Decipher script and RSA factoring

[ayvango]

I'm already get used to fantasy games ignoring physics. But ignoring math is something new to me. And using decipher script to decode RSA with sufficiently high check breaks the math. How should I live with it?

I suppose if I need to forge fantasy version of math. How should it look like?

[Vizzerdrix]

In cryptography and security Edit
RSA (cryptosystem), the Rivest-Shamir-Adleman cryptosystem, a cryptosystem for public-key encryption
RSA Conference, an annual cryptography convention
RSA Factoring Challenge, a computational number theory challenge aimed at factorizing a given set of semi-prime numbers
RSA numbers, a set of numbers that have as factors two prime numbers (semi-prime keys)
RSA Security, a U.S. network security provider, a subsidiary of Dell Technologies


What one are you talking about, and is it something that whould even exist in a fantasy setting?

[OldTrees1]

I'm already get used to fantasy games ignoring physics. But ignoring math is something new to me. And using decipher script to decode RSA with sufficiently high check breaks the math. How should I live with it?

I suppose if I need to forge fantasy version of math. How should it look like?

How does it break the math? RSA can be decoded, we just don't have the processing power to do so yet IRL.

[Pleh]

An intrinsic problem of fantasy vs versimilitude.

What is RSA factoring if not simply the modern equivalent of the uncrackable code?

In fantasy, it could be actually uncrackable or practically uncrackable. In either case, an epic check could crack it unless it is actually impossible in thay campaign setting.

In which case magic can probably still crack it, of whatever spell level it needs.

My point is that RSA is only as tough to crack in D&D as the DM says it is.

[Grod_The_Giant]

Decipher Script is, I guess, the best skill we've got for codebreaking. So you've got two options: You can assign it a DC of your choice (and once you start getting into epic DC ranges, you're damn straight breaking the laws of the possible), or you can say "this code cannot be broken without magic." There's nothing in the rules that forces you to use one option or the other.

[Ashtagon]

"You can decipher writing in an unfamiliar language or a message written in an incomplete or archaic form. The base DC is 20 for the simplest messages, 25 for standard texts, and 30 or higher for intricate, exotic, or very old writing."

Neither SRD RAW nor plain English usage would allow for that skill to be used to perform cryptanalysis. By RAW it's only really for written languages that are actually intended to be human-readable without machine assistance.

Now, if you want to have that skill be used for cryptanalysis, be my guest. But that's not strict RAW.

[Deophaun]

Neither SRD RAW nor plain English usage would allow for that skill to be used to perform cryptanalysis.
Except for where it says you can use it for cryptanalysis:

You can use the Decipher Script skill to create a private cipher. This code system allows you (or anyone with the proper key) to record information without the risk of others reading it. Any document you create using your private cipher can be read only by you or someone who has the proper decoding information. Other characters with ranks in the Decipher Script skill can attempt to decipher the code. The DC for such a decoding attempt is 10 + your total skill modifier at the time that you create the cipher. (In effect, you “take 10” on a skill check to create the cipher, and those attempting to decode it make a Decipher Script check opposed by your take 10 result.)

[BaronDoctor]

DC 100-120 seems about right. Literally climbing up a flat, smooth wall or reading someone's mind via Sherlock Scan at 100 to moving through a Wall of Force at 120.

[Pleh]

Except for where it says you can use it for cryptanalysis:

Your quote is from Comp Adv?


Neither SRD RAW nor plain English usage would allow for that skill to be used to perform cryptanalysis. By RAW it's only really for written languages that are actually intended to be human-readable without machine assistance.

I didn't think Comp Adv was included in SRD. Thought that was the special "freebie content" which the "Complete X" books are not a part of?

[Malimar]

Your quote is from Comp Adv?

I didn't think Comp Adv was included in SRD. Thought that was the special "freebie content" which the "Complete X" books are not a part of?
The rules of the game are more than just the SRD. Each DM is free to decide what sources are and are not used at their table, but here in the Playground, the usual assumption is all first-party non-variant rules are available.

[martixy]

I'm already get used to fantasy games ignoring physics. But ignoring math is something new to me. And using decipher script to decode RSA with sufficiently high check breaks the math. How should I live with it?

I suppose if I need to forge fantasy version of math. How should it look like?

How is it breaking math? WE don't know if P=NP. It's an open problem.
Maybe it holds in D&D.

