Cryptography Meta-blog The Furry Fandom

Lightning Round

An assortment of topics that don’t quite deserve their own dedicated blog post.

Last year I wrote a grab-bag post titled, Don’t Forget To Brush Your Fur, because I’m terrible at SEO or making content easily discoverable.

In the same vein as that previous example, this is going to be in the style of Lightning Round talks at technology conferences.

Why are we doing this again?

I maintain a running list of things to write about, and cross ideas off whenever I cover a topic.

After a few months of doing this, I realize most of what remains is kinda interesting but not quite interesting enough to warrant a dedicated entry.

It always needs more isogenies.
(Art by Lynx vs Jackalope)


Asymmetric Key Wear-Out

Last year, I wrote about cryptographic wear-out for symmetric encryption. That post has attracted quite a bit of feedback from folks requesting comparisons against other block cipher modes, etc. One topic that I didn’t see requested much, but is equally interesting, is how this reasoning can be applied to asymmetric cryptography (if at all).

Let’s get one thing clear: Cryptography keys don’t “wear out” in the same sense as a physical key might. What we’re talking about is an ever-increasing risk of a collision occurring in random nonces.

ECDSA Key Wear-Out

ECDSA signatures involve a one-time secret, k. The scalar multiplication of k and the base point for the curve is encoded as half of the signature (r), while its modular inverse is multiplied by the sum of the truncated message hash and the product of r and the secret key to produce the other half of the signature (s).

If your selection of k is biased, or k is ever reused for two different messages, you can leak the secret key.

Strictly speaking, for any given ECDSA curve, there is only one k value that corresponds to a given r for all users (n.b it’s not distinct per keypair).

This means that all users of e.g. ECDSA over NIST P-256 have to worry about a shared cryptographic wear-out: After 2^112 signatures, there is a 2^-32 chance of a single collision occurring.

Fortunately, the search space of possible k-values is enormous, and this will not impose a real-world operational risk in the near future. If you’re worried about multi-user attacks, P-384 gives you a wear-out threshold of 2^176 messages, which we’re probably never going to achieve.

RSA Key Wear-Out

In order to calculate the wear-out for an RSA message, you first have to begin with an attack model. Previously, we were looking at algorithms that would become brittle if a nonce was reused.

RSA doesn’t have nonces. You can’t attack RSA this way.

But let’s assume that such an attack did exist. What might the safety limit look like? There are two remaining possible considerations for RSA’s security against cryptographic wear-out: Key size and padding mode.

RSA private keys are two prime numbers (p, q). RSA public keys are the product of the two primes (n) and a public exponent (e) that must be coprime to (p-1)(q-1). (In practice, e is usually set to 3, 65537, or some other small prime.)

The security of RSA is subexponential to key size, based on the difficulty of integer factoring attacks and the requirement for p and q to be prime numbers.

This primeness restriction doesn’t apply to your message. The padding mode dictates your upper limit on message size; e.g., PKCS#1 v1.5 padding will take up at least 3 bytes:

  • For encryption, x = 0x00 || 0x02 || r || 0x00 || m, where r is random padding bytes (minimum 8 bytes).
  • For signatures, x = 0x00 || 0x01 || 0xFF..FF || 0x00 || m.
  • In either case, the padding is always at least 11 bytes long.

So if you have 2048-bit RSA keys, you can encrypt or sign up to 245 bytes (1960 bits) with PKCS#1 v1.5 padding. This corresponds to a safety limit of 2^974 messages.

HMAC Wear-Out?

To keep things simple, the security of HMAC can be reduced to the collision risk of the underlying hash function.

If you’re trying to estimate when to rotate symmetric keys used for HMAC, take the birthday bound of the underlying hash function as your starting point.

  • For SHA-256, you have a 50% chance of a collision after 2^128 messages. For a 2^-32 chance, you can get 2^112 messages out of a single key.
  • For SHA-384, this is 2^176 messages.
  • For SHA-512, this is 2^240 messages.

In either case, however, these numbers might as well be infinity.

With apologies to Filippo Valsorda.

Asymmetric Commitments

Did you know that fast MACs such as GHASH and Poly1305 aren’t random-key robust? This property can matter in surprising ways.

Did you know that ECDSA and RSA don’t qualify for this property either? This is related to the topics of malleability and exclusive ownership. You can learn more about this in the CryptoGotchas page.

