D&D 5E A Beautiful Mind: Breaking the Code...

[WarpedAcorn]

My players have received a journal from one of the bad guy's acolytes except, oh no, its written in code they can't decipher. I know that Comprehend Languages does not translate code, but are there any other spells that might accomplish this?

Also, if my players wanted to take a crack at it, what checks would you make and what timeline do you think we would be looking at? I'm pretty sure it would have to be an Int check, maybe Investigation?

 

[aco175]

How hard you make it depends on what you want the outcome to be. If you want to get to the next part of the adventure and have the PCs go there soon you can give it an DC15 Investigation check and one of the characters should pass. You can also have them in town and just say that they find a sage who translates it for 10gp, done.

You could also take it and run for more adventure and intrigue. Make the DC really high like 30 so they need to get assistance by going to a temple, or sage. Make an adventure about looking for a place with secret code-breaking scrolls. You can have cool new NPCs and more cultists attacking to recover the scroll. A guide NPC who is a traitor and leads them to an underground temple that is a trap,but gives them a clue to the next piece of the adventure. You can have this side adventure take a few sessions of play before moving onto the next more scripted adventure.

I cannot think of a specific spell, but you could have a temple, perhaps to a magic or knowledge god, cast some sort of ritual and make the words become normal. It is not a spell a PC can use, but there can be magic that NPCs can use and PCs do not have.

 

[MonkeezOnFire]

The linguist feat models this and you can look to it for inspiration. Its a straight intelligence check to attempt to solve it and the DC is based on the intelligence modifier of the person that wrote it.

 

[FormerlyHemlock]

A brain-dead stupidly simple code could be as low as DC 20.

A good code would be impossible (no DC, totally infeasible). That's the whole point of a code.

 

[iserith]

A character with the Linguist feat can create ciphers; this may reasonably grant advantage on checks to decipher the codes of others. I can't think of any spells that serve this purpose.

A timeline for cracking the code is only useful if time is actually valuable. If they have all the time in the world to figure it out, then just give them automatic success. If time is short, then that suggests some meaningful chance of failure and an ability check may be appropriate. An Intelligence check seems like the applicable mechanic, though you may decide another ability or skill applies based on the player's stated approach. It's important in my view to hear HOW the player plans on having the character crack the code before deciding on the best mechanic to resolve the uncertainty of the attempt. A successful check might mean deciphering the journal in good time; a failed check might mean taking longer than desired which results in some consequence that complicates the PCs achieving their goals.

This may also be a good opportunity to give them automatic success, but at a cost, such as by needing to consult an NPC expert in such matters who requires payment in the form of gold or service.

 

[Raunalyn]

I would make it an investigation check. The difficulty would be set by the complexity of the code...if it's time sensitive, I would determine the speed of the translation by how successful they are on the Investigation check.

I don't have my PhB with me, but can Tongues translate ciphers?

 

[TheEvilDM]

I'd say it depends on who created the code and for what purpose.

Was the creator particularly intelligent or practiced in creating ciphers? For whom was it made? Was it a simple message or something more important? How would the receiving party have decoded the message? If you need a key to decipher the code, it's probably undoable to crack it by hand; however, that means a key must be available somewhere and they could search for it. If, on the other hand, it uses a simple substitution rule (like ROT13), it'd be a piece of cake for anyone who's ever done anything with code. You start by looking for the most common letters and words, and work from there. That really shouldn't take more than an hour at most, and not require a check. If none of the PCs have any reasonable experience with ciphers, they could hire someone.

Hope this helps, if you have some additional information about the code or further questions, I'd be happy to offer my insights!