Also, RSA is a modern technology. It's on par with modern assault rifles. A lot of math had to come before it became viable, just like a lot engineering goes into modern weaponry.
Do you have automatic assault rifles in your D&D setting?

[Deophaun]

Your quote is from Comp Adv?

I didn't think Comp Adv was included in SRD. Thought that was the special "freebie content" which the "Complete X" books are not a part of?
It's a pointless limitation on the rules, like saying "Page 37 of the Fiend Folio doesn't say you can wield two weapons at the same time." Well, so what? Doesn't change the fact that elsewhere it says you can. So, get this, I ignored the arbitrary limitation that the OP did not include.

Furthermore,


Now, if you want to have that skill be used for cryptanalysis, be my guest. But that's not strict RAW.

This is Motte and Baileying. You have the Bailey--"that's not strict RAW,"--which, when breached, you then retreat to the Motte of "It's not in the SRD," and then claim that the indefensible position of the Bailey is thus validated.

[Ashtagon]

I find it interesting how almost everyone prefers to ignore that paragraph in Complete Warrior about prestige classes, or claim it only refers to CW prestige classes, or claim it is optional because reasons, but then people insist that a paragraph in Complete Adventurer must be in play at all times regardless.

To claim that this forum assumes all first part books are in play at all times is, from my observations, simply not true.

[ayvango]

DC 100-120 seems about right. Literally climbing up a flat, smooth wall or reading someone's mind via Sherlock Scan at 100 to moving through a Wall of Force at 120.
Ok, DC 100 for RSA1024. What DC should be for RSA2048 and RSA4096? It has exponential growth in complexity.

[ayvango]

Ashtagon: I'm basing the question on rules compendium, since it is easier to have all rules in the single book.

[ayvango]

Also, RSA is a modern technology.
Math is not technology it is just methodology of reasoning. All math ideas are hidden inside the simple axioms and deducing all consequences are just like remembering the whole idea existed regardless of any human brain describing it. The Plato gave that vision long ago.

[Ashtagon]

Ashtagon: I'm basing the question on rules compendium, since it is easier to have all rules in the single book.

Fair enough. But I see nothing in RC that allows a character to use RSA-style encryption. The skill lets you make a cipher. It doesn't let you make codes, let alone dual-key codes, and definitely not codes that require the amount of processing power available only in modern computers to encode.

But if you want to give the skill abilities beyond RAW, feel free.

[Deophaun]

Ok, DC 100 for RSA1024. What DC should be for RSA2048 and RSA4096? It has exponential growth in complexity.
Consider that the difference between a simpleton and a genius in D&D is a mere +7 modifier (Int of 6 versus an Int of 20) and you'll see that ability modifiers are also... well... nonlinear, at least. DC 110, DC 120.

I find it interesting how almost everyone prefers to ignore that paragraph in Complete Warrior about prestige classes, or claim it only refers to CW prestige classes, or claim it is optional because reasons, but then people insist that a paragraph in Complete Adventurer must be in play at all times regardless.
It's almost like the board is composed of individuals with their own individual minds, and not a Borg collective. Crazy, isn't it?

But, let's just throw this out there: did the OP say that he wasn't using the Completes? Did the OP say he wasn't using the RC? No?

Then why the hell did you think that was useful?

Do you often go around to other threads where people are suggesting something from the splats and shout "That's not RAW!" Is that a habit you subscribe to?

[Grod_The_Giant]

Math is not technology it is just methodology of reasoning. All math ideas are hidden inside the simple axioms and deducing all consequences are just like remembering the whole idea existed regardless of any human brain describing it. The Plato gave that vision long ago.
All of science is just a methodology of reasoning, and all principles of engineering and such exist regardless of whether humans know about them; it doesn't mean a character in a medieval setting can just build a car. Math and science are also cumulative processes, with generations of brilliant people building on each others' work, each advancing the frontiers of knowledge a little farther. You can't leapfrog that just because you, the player, know the end result.

EDIT: Also, and I see this reasonably often... you should notallow metagame science knowledge to overwrite the basic rules of the game. If the rules say "A DC 20 Craft (Explosives) check lets you make bombs that do 5d6 +1d6 per every 10 points you beat the DC," I don't care if you, the player, know how to make some sort of terrifying improvised C4 that "should" do way more damage, your bomb will do a base of 5d6. I'll give you a roleplaying bonus to your check because you thought it through and described it well, but that's it. Same goes for making a code-- you know about how RSA works, that's cool. I'll give you a +5 bonus to the decryption DC.