Essentially, if a signature scheme is malleable or fails to provide exclusive ownership, it’s possible to construct two arbitrary (m, pk) pairs that produce the same signature.

Any nonmalleable signature scheme with exclusive ownership (i.e. Ed25519 with low-order point rejection and canonical signature checks, as provided by the latest version of libsodium) provides sufficient commitment–mostly due to how it uses a collision-resistant cryptographic hash function. (It’s also worth noting: HashEdDSA doesn’t. Isn’t cryptography fun?)

Generally, if you need random-key robustness, you want to explicitly make it part of your design.

Against “Fluffies”

In my blog post about the neverending wheel of Furry Twitter discourse, I mentioned the controversy around SFW spaces for underage furries.

Everything I said in that post is still accurate (go read it if you haven’t), but I want to emphasize something that maybe some people overlooked.


Underage furries calling themselves “fluffies” is a bad idea, for two reasons.

Divide and Conquer

The first reason is tactical, and not specific to what they’re calling themselves: If you label yourselves separately from the larger furry community, you make it much easier to be targeted–especially by propaganda. There’s a severely disturbed alt-right fringe to the furry fandom (dubbed alt-furry, the Furry Raiders, and so many other names) that would love nothing more than to sink their claws into younger furs.

It’ll start innocently enough (“Yay, you have your own space!”), but it will quickly accelerate (“Congrats on kicking those degenerates to the curb!”) to horrible places (“All LGBTQIA+ people are degenerates”), gliding on the wings of edgy humor.

This descent into madness is also known as the PewDiePipeline and all parents of furries should be made aware of it, lest it happen to their child:

It bears emphasizing: This existence of a PewDiePipeline within the “fluffy” space is not predicated on the intentions of the proponents. They can have all the best intentions in the world and it will still happen to their microcosm.


Preventing this from happening will require an almost inhuman degree of vigilance and dedication to correcting discourse from going sour. None of us are omniscient, so I wouldn’t take that bet.

Pre-Existing Terminology

The second reason the “fluffies” label is a bad idea is more specific to the word “fluffies” in particular: It already refers to a very disturbing meme on 4chan from not-very-many years ago: Fluffy Abuse Threads.

I’m intentionally not including any videos or images of this topic. There just aren’t enough content warnings for how gross this content is.

By calling yourselves “fluffies”, the most deranged 4chan-dwellers and/or Kiwi Farms lurkers on the Internet will begin associate you with the “fluffy abuse” memes, and may even act accordingly. In their twisted minds, they may even rationalize their conduct as if somehow you’re consenting to the abuse, by virtue of what you call yourselves.

Look, I get it: When you’re young, the over-sexualization of the media can be very uncomfortable, and it’s natural to want to avoid it. Additionally, it’s only human to want your own special club with a special name to hang out with your exclusive (n.b. same-age) community.

But please think carefully about what you’re doing, how you’re doing it, and which adults you decide to trust.

Also: maybe talk to older queers and/or furries about the history of the Furry Fandom, Pride, and kink before you make dangerous moves that make you more vulnerable to the worst humanity has to offer? Even if you don’t agree with us, we don’t want to see you get hurt.

There definitely is room in the furry fandom for people who are not comfortable with sexual content, or simply don’t want to be inundated with it all the damn time. It doesn’t need to be an exclusive thing or concept; instead, it should be normalized.

Ultimately, there’s probably a lot of work to be done to ensure kids and families have a safe and enjoyable furry con experience during daylight hours without repressing the queer and sexual identities of consenting adults at night. The best way to get from here to there is to talk, not to isolate.

Otherwise, we’ll keep seeing occurrences like this:


The onus here is going to be largely on furry convention staff and chatroom moderators to actually listen to people reporting abusive behavior. They haven’t always been good about that, and it’s time for change.


A Meditation on Furries and Cringe

Every once in a while, I get a comment or email like this one:

The biggest magnet for poorly-reasoned hate comments is, surprisingly, my tear-down of the “sigma male” meme.

You’d think the exposure of TheDonald’s non-CloudFlare IP address would draw more ire than having correct opinions on masculinity, but here we are.

Art by Sophie

Let’s talk about masculinity for a moment, guys.

There is nothing manlier than being your authentic self. Even if that means liking some “girly” things. Even if that means being soft and vulnerable at times. Even if that means actually conforming to some stereotypes perpetuated by toxic masculinity when it coincides with your likes and interests. You do you.

