Hermetic Encryption?

Games Discussion Ars Magica
1

It occurs to me that there are a few things - like the Parma Magica - where it would be very useful to have books available, such as a summa that will get you up to 3 ASAP if you want to Parma both a teacher and an apprentice, but where having books around risks letting stuff out of the Order.

So, my thought was, what about an encryption scheme that requires Hermetic magic to read?

So I came up with the following spell:

Rightful Seeker of Hermetic Knowledge

InTe(He) Level 35
Personal/Sun/Vision

This spell automatically decodes a specific cypher, chosen when the spell is learned(if the cypher is not pre-selected by the teacher or the text, the rules for it must be available while the magus is learning the spell). The meaning of the cyper is revealed effortlessly to the magus for the duration of the spell, permitting the study of texts using the cypher to conceal their contents.

(InTe base 4, +2 Sun, +4 Vision, +1 He requisite)

The cypher itself should be designed to be as hard as possible, and maybe also incorporate knowledge specific to the Order(like Magic Theory and Order of Hermes Lore) to make it really, really hard for outsiders to break the cypher mundanely.

For people who aren't InTe(He) experts, or who might be worried about the potential for warping from over-study, I imagine that a lens could be enchanted to do much the same thing, although in such a case it should have a linked trigger restricting it to members of the Order who haven't been Marched or something similar.

-Albert

2

No need for fancy encryption there. Just have the book written using a mundanely invisible ink, and overwritten with normal ink.

Then use a simple Intellego spell to see the invisible text (and make the normally visible one invisible).

Something like...

Reveal the Invisible Text
In(Pe)Im 10

This spell reveals the invisible text of a book, while making the normally visible text invisible. The spell fails to work if no invisible text is present.

(Base 2, +1 Touch, +2 Sun, +1 requisite)

3

Can be broken by anyone who can see invisible things. Such as anyone with Second Sight, or a member of any Gruagach-style tradition.

-Albert

4

I didn't mean invisible in a supernatural fashion. Mundanely transparent, for example quality linseed oil.

Second Sight allows you to see magically invisible stuff, not stuff that is naturally transparent.

5

I think a Watching Ward on the book to destroy it should it be opened by the wrong person (not a member of the Order of Hermes) - with attached InMe spell - would be the least complex method to secure its contents. Add a mundane lock to prevent 'accidental' destruction.

6

You'd have to throw a lot of penetration on the InMe (Nobles Parma on how that works with watching ward) or warn Magi to drop their Parma before reading. Which might be taken the wrong way when you think about it.

I might go with a Teleport to a safe location effect over a destroy the book effect. Or possibly enchant in some sort of PeMe effect that makes it impossible to understand the book. One that targets the reader not the book. Even a PeIg effect that eliminates all light near the book.

7

And we're back to my argument about how the order would be better served using Order of Hermes lore to make themselves a grand scale mystery cult.

8

Anyone who should be opening the book will know of its requirements. If they're that paranoid, they can dispel the Watching Ward. Heck, for really important books, the would be enchanted with multiple effects (and high Penetration) to safeguard the knowledge.

9

The other option being that Parma books teach 99% of Parma - and that the final hand sigil to turn it on isn't listed. This is how Apprentices describes teaching Parma - children are actually taught it throughout their apprenticeship, but they don't know the final key sigil until after their Gauntlet.

Which admittedly isn't that great a way to keep a secret (as it could be ripped/coerced out of the mind of a magus by the appropriate Hedge Magician effect), but it does at least add a level of security.

10

If someone already has Parma, that would probably be sufficient justification to let them read the book. So you'd really only need 10-15 levels of penetration. Any more than that, and they're probably a Hermetic magi anyway.

And in terms of mentally scanning a wizard, it seems that the question is "are you a hermetic magi" - which is probably something most Tribunals are OK with hermetic magi confirming. As such, like the "Are you Gifted" question, it's likely not a proscecutable offense in most locales.

EDIT - I suppose an easier one would be an InVi - "do you have a Parma up" - which would suffice for most folks. (Except of course, an apprentice who wants to read the text.) Or even "have your Arts been Opened" - which apparently can also be detected via InVi magic.

11

Sure but you have to see what an obvious potential for a trap such a book has. You can dispel the watching ward if your suspicions but they aren't free. You also don't have to place your trap on the book if you have access to where you know the book will be read.

12

I was thinking about this too, and was looking at magical encryption and protection of spell books in a blog post.

My thinking was to actually perform the encryption properly using Imagonem, and base it upon the Caesar shift algorithm or a scytale as examples of simple ciphers. The Cipher of Trianoma (see HoH: TL, p20-21) is an example of a very simple cipher.

My character in a current pbp game has an effect to conjure an illusion upon a page to protect the information. Not at all perfect, and not a proper form of encryption at all, but it will fool a mundane or even a magus who is not aware of what they are really looking at. It saved from introducing the argumentative topics which arise when more modern crypto is used along side magic.

