Riffle (anonymity network)

Riffle is an <a href="/facts/Anonymity_network/ArhwQE74">anonymity network</a> developed by researchers at <a href="/facts/Massachusetts_Institute_of_Technology/Xk49vNA8">MIT</a> and <a href="/facts/%25C3%2589cole_Polytechnique_F%25C3%25A9d%25C3%25A9rale_de_Lausanne/IBPANwjM">EPFL</a> as a response to the problems of the <a href="/facts/Tor_(anonymity_network)/Wj6jjkx1">Tor network</a>. 
Riffle employs a <a href="/facts/Privacy/C269YalS">privacy</a>-enhancing <a href="/facts/Communication_protocol/5uady7cB">protocol</a> that provides strong <a href="/facts/Anonymity/HUJJCdv1">anonymity</a> for secure and anonymous communication within groups. The protocol is designed using the anytrust model, which ensures that even if colluding <a href="/facts/Server_(computing)/dEaYFD7r">servers</a> attempt to compromise the privacy of the group, they cannot do so if at least one server in the group is honest.
Like Tor, it utilizes <a href="/facts/Onion_routing/L1SKrFGc">onion routing</a>. According to MIT's Larry Hardesty, researchers at MIT and the <a href="/facts/Qatar_Computing_Research_Institute/QznjuLUJ">Qatar Computing Research Institute</a> demonstrated a vulnerability in Tor's design.
To achieve its goals, Riffle implements two distinct protocols: the Hybrid Shuffle protocol for sending and <a href="/facts/Private_Information_Retrieval/1obgRnP7">Private Information Retrieval</a> (PIR) for receiving.
For sending information, Riffle uses a hybrid shuffle, consisted of a verifiable shuffle and a <a href="/facts/Symmetric-key_algorithm/5zfe0b76">symmetric-key algorithm</a>. The Hybrid Shuffle protocol consists of a setup phase and a transmission phase. During the setup phase, a slow verifiable shuffle based on <a href="/facts/Public-key_cryptography/gowoFTxS">public key cryptography</a> is used, while an efficient shuffle based on <a href="/facts/Symmetric-key_cryptography/5zfe0b76">symmetric key cryptography</a> is used during the transmission phase. Messages sent over Riffle are not forwarded if they have been altered by a compromised server. The server has to attach <a href="/facts/Zero-knowledge_proof/38soaPT5">proof</a> in order to forward the message. If a server encounters <a href="/facts/Authentication_protocol/pcX97lnA">unauthenticated</a> messages or different permutations, it exposes the <a href="/facts/Digital_signature/tY7e2pnW">signed</a> message of the previous server and runs the accusation protocol to ensure <a href="/facts/Authentication/64y4S69b">verifiability</a> without requiring computationally intensive protocols during transmission phases.
For receiving information it utilizes multi-server <a href="/facts/Private_information_retrieval/1obgRnP7">Private Information Retrieval</a>. All servers in the system share a <a href="/facts/Replicated_database/QIaooMjL">replicated database</a>, and when a <a href="/facts/Client%25E2%2580%2593server_model/FSnf27C5">client</a> requests an entry from the <a href="/facts/Database/VYcpkevb">database</a>, they can cooperatively access it without knowing which entry they are accessing.

The main intended <a href="/facts/Use_case/8pNHjsIr">use-case</a> is anonymous <a href="/facts/File_sharing/7GISy0GJ">file sharing</a>. According to the lead project researcher, Riffle is intended to be complementary to Tor, not a replacement.

Riffle (anonymity network) open-in-new

Riffle (anonymity network)