torspec/proposals

Tor proposals by status

Here we have a set of proposals for changes to the Tor protocol. Some of these proposals are implemented; some are works in progress; and some will never be implemented.

Below are a list of proposals sorted by status. See INDEX.md for a list of proposals sorted by number.

Active proposals by status

OPEN proposals: under discussion

These are proposals that we think are likely to be complete, and ripe for discussion.

• 239-consensus-hash-chaining.txt: Consensus Hash Chaining
• 240-auth-cert-revocation.txt: Early signing key revocation for directory authorities
• 267-tor-consensus-transparency.txt: Tor Consensus Transparency
• 277-detect-id-sharing.txt: Detect multiple relay instances running with same ID
• 287-reduce-lifetime.txt: Reduce circuit lifetime without overloading the network
• 295-relay-crypto-with-adl.txt: Using ADL for relay cryptography (solving the crypto-tagging attack)
• 296-expose-bandwidth-files.txt: Have Directory Authorities expose raw bandwidth list files
• 303-protover-removal-policy.txt: When and how to remove support for protocol versions
• 306-ipv6-happy-eyeballs.txt: A Tor Implementation of IPv6 Happy Eyeballs
• 308-counter-galois-onion.txt: Counter Galois Onion: A New Proposal for Forward-Secure Relay Cryptography
• 309-optimistic-socks-in-tor.txt: Optimistic SOCKS Data
• 315-update-dir-required-fields.txt: Updating the list of fields required in directory documents
• 319-wide-everything.md: RELAY_FRAGMENT cells
• 321-happy-families.md: Better performance and usability for the MyFamily option (v2)
• 322-dirport-linkspec.md: Extending link specifiers to include the directory port
• 323-walking-onions-full.md: Specification for Walking Onions
• 324-rtt-congestion-control.txt: RTT-based Congestion Control for Tor
• 325-packed-relay-cells.md: Packed relay cells: saving space on small commands
• 326-tor-relay-well-known-uri-rfc8615.md: The "tor-relay" Well-Known Resource Identifier
• 330-authority-contact.md: Modernizing authority contact entries
• 332-ntor-v3-with-extra-data.md: Ntor protocol with extra data, version 3
• 334-middle-only-flag.txt: A Directory Authority Flag To Mark Relays As Middle-only
• 335-middle-only-redux.md: An authority-only design for MiddleOnly
• 336-randomize-guard-retries.md: Randomized schedule for guard retries
• 337-simpler-guard-usability.md: A simpler way to decide, "Is this guard usable?"

ACCEPTED proposals: slated for implementation

These are the proposals that we agree we'd like to implement. They might or might not have a specific timeframe planned for their implementation.

• 265-load-balancing-with-overhead.txt: Load Balancing with Overhead Parameters
• 275-md-published-time-is-silly.txt: Stop including meaningful "published" time in microdescriptor consensus
• 285-utf-8.txt: Directory documents should be standardized as UTF-8
• 288-privcount-with-shamir.txt: Privacy-Preserving Statistics with Privcount in Tor (Shamir version)
• 292-mesh-vanguards.txt: Mesh-based vanguards
• 311-relay-ipv6-reachability.txt: Tor Relay IPv6 Reachability
• 312-relay-auto-ipv6-addr.txt: Tor Relay Automatic IPv6 Address Discovery
• 313-relay-ipv6-stats.txt: Tor Relay IPv6 Statistics

FINISHED proposals: implemented, specs not merged

These proposals are implemented in some version of Tor; the proposals themselves still need to be merged into the specifications proper.

• 160-bandwidth-offset.txt: Authorities vote for bandwidth offsets in consensus
• 232-pluggable-transports-through-proxy.txt: Pluggable Transport through SOCKS proxy
• 260-rend-single-onion.txt: Rendezvous Single Onion Services
• 282-remove-named-from-consensus.txt: Remove "Named" and "Unnamed" handling from consensus voting
• 301-dont-vote-on-package-fingerprints.txt: Don't include package fingerprints in consensus documents
• 310-bandaid-on-guard-selection.txt: Towards load-balancing in Prop 271
• 314-allow-markdown-proposals.md: Allow Markdown for proposal format
• 333-vanguards-lite.md: Vanguards lite

META proposals: about the proposal process

These proposals describe ongoing policies and changes to the proposals process.