When we talked about it the forums a while ago there was an opinion raised about the magi of the time being incapable of development more advanced crypto techniques, as the thinking was too advanced (in the spirit of mathematical processing, not that they were fools). For example the Enigma machine in WWI wasn't much more than a shifting substitution cipher, combined with a permutation cipher. The complexity of the ciphers was alleviated by the machine, which is why getting an Enigma was so critical to breaking it's use.

I argue that a magi can use magic to apply multiple complex layers of crypto just as the enigma could, and the thinking in the medieval period does not allow for that thinking in the same way as it didn't allow for Rego magic to accelerate manual work.

Some other things that magi's crypto could do is use the Bloodline of the magus. Or alter the Magi's mind so that all work is written pre-encrypted automatically (using a prescribed cipher).

I went as far to suggest guidelines of difficulty for magical crypto, but I've never used it in play. I'd love to though.

The post should also have some suggestions on how to crack the ciphers manually (with respect to HoH:TL's suggestions)

13

There is a section in Transforming Mythic Europe about how magic can neither read not understand. Basically, Intellego can be used to acquire information, but it is not the art of information itself. I don't believe it can be used in this manner because of this. Intellego cannot understand the words on a written page even if not encrypted. I suspect other ways of hiding information (as suggested elsewhere in this thread) might be a better way to go.

Another thought: write your words with a plant-based ink, then write nonsense over the top (or paint) with a mineral-based ink. The book can then be read with a spell that leaves your senses unhindered by earth (an InTe spell). There are numerous variants here.

Mark

14

How good was medieval encryption anyway?

I guess the technology was around for one time pads but goodness knows if anyone actually used them.

I know that certain basic ciphers were common, substitution ciphers notable. Julius Caesar is rumoured to have encrypted his communicaes with the cipher now know as the Caesar cipher, but these were basic and wouldn't stop a skilled cryptanalyst. Although I'm also not sure how good cryptanalysis was at this time either.

Anyone know much about medieval cryptography?

15

I like the idea a LOT. The perfect solution to so many Hermetic security problems.

Yeah, it was all very basic. Most anyone on these boards could spend an hour learning the techniques, and a day to crack most any Medieval cypher.

It wasn't until the 20th century that codes started using complex math (if at first in the form of machines, ala Enigma) to make things more difficult, but even those proved crack-able with enough brute force.

But this isn't a cypher - it's a code.

the word "blue" = "Hermetic" - that's not crackable, no matter how much time you spend.

The OP was not suggesting that the spell do the brute-force decoding from the unknown pages, but that the specific code was pre-existing as part of the specific spell effect - a simple "decoding" table if you will.

All the spell does is take the place of a (very complex) Code book, with all values known and fixed when the spell is invented/learned. The effect is cast, the pre-determined values are substituted - voila.

Now, that said, MS is correct - Intellego is not the correct Technique, as nothing is being "perceived" here, or at least nothing that can be from the Caster's point of view (i.e. the full Code is not on the page, only one encoded half of it). What is needed is a MuMe effect, so what the caster reads on the pages in front him them will mean something different.

MuMe 5
Magic Decoder Ring
R: Pers, Dur:Ring , T:Ind

Changes the understood meaning of written words to a pre-determined alternative for the duration of the effect. If that existing Code is not known, or different than expected or inaccurately coded, the result is gibberish. It is impossible to independently invent this effect without having full access to that specific Code, but the effect can be taught or learned from lab texts without that knowledge.

As the effect is magical, the Code itself is abstract and cannot be broken by conventional means, no matter how complex or advanced the effort.

(An identical level effect has the Duration as Sun, and this effect allows reading of that code all day long, but anything else that is read will be gibberish unless the effect is dispelled.)

(Base 2: Major Change in Memory (of written words' meanings), +0 Personal, +2 Ring (or Sun), +0 Individual, +1 complexity "just because")

A typical MuMe 5 effect could easily be spont'ed - however this is not typical. The obstacle to doing so casually is that the exact code is unknown and unlearn-able from the text itself (and unless someone knows the Code (or is using an InMe to refresh a past memory of it), sponting the spell accurately would be impossible. Without knowing that key when the spell is cast - or invented - the Muto effect might as well be random.

16

when I wrote the blogpost linked above, I took the same approach, but a base as 3 and additional complexity for allowing the cipher to be altered per casting, and a lot of additional mags to represent the complexity in what the spell has to do with the memory/mind of the target. Adding +3 mags total is probably overkill, but I'm not sure base 2 is complex enough by itself.

Subversion of the Magister’s Mind
Muto Mentum 20, R: Personal, D: Sun, T: Individual

For the duration of the all material written by the target is automatically encrypted with the chosen cipher key. If for whatever reason the target must write clearly and legibly, the task is as difficult as reversing the cipher key on the fly; which should be a very difficult or almost impossible task.

This effect allows for the cipher key to be declared when the effect is cast, and the cipher may be complex in nature. The effect has no impact to material spoken or read, events perceived, or other interaction.

(Base 3 as effect is estimated as equivalent to “Make a major change in a person’s memory of a series of events”, +2 Duration to Sun, +2 to use a complex cipher, +1 to allow cipher declared when cast)