Thirty-two bits is some seriously weak sauce, Barry. 

And wouldn't this only work for a message that's ten letters long? So, like, you could write 'classified,' but you couldn't write, uh, um... 

Glorio Arkona is a legitimate businessman, and like many legitimate businessmen, he has a minor interest in codes and ciphers. They come up reasonably often in his line of work. 

With ten ranks in linguistics and code-breaking bent, he reads most of Korvosa's state and private simple substitution ciphers and homophonic nomenclators like they're written in plain Taldane. Even polyalphabetic substitution ciphers only sometimes stop him short; unbreakable though those may be in theory, practice is a different animal - and Glorio Arkona is very good at what he does. 

(This is why the Korvosan Guard relies on polyalphabetic ciphers as much as possible. (Like, not you in specific, because I don't personally know how many ranks in Linguistics you have as an individual, but this problem in general.) Polyalphabetic ciphers are slow to use, and if someone makes a single mistake it'll garble the entire message from that point going forward, but if you eliminate human error a polyalphabetic cipher is unbreakable without the key, whereas even the most elaborate nomenclators are simply doomed from the start in a world where some people have ranks in Linguistics and ten or twenty hitdice. (Not that we can do away with our nomenclators entirely, since a) polyalphabetic ciphers are slower than encumbered implacable stalker flail snails and b) if one comes through garbled there might not be time to request and receive clarification.))

(For what it's worth, I find the Guard's nomenclators harder to read than pretty much anyone else's. I mostly try and steal the codebooks you're always changing (by the way, your codebook churn used to freak. me. out. before I realized you do it on a schedule. I thought you had a way to learn when someone'd cracked or yoinked one), since that's usually the fastest way to break them.)

(That confession pleases my ears. I'll pass it along to Spellmaster Shafir, she'll be so smug to hear it - I don't myself keep Linguistics ranked, so after I figured a priori that Volshyenek's old codes must have been compromised at some point, Rose was the one who.

Came up with our replacement system. Maybe I'll be able to get her resurrected.

One day. 

Instead of someone else. 

If I live.

Unless fishing diamonds out of Liavara turns out to work? Gods, I hope it works.)

But the Caydenite's "personal code" cipher isn't like anything Glorio's seen in all his years of knavery and skullduggery. 

There isn't a key to lose track of! You cipher your plaintext with a riddle, and the Primate deciphers it with the riddle's answer, which only he knows. Incredible. 

However. It doesn't automatically follow from "has the ability to make supernaturally accurate assumptions when it pertains to something the actor playing them 'would know'" that you would invent personal code ciphers (which possibly only work if you have the ability to make supernaturally accurate assumptions(?)) on the fly, for a pun.

So, the self-styled Megapope is very comfortable with the abilities he allegedly picked up this morning. 

Setting aside for the moment everything except the object-level claim, it isn't immediately clear to Toff Ornelos how this works.

What's the significance of the number? Is 3,573,960,433 a perfect cube...? No, not a cube, although it's a little close to one. (Weird coincidence? Weird coincidence.)

...But is 3,573,960,433 a prime. Did the Primate of Varisia just casually drop a prime number greater than 2,147,483,647? Rent a room for him in Axis, Toff is going to need paper and a pencil for this. Else prestidigitation to paint on the shell of a turtle.

...Well, Toff can't easily rule out the possibility, and he's used all the space on his turtle.

(At least, he's used up the space on the top of the shell. But he can just flip his turtle over and, what's more, the bottom is flatter to write on.)

I hate you.

You can't write on the turtle, I already confiscated him.

Oh, right.

This isn't actual security but there are tradeoffs to make there vis a vis how long encryption takes, and I think this should be fine for any practical purpose. 

There are tradeoffs to make vis a vis how long encryption takes, but none that bear mention with regard to the difficulty of decryption, which makes sense since he's decrypting the message using his divination ability... although Glorio wouldn't have expected the guy to know how to do this, unless there's an in-universe interface like the "battlemap" that makes using the divinatory power to crack ciphers an automatic action for the game's Player. 

...Also, you'd expect him to say "cipher it however you want, I can figure it out," if he could crack any code just by looking at it. So the cipher probably doesn't rely on the supernatural to work, it's imitable tech from the lore dump about Earth. Which means decryption is easy if you know the key.

Toff doubts that the decryption is easy if you know the key - call it a wizard's intuition -, but it must at least be possible...

The wizard isn't sure, after mere minutes' thought, as to the precise nature of the Primate's one-way function, but that's of no real consequence unless he finds himself wanting to read the Megapope's mail - Toff can invent his own riddle. 

The first place his mind goes is that it's easier to multiply two prime numbers than to find the prime factors of the number so created and huh that's probably what the Primate did.

I wish I had a gazillion Intelligence points and a stronger math background, it seems so sweet. 

It really, really is. 

If the cleric used a method like the one Toff is bashing out on the back of his turtle on the sleeve of his robes, he must have a secret number roughly as long as the public one, and plans to raise the ciphertext to the power of his secret number before dividing it by the public number... oh! or combine those steps while you square and multiply...

On any other day this would be the most interesting idea he was exposed to. As-is, it barely merits mentioning. 

Oh, but the divisor is much too small. 

Glorio, at least you get 8+Int skill ranks a level. I'm a Fighter. I'd need an Int mod six higher than yours just to be even. There are so many skills I'd love to have more ranks in that Linguistics dropped off the bottom of the list - I can't even recognize a forgery unless the DC is 10 or lower; the skill is "trained only."

That seems like an oversight on nandwich's part rather than deliberate characterization.

Ditto. I'd bet money that nandwich just thought, "eh, she has bonus languages from a high Int score which can represent any linguistic education even if she doesn't explicitly have a rank in the skill," and forgot that you needed it to detect forgeries.

The two of you could be right about this, but it's a bit of a cold comfort, no? "Oh, don't worry that you can't even roll to interpret 'the simplest messages (DC 20)' in Taldane if the Taldane is in an 'incomplete or archaic form,' it's only because your omnipotent Creator made a mistake."

nandwich if you're reading this please zap Rovagug to death.

'Steganogram!' 

Oh, and while I'm looking at it, there's a mistake in my build. Dirty Fighting only counts as Combat Expertise "for the purposes of meeting the prerequisites of the various improved combat maneuver feats, as well as feats that require those improved combat maneuver feats as prerequisites." Whirlwind Attack isn't a combat maneuver feat. 

With a modulus of three and a half billion, I can't imagine it taking longer than a few months to break the encryption... ballparking it, there are five and a half thousand primes to check, assume five minutes each, that's 27500 minutes, divide by sixty for hours, divide by eight for man-days, take a week off sick for carpal tunnel, that's 64 days to break the code. 

Two months. Barry.

Barry.

...Two months isn't terrible...

Two months for one person.