Difference between revisions of "Knowledge skill"
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#* Base DC: 20 | #* Base DC: 20 | ||
#* These methods are not really used (or needed) by most peope. Many don't even know they exist or how they work. | #* These methods are not really used (or needed) by most peope. Many don't even know they exist or how they work. | ||
#* Unless | #* Unless a cipher is available, the encryption cannot be broken. | ||
#* Takes a very long time to decode, even with | #* Takes a very long time to decode, even with cipher and needs notes or other tools. | ||
# '''Very hard:''' [[wikipedia:Polyalphabetic_cipher|Polyalphabetic cipher]] | # '''Very hard:''' [[wikipedia:Polyalphabetic_cipher|Polyalphabetic cipher]] | ||
#* Base DC: 15 | #* Base DC: 15 | ||
#* Less wieldly and the recipient needs to already have a | #* Less wieldly and the recipient needs to already have a cipher for effective decryption. | ||
#* Messages can be broken without | #* Messages can be broken without ciphers, but it's hard. | ||
#* Takes a long time to decode. | #* Takes a long time to decode without cipher. | ||
# '''Hard:'''[[wikipedia:Substitution cipher|Substitution cipher]] or [[wikipedia:Transposition cipher|Transposition cipher]] | # '''Hard:'''[[wikipedia:Substitution cipher|Substitution cipher]] or [[wikipedia:Transposition cipher|Transposition cipher]] | ||
#* Base DC: 5 | #* Base DC: 5 | ||
#* Most common encryption of this time. Makes sure uninitiated can't read it and delays the time it takes for others to do so. | #* Most common encryption of this time period. Makes sure uninitiated can't read it and delays the time it takes for others to do so. | ||
#* Messages can be broken without | #* Messages can be broken without ciphers, but the decoder needs some specialist skill. | ||
#* Can be decoded without any additional tools and fairly quickly. | #* Can be decoded without any additional tools and fairly quickly. | ||
# '''Code:''' Simply | # '''Code:''' Simply a matter of writing with replaced words or innuendos. More of a Linguisitc, Bluff or Sense Motive roll than Mathematics, etc. | ||
#* Depends on coder's Bluff check. | #* Depends on coder's Bluff check. | ||
The character needs to have a total bonus that is higher or equal to the base DC of a cryptography method to use it. | |||
The character needs to have a total bonus that is higher or equal to the base DC of a cryptography method to use it | |||
=== Create Cipher === | |||
A cipher is the 'key' to an encryption. It can be used for any number of messages. | |||
To encrypt a message the cryptographer needs to choose a method and make a cipher. When method is chosen she then decides if she wants to modify the base DC further (See table). A character makes an appropriate skill check against the modified DC to see how long time it takes. The creation takes a number of minutes equal to the modified DC of the encryption method, minus 1 for every point rolled over the DC. If the result would reduce the time to between 0 and -5 minutes, it instead takes 30 seconds. If the result reduced the time to less than -5 minutes, it instead takes 6 seconds (1 full-round action). | |||
If she fails the check by 5 or less, her messages will have bits of gibberish in it (GM's discretion) but a fail by more than 5 will just create incoherent messages, even with the cipher to decode it. | |||
=== Encrypt Message === | |||
When a character has made a cipher, she rolls to encrypt a message using this cipher. She makes an appropriate skill check against the modified DC. If she suceeds, she writes the encrypted text in the standard time it would take but if she fails by less than 5, she has made an error and realises she needs to start over. If she fails by more than 5, she doesn't notice the error and the message is altered (at GM's discretion; most likely making a some part undecipherable). | |||
The time it takes to encrypt the message is decided by multipying the modified DC with the length of the message in minutes. Each quarter of a page counts as 1 in this equation, and minimum one quarter page message is calculated for the time. For every point of the skill check result above the DC, the time to encrypt is reduced by 1 minute. If the result would reduce the time to 0 or less, it instead takes 30 seconds. | |||
=== Decrypt a Message === | |||
Revision as of 13:20, 17 September 2015
The Knowledge skill in DnD and Pathfinder is an important skill in Hökaland. This article provides some guidelines on how to use the skill with information in this wiki.
Cryptography
Knowledge (Mathematics) and Craft (Cryptography) or Profession (Cryptographer) can be used to decipher deliberately encrypted written messages. While Linguistics is used to decipher actual information from messages, cryptography is a very deliberate and specific skill. Mathematics skills are always useful, but a character can only receive a bonus from either her skill i ncraft or her profession.
Skill ranks in either mathematics or encryption (either craft or profession) can be combined up to 1½ the number of HD a character has (round down). The character still has to choose to use either Knowledge (Mathematics), Craft (Cryptography) or Profession (Cryptographer) for the actual skill check, however. This means the ability modifier and special bonuses only applies once and only for the skill selected.
A character cannot attempt to decipher a coded message untrained unless she has clear instructions she can follow, and then make an intelligence check assisted by the encryption bonus provided by the instructions.
Example: Exarch the wizard is trying to decipher a message he has intercepted. He is his Circle's cryptographer (Profession (Cryptography)) and is very good at mathematics at level 8. He first adds together his 8 skill ranks in Knowledge (Mathematics) and 8 ranks in Profession (Cryptography), getting a total of 16. However, he has a total of 8 HD, so the maximum skill rank bonus is 12 and she chooses to use Knowledge (Mathematics) for the roll, adding her Class Skill bonus and Skill Focus bonus. This total skill rank bonus of 12 is then combined with his Intelligence bonus of 4, Class Skill bonus of 3 and Skill Focus bonus of 3: 12 + 4 + 3 + 3 = 22. He then adds +22 to his decipher roll.