[Ashtagon]

Do you often go around to other threads where people are suggesting something from the splats and shout "That's not RAW!" Is that a habit you subscribe to?

If I was shouting, I would have used all caps.

[Deophaun]

The skill lets you make a cipher. It doesn't let you make codes...

cipher1
(also cypher)
NOUN

1A secret or disguised way of writing; a code.
‘he wrote cryptic notes in a cipher’
mass noun ‘the information may be given in cipher’
More example sentencesSynonyms
1.1 Something written in a code.
‘he came across ciphers written on parchment and concealed in a hollow altar pillar’
More example sentencesSynonyms
1.2 A key to a code.
Now, you have to ask yourself:

Are the rules written with a professional cryptographer in mind, and thus it is reasonable to assume that specialist definitions--precise to the field--are intended or...

Are the rules written for the layman, the everyman, who would consider "cipher" a synonym for "code," as the OED does?

[Ashtagon]

Fair point on the code/cipher bit. But I still don't see the rules letting you do something that under normal circumstances would require a modern computer to do (and mathematical theories that weren't known till 1978).

[Deophaun]

Fair point on the code/cipher bit. But I still don't see the rules letting you do something that under normal circumstances would require a modern computer to do (and mathematical theories that weren't known till 1978).
Yes, it would require a modern computer to do it under normal circumstances. That means it's actually a great deal more plausible for a skill check than something that simply cannot be done at all under normal circumstances, like balance on a cloud. So, regardless of the difficulty, it probably shouldn't exceed DC 120 (The balance check necessary to literally do the impossible).

[ayvango]

Consider that the difference between a simpleton and a genius in D&D is a mere +7 modifier (Int of 6 versus an Int of 20) and you'll see that ability modifiers are also... well... nonlinear, at least. DC 110, DC 120.

Non-linear, you are right. To be more precise - quadric. See prices for competence bonuses to skills. And square law abysmally lags of exponential. So it more like DC 250 and DC 1200.

[Deophaun]

Non-linear, you are right. To be more precise - quadric. See prices for competence bonuses to skills. And square law abysmally lags of exponential. So it more like DC 250 and DC 1200.
Except again, a DC 120 will allow you to do something physically impossible--allow a normal cloud to support your weight; no anti-gravity, no magnetic levitation--while decrypting an arbitrarily long RSA is possible given enough computing power. So, it should be less than 120.

The quadratic progression is just the pricing, not the capability.

[Ashtagon]

Yes, it would require a modern computer to do it under normal circumstances. That means it's actually a great deal more plausible for a skill check than something that simply cannot be done at all under normal circumstances, like balance on a cloud. So, regardless of the difficulty, it probably shouldn't exceed DC 120 (The balance check necessary to literally do the impossible).

Possible for a computer doesn't mean possible for a human. Especially not when the mathematical principles the code relies on haven't been invented yet (see Fantasy Gun Control for a related issue).

[ayvango]

Except again, a DC 120 will allow you to do something physically impossible
The problem is multiplication. You could do something physically impossible like jumping over the Atlantic ocean. Give any DC that you see appropriate for it. And how should the DC scale when you need to jump 100x times longer, effectively going to the Moon? And what if you would like to jump to the Jupiter? And what if you would like to perform interstellar travel with Jump check? Would you just add other 10 DC for each improvement?

[Pleh]

Jeezums, folks. It's just a game. RAW has no direct support, so the DC, if any, is whatever the DM says it is. That's all.

[johnbragg]

D&D universes do not operate according to real world laws of physics on anything but the most mundane scale. There are 4 elements, not around a hundred naturally occurring ones, the ability to bend spoons without touching them is unremarkable, the dead rising from their graves to feast upon the living is more common than tornadoes, etc.

So, yes, a character who can crank up DC 100 Decipher Script check can create PGP encryption, or its modern equivalent. Why? Because he's a huge badass and that's his specialty. If Chuck Norris is in your campaign world, and he is so inclined, he absolutely can divide by zero by delivering a roundhouse kick to the equation on a chalkboard.