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MuWire Web-Of-Trust
The Gnutella protocol is very efficient at keyword search, but it is very exposed to fakes and viruses. To control the spread of such files, MuWire introduces the concept of Web-Of-Trust on top of its Gnutella-like topology.
Definition of a Persona
MuWire assumes that each human user is going to have a single persona. A persona consists of the following two items:
- An I2P destination - this is the destination where the MuWire node is listening for incoming requests.
- A human-readable nickname
The nickname and the I2P destination are signed by the signing key which is part of the destination. This is to provide assurance that the owner of the private key is the one who has chosen the nickname.
For UI purposes, the persona will be displayed as the human-readable nickname plus '@' followed by the first 32 bytes of the b32 I2P address derived from the b64 destination. The intention is to make it easier for users to differentiate between personas, but at the same to prevent spoofing of personas through mass generation of I2P destinations.
Trusting other personas
Trust between personas is only built manually as a result of user action in the UI. Trust is never established automatically to prevent gaming the system. Whenever a search result is displayed to the user, the persona of the responder is displayed as well. The user then has the choice to trust or distrust the sender of the search result.
In order for that to work it is necessary that search results carry the complete persona of the responder. Since they are returned via the I2P streaming library, the I2P address of the responder is already known and verified to be valid.
Users are encouraged to only trust after successfully downloading a file and verifying that it is genuine. Future search results from trusted personas are highlighted in the UI and users are encouraged to download them instead of untrusted ones. This helps control the spread of viruses and fake files.
Sharing trust lists
In order to enable users to make better choices whom to trust, the protocol allows for exchange of trust lists. Users can query the trust lists of other personas through an UI action. There are two types of queries - "who do you trust" and "who trusts you" which are executed as GET requests to the I2P address of the persona being queried
"Who do you trust" query
The response is a list of full persona details that the responder currently trusts.
"Who trusts you" query and certificates
This query is more informative when making the decision whether to trust, so it is important for it to be more difficult to abuse. To provide such protection, the response body contains trust "certificates" instead of raw personas.
Definition of a trust certificate
A trust certificate is a signed document stating that Alice trusts Bob. Charlie can verify that trust even if he does not know anything about Alice or Bob. To make that possible, a trust certificate contains:
- Alices' persona details
- Bob's persona details
- Timestamp of the creation of the certificate
- Alices' signature of the above items.
The timestamp serves only informational purposes, i.e. there is no built-in expiration of certificates in the protocol. Different UI implementations however may choose to treat different certificates differently based on their age.
Propagation of trust certificates in the network
Trust certificates are generated whenever a user chooses to trust someone. That action triggers the creation of the certificate and the upload of the certificate via a POST call to the MuWire node running the persona being trusted.
The other method of propagation is the "Who trusts you" query. Since the certificate contains full persona details of the trustee, it enables the user to "crawl" the trust graph of the network without issuing search queries.