But this isn’t just true of the male gender. Authenticity is the epitome of humanity. There’s nothing that stops women and enbies from being ruthlessly themselves.

You can’t be authentic when you’re participating in Cringe Culture, which blindly tears large swaths of people down to stoke the feelings of superiority in the people who evade its blast.

People are weird. I’m weird. I don’t expect everyone to like me, nor do I want them to. (Parasocial relationships suck!)

It’s okay to be a little obsessed about something other people look down on just because you happen to like it. Just make sure you’re not eschewing your adult responsibilities. (We all have bills to pay and promises to keep to the people that matter to us.)

If people don’t like you because you suddenly revealed your fondness for classic video games, rock-tumbling, or linear algebra? Fuck ’em. May the bridges you burn light the way to people who will appreciate you for who you truly are.

I’ve been told my blog is “weapons grade cringe” before, because I dared talk about encryption while having what, to most adults, comes across as little more than a cartoon brand or company mascot.

Furries and Blue State Privilege

I sympathize with most queer people and/or furries for not wanting to subject themselves to the bigotry that runs rampant in Red States, but the ones who are jerks to other members of their community for living in those states, I can do without.


Being an asshole to someone because they live in, or are moving to, a state whose politics you dislike is equal parts stupid, selfish, and self-defeating:

  • It’s stupid because there’s no reason for expressing prejudice or painting with broad brushes. For example: “Florida Furs are bad people” is an attack on the author of this blog.
  • It’s selfish because not everyone who wants to leave these states has the resources or opportunity to do so, so all you’re doing is shining a spotlight on your own privilege. Way to show your entire ass to the community.
  • It’s self-defeating because of the way the U.S. political system is architected:

    If you wished for a genie to move every LGBTQIA+ person to the west coast of the United States, within a few years you’d essentially reduce support for LGBTQIA+ rights to approximately 6 out of 100 votes in the US Senate and 68 out of 435 in the House of Representatives.

    When you factor in who owns the land in the big tech cities (San Francisco, Seattle, etc.) and how much political and economic power they wield, it becomes very clear that your shaming of others for not boarding the bandwagon serves the interests of the worst of humanity: Landlords and venture capitalists.

    Not a good move for people who claim to be progressive, and want to achieve progressive political outcomes nationwide.

The fact that some states have horrendous laws on the books, even worse bastards enforcing these laws, and somehow even more terrible politicians gatekeeping any meaningful progress from changing the system isn’t ever going to be improved from the outside.

I say all this, and I acknowledge Florida does suck in a lot of obvious ways: Our governor (Ron DeSantis) has a disposition that would actually be improved if he wore clown make-up to press appearances. We also have far too many furries that are anti-maskers, anti-vaxxers, or both.

But when furries go out of their way to shame someone, simply for living here? You’re not helping. Seriously stop and think about your priorities.

And maybe–just maybe–be surgically precise when you decide insults are warranted.

Now that I’ve flushed the blog post topic buffer, I’m fresh out of ideas. Let me know some topics that interest you in my Telegram group so I don’t get bored and eventually write Buzzfeed-quality crap like this:

In hindsight, ideas like this are 90% of the reason Cringe Culture refuses to die.

By Soatok

Security engineer with a fursona. Ask me about dholes or Diffie-Hellman!

5 replies on “Lightning Round”

On “fluffy cons”:
I agree with you on all points. One thing I think a lot of folks on the other side of the “debate” misses, though: don’t fully SFW furcons already exist? Isn’t Anthro Northwest one of them? They obviously don’t regulate what folks do in the privacy of their hotel rooms, but the code of conduct explicitly states that the convention space must be kept PG/SFW.
They did this *perfectly*, imo. Kids can feel comfortable in these spaces, without needing to exclude anyone else. Which is just another point of evidence reinforcing that there’s no need for a separate distinction for “fluffies”.

There was a bit of controversy with ANW’s chairman being a religious conservative with allegedly homophobic views. The closest I can find years later about this topic is this, though:

Consequently, I’m cautious with saying Anthro Northwest did it “perfectly”. They seemed to have struck a good balance in past cons, and that’s commendable. If the whispers about the chairman are true, ANW might clamp down harder in the future. I’m loathe to endorse right-wing suppression of queer culture by calling it “perfect”.

Totally fair point; I did not know this. I certainly hope they continue to strike that balance into the future — but regardless, perhaps “perfect” was a strong term.

Bark My Way

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