Dining cryptographers protocol
Imagine you are at a restaurant with two of your friends. You all want to order something to eat, but you also want to keep your orders a secret from each other and from anyone else who might be listening. The Dining Cryptographers Protocol is like a game you can play to keep your orders secret.
First, everyone decides on a secret message that they want to send. This could be their order, like "I want spaghetti," or it could be a secret code that only they know the meaning of.
Next, everyone puts their message into a napkin or envelope and passes it to the person sitting next to them. Then, each person looks at their own message and decides whether to add a secret "key" to it or not.
The key is just a random number that has been agreed on beforehand. If someone adds the key to their message, they write "Yes" next to it. If they don't add the key, they write "No" next to it.
Once everyone has decided whether to add the key or not, they pass their napkin or envelope to the person next to them again. This time, the person looks at the message and the key (if there is one) and does the following:
- If there is no key, they simply pass the message on to the next person
- If there is a key and it says "Yes," they add the key to their own message and write "Yes" as well
- If there is a key and it says "No," they don't add the key to their own message and write "No" as well
This goes on until everyone has seen and added or not added the key to each message. Then, everyone opens up their napkins or envelopes and reads the messages.
If someone added the key to their message and wrote "Yes," it means they want the message to be "true" and count as part of the conversation. If they wrote "No," it means they want the message to be "false" and not count.
When everyone reads the messages together, they can tell which messages were "true" and which were "false" based on whether anyone added a key to them. But because there are multiple messages with keys and some without, it's hard for anyone listening in to know exactly what each person's order or message was.
In summary, the Dining Cryptographers Protocol is a fun way to keep messages secret by using keys and passing around notes. Just like keeping your food orders secret from your friends at a restaurant!
First, everyone decides on a secret message that they want to send. This could be their order, like "I want spaghetti," or it could be a secret code that only they know the meaning of.
Next, everyone puts their message into a napkin or envelope and passes it to the person sitting next to them. Then, each person looks at their own message and decides whether to add a secret "key" to it or not.
The key is just a random number that has been agreed on beforehand. If someone adds the key to their message, they write "Yes" next to it. If they don't add the key, they write "No" next to it.
Once everyone has decided whether to add the key or not, they pass their napkin or envelope to the person next to them again. This time, the person looks at the message and the key (if there is one) and does the following:
- If there is no key, they simply pass the message on to the next person
- If there is a key and it says "Yes," they add the key to their own message and write "Yes" as well
- If there is a key and it says "No," they don't add the key to their own message and write "No" as well
This goes on until everyone has seen and added or not added the key to each message. Then, everyone opens up their napkins or envelopes and reads the messages.
If someone added the key to their message and wrote "Yes," it means they want the message to be "true" and count as part of the conversation. If they wrote "No," it means they want the message to be "false" and not count.
When everyone reads the messages together, they can tell which messages were "true" and which were "false" based on whether anyone added a key to them. But because there are multiple messages with keys and some without, it's hard for anyone listening in to know exactly what each person's order or message was.
In summary, the Dining Cryptographers Protocol is a fun way to keep messages secret by using keys and passing around notes. Just like keeping your food orders secret from your friends at a restaurant!