be, though it's standardized now.
My understanding of the Dual-EC problem may be different than yours. As I understand it, the construction is such that if you choose the two constants randomly, it's fine, but if you derived them from a known secret, the output was predictable for anyone who knows the secret. The NIST did not provide proof that the constants used were chosen randomly.
Random choice would be equivalent to encrypting with a public key corresponding to an unknown private key, while the current situation has some doubt about whether the private key is known or not.
First, because its output has unacceptable biases [1,2].
Second, because its presence allows an attacker to create a difficult-to-detect backdoor simply by replacing the key, as apparently happened with Juniper NetScreen devices [3,4].
--- [1] Kristian Gjøsteen, Comments on Dual-EC-DRBG/NIST SP 800-90, draft December 2005. Online: https://web.archive.org/web/20110525081912/https://www.math....
[2] Berry Schoenmakers and Andrey Sidorenko, Cryptanalysis of the Dual Elliptic Curve Pseudorandom Generator, May 2006. Online: https://eprint.iacr.org/2006/190.pdf
[3] Stephen Checkoway, Jacob Maskiewicz, Christina Garman, Joshua Fried, Shaanan Cohney, Matthew Green, Nadia Heninger, Ralf-Philipp Weinmann, Eric Rescorla, and Hovav Shacham, A Systematic Analysis of the Juniper Dual EC Incident, October 2016. Online: https://www.cs.utexas.edu/~hovav/dist/juniper.pdf
[4] Ben Buchanan, The Hacker and the State, chapter 3, Building a Backdoor. Harvard University Press, February 2020.
What's a "verifiably random" key?
It's both.
It is bad enough even without the constants
https://blog.cryptographyengineering.com/2013/09/18/the-many...