Choose Encryption
When making an encrypted message, there are a number of techniques one can choose from; each have advantages and disadvantages. If the logistics of ciphers and methods between the sender and recipient is dealt with, the main difference between methods is the time it takes to decipher the message. For the use of rules in Hökaland there are three categories:
- Impossible: One Time Pad or Running Cipher
- Base DC: 20
- These methods are not really used (or needed) by most peope. Many don't even know they exist or how they work.
- Unless a cipher is available, the encryption cannot be broken.
- Takes a very long time to decode, even with cipher and needs notes or other tools.
- Very hard: Polyalphabetic cipher
- Base DC: 15
- Less wieldly and the recipient needs to already have a cipher for effective decryption.
- Messages can be broken without ciphers, but it's hard.
- Takes a long time to decode without cipher.
- Hard:Substitution cipher or Transposition cipher
- Base DC: 5
- Most common encryption of this time period. Makes sure uninitiated can't read it and delays the time it takes for others to do so.
- Messages can be broken without ciphers, but the decoder needs some specialist skill.
- Can be decoded without any additional tools and fairly quickly.
- Code: Simply a matter of writing with replaced words or innuendos. More of a Linguisitc, Bluff or Sense Motive roll than Mathematics, etc.
- Depends on coder's Bluff check.
The character needs to have a total bonus that is higher or equal to the base DC of a cryptography method to use it.
Create Cipher
A cipher is the 'key' to an encryption. It can be used for any number of messages.
To encrypt a message the cryptographer needs to choose a method and make a cipher. When method is chosen she then decides if she wants to modify the base DC further (See table). A character makes an appropriate skill check against the modified DC to see how long time it takes. The creation takes a number of minutes equal to the modified DC of the encryption method, minus 1 for every point rolled over the DC. If the result would reduce the time to between 0 and -5 minutes, it instead takes 30 seconds. If the result reduced the time to less than -5 minutes, it instead takes 6 seconds (1 full-round action).
If she fails the check by 5 or less, her messages will have bits of gibberish in it (GM's discretion) but a fail by more than 5 will just create incoherent messages, even with the cipher to decode it.
Encrypt Message
When a character has made a cipher, she rolls to encrypt a message using this cipher. She makes an appropriate skill check against the modified DC. If she suceeds, she writes the encrypted text in the standard time it would take but if she fails by less than 5, she has made an error and realises she needs to start over. If she fails by more than 5, she doesn't notice the error and the message is altered (at GM's discretion; most likely making a some part undecipherable).
The time it takes to encrypt the message is decided by multipying the modified DC with the length of the message in minutes. Each quarter of a page counts as 1 in this equation, and minimum one quarter page message is calculated for the time. For every point of the skill check result above the DC, the time to encrypt is reduced by 1 minute. If the result would reduce the time to 0 or less, it instead takes 30 seconds.
Decrypt a Message
Notation
As far as possible, each part of the wiki will be marked with a floating information box, indicating the Difficulty Class (DC) for a character to know a particular piece of information.
Alternate knowledge
On many occasions, another Knowledge skill can be constituted by another skill. For example, knowing who the local regent's son is may normally be a roll for Knowledge (Nobility), but a character with good local knowledge could make a Knowledge (Local) at a slightly higher DC.
Synergy
A character may request to have a small situational bonus to a roll if she has knowledge skill bonuses in more than one related skill. For instance, checking to see if a character knows whether or not a specific noble is religious where both skills in nobility and religion are high, you pick one and get a small bonus. This bonus does not count intelligence modifier twice. Check with your DM if you are allowed synergy bonus.
- Synergy: For every 3 points of total bonus, you can use one point of situational bonus on the roll.
Faction knowledge rolls
Living in the world, characters will know some things and not others. This is a guide to DC levels for what type of information they require regarding a particular faction.
* Only applies to the right type of knowledge skill.
Recognising the name
- All Court of Houses members - (history)/(local)/(nobility) DC5.
- Other houses - (local) DC15, (nobility) DC8.
- Main factions - (history)/(local)/(religion*) DC5.
- Other factions - (history) DC15, (local) DC8.
- If rolling right type of knowledge skill: DC8.
Basic
For basic information about the individual faction, such as key aims and strengths (in general), shield, rough size estimates and current (or most recent) leader:
- Governor - (local)/(nobility) DC10.
- Court of Houses Member - (local) DC15, (nobility) DC10.
- Other houses - (local) DC20, (nobility) DC15
- Main factions - (history) DC15, (local)/(religion*) DC10.
- Other factions - (history) DC20, (local) DC15.
- If rolling right type of knowledge skill: DC15.
Details
Detailed information such as relationships with other factions or current rough economic status and exports:
- Court of Houses Members - (local) DC20, (nobility) DC15.
- Other houses - (local) DC25, (nobility) DC20.
- Main factions - (history) DC25, (local)/(religion*) DC15.
- Other factions - (history) DC30, (local) DC20.
- If rolling right type of knowledge skill: DC20.
Inside Story
Inside information such as total military strength, specific cash flow and individual staff members:
- All Court of Houses Members - Knowledge (local) DC25, Knowledge (nobility) DC20.
- Other houses - Knowledge (local) DC30, Knowledge (nobility) DC25.
- Main factions - (local) DC25, (religion*) DC20.
- Other factions - (local) DC30.
- If rolling right type of knowledge skill: DC25.