• 000-index.txt: Index of Tor Proposals
• 001-process.txt: The Tor Proposal Process
• 098-todo.txt: Proposals that should be written
• 099-misc.txt: Miscellaneous proposals
• 202-improved-relay-crypto.txt: Two improved relay encryption protocols for Tor cells
• 257-hiding-authorities.txt: Refactoring authorities and making them more isolated from the net
• 290-deprecate-consensus-methods.txt: Continuously update consensus methods

INFORMATIONAL proposals: not actually specifications

These proposals describe a process or project, but aren't actually proposed changes in the Tor specifications.

• 159-exit-scanning.txt: Exit Scanning
• 300-walking-onions.txt: Walking Onions: Scaling and Saving Bandwidth

Preliminary proposals

DRAFT proposals: incomplete works

These proposals have been marked as a draft by their author or the editors, indicating that they aren't yet in a complete form. They're still open for discussion.

• 273-exit-relay-pinning.txt: Exit relay pinning for web services
• 294-tls-1.3.txt: TLS 1.3 Migration
• 316-flashflow.md: FlashFlow: A Secure Speed Test for Tor (Parent Proposal)
• 327-pow-over-intro.txt: A First Take at PoW Over Introduction Circuits
• 329-traffic-splitting.txt: Overcoming Tor's Bottlenecks with Traffic Splitting
• 331-res-tokens-for-anti-dos.md: Res tokens: Anonymous Credentials for Onion Service DoS Resilience

NEEDS-REVISION proposals: ideas that we can't implement as-is

These proposals have some promise, but we can't implement them without certain changes.

• 212-using-old-consensus.txt: Increase Acceptable Consensus Age
• 219-expanded-dns.txt: Support for full DNS and DNSSEC resolution in Tor
• 245-tap-out.txt: Deprecating and removing the TAP circuit extension protocol
• 248-removing-rsa-identities.txt: Remove all RSA identity keys
• 269-hybrid-handshake.txt: Transitionally secure hybrid handshakes
• 279-naming-layer-api.txt: A Name System API for Tor Onion Services
• 291-two-guard-nodes.txt: The move to two guard nodes
• 317-secure-dns-name-resolution.txt: Improve security aspects of DNS name resolution

NEEDS-RESEARCH proposals: blocking on research

These proposals are interesting ideas, but there's more research that would need to happen before we can know whether to implement them or not, or to fill in certain details.

(There are no proposals in this category)

Inactive proposals by status

CLOSED proposals: implemented and specified

These proposals have been implemented in some version of Tor, and the changes from the proposals have been merged into the specifications as necessary.

• 101-dir-voting.txt: Voting on the Tor Directory System
• 102-drop-opt.txt: Dropping "opt" from the directory format
• 103-multilevel-keys.txt: Splitting identity key from regularly used signing key
• 104-short-descriptors.txt: Long and Short Router Descriptors
• 105-handshake-revision.txt: Version negotiation for the Tor protocol
• 106-less-tls-constraint.txt: Checking fewer things during TLS handshakes
• 107-uptime-sanity-checking.txt: Uptime Sanity Checking
• 108-mtbf-based-stability.txt: Base "Stable" Flag on Mean Time Between Failures
• 109-no-sharing-ips.txt: No more than one server per IP address
• 110-avoid-infinite-circuits.txt: Avoiding infinite length circuits
• 111-local-traffic-priority.txt: Prioritizing local traffic over relayed traffic
• 114-distributed-storage.txt: Distributed Storage for Tor Hidden Service Descriptors
• 117-ipv6-exits.txt: IPv6 exits
• 119-controlport-auth.txt: New PROTOCOLINFO command for controllers
• 121-hidden-service-authentication.txt: Hidden Service Authentication
• 122-unnamed-flag.txt: Network status entries need a new Unnamed flag
• 123-autonaming.txt: Naming authorities automatically create bindings
• 125-bridges.txt: Behavior for bridge users, bridge relays, and bridge authorities
• 126-geoip-reporting.txt: Getting GeoIP data and publishing usage summaries
• 129-reject-plaintext-ports.txt: Block Insecure Protocols by Default
• 130-v2-conn-protocol.txt: Version 2 Tor connection protocol
• 135-private-tor-networks.txt: Simplify Configuration of Private Tor Networks
• 136-legacy-keys.txt: Mass authority migration with legacy keys
• 137-bootstrap-phases.txt: Keep controllers informed as Tor bootstraps
• 138-remove-down-routers-from-consensus.txt: Remove routers that are not Running from consensus documents
• 139-conditional-consensus-download.txt: Download consensus documents only when it will be trusted
• 140-consensus-diffs.txt: Provide diffs between consensuses
• 148-uniform-client-end-reason.txt: Stream end reasons from the client side should be uniform
• 150-exclude-exit-nodes.txt: Exclude Exit Nodes from a circuit
• 151-path-selection-improvements.txt: Improving Tor Path Selection
• 152-single-hop-circuits.txt: Optionally allow exit from single-hop circuits
• 155-four-hidden-service-improvements.txt: Four Improvements of Hidden Service Performance
• 157-specific-cert-download.txt: Make certificate downloads specific
• 158-microdescriptors.txt: Clients download consensus + microdescriptors
• 161-computing-bandwidth-adjustments.txt: Computing Bandwidth Adjustments
• 162-consensus-flavors.txt: Publish the consensus in multiple flavors
• 166-statistics-extra-info-docs.txt: Including Network Statistics in Extra-Info Documents
• 167-params-in-consensus.txt: Vote on network parameters in consensus
• 171-separate-streams.txt: Separate streams across circuits by connection metadata
• 174-optimistic-data-server.txt: Optimistic Data for Tor: Server Side
• 176-revising-handshake.txt: Proposed version-3 link handshake for Tor
• 178-param-voting.txt: Require majority of authorities to vote for consensus parameters
• 179-TLS-cert-and-parameter-normalization.txt: TLS certificate and parameter normalization
• 180-pluggable-transport.txt: Pluggable transports for circumvention
• 181-optimistic-data-client.txt: Optimistic Data for Tor: Client Side
• 183-refillintervals.txt: Refill Intervals
• 184-v3-link-protocol.txt: Miscellaneous changes for a v3 Tor link protocol
• 186-multiple-orports.txt: Multiple addresses for one OR or bridge
• 187-allow-client-auth.txt: Reserve a cell type to allow client authorization
• 193-safe-cookie-authentication.txt: Safe cookie authentication for Tor controllers
• 196-transport-control-ports.txt: Extended ORPort and TransportControlPort
• 198-restore-clienthello-semantics.txt: Restore semantics of TLS ClientHello
• 200-new-create-and-extend-cells.txt: Adding new, extensible CREATE, EXTEND, and related cells
• 204-hidserv-subdomains.txt: Subdomain support for Hidden Service addresses
• 205-local-dnscache.txt: Remove global client-side DNS caching
• 206-directory-sources.txt: Preconfigured directory sources for bootstrapping
• 207-directory-guards.txt: Directory guards
• 208-ipv6-exits-redux.txt: IPv6 Exits Redux
• 214-longer-circids.txt: Allow 4-byte circuit IDs in a new link protocol
• 215-update-min-consensus-ver.txt: Let the minimum consensus method change with time
• 216-ntor-handshake.txt: Improved circuit-creation key exchange
• 217-ext-orport-auth.txt: Tor Extended ORPort Authentication
• 218-usage-controller-events.txt: Controller events to better understand connection/circuit usage
• 220-ecc-id-keys.txt: Migrate server identity keys to Ed25519
• 221-stop-using-create-fast.txt: Stop using CREATE_FAST
• 222-remove-client-timestamps.txt: Stop sending client timestamps
• 224-rend-spec-ng.txt: Next-Generation Hidden Services in Tor
• 227-vote-on-package-fingerprints.txt: Include package fingerprints in consensus documents
• 228-cross-certification-onionkeys.txt: Cross-certifying identity keys with onion keys
• 235-kill-named-flag.txt: Stop assigning (and eventually supporting) the Named flag
• 236-single-guard-node.txt: The move to a single guard node
• 237-directory-servers-for-all.txt: All relays are directory servers
• 238-hs-relay-stats.txt: Better hidden service stats from Tor relays
• 243-hsdir-flag-need-stable.txt: Give out HSDir flag only to relays with Stable flag
• 244-use-rfc5705-for-tls-binding.txt: Use RFC5705 Key Exporting in our AUTHENTICATE calls
• 250-commit-reveal-consensus.txt: Random Number Generation During Tor Voting
• 251-netflow-padding.txt: Padding for netflow record resolution reduction
• 254-padding-negotiation.txt: Padding Negotiation
• 264-subprotocol-versions.txt: Putting version numbers on the Tor subprotocols
• 271-another-guard-selection.txt: Another algorithm for guard selection
• 272-valid-and-running-by-default.txt: Listed routers should be Valid, Running, and treated as such
• 274-rotate-onion-keys-less.txt: Rotate onion keys less frequently
• 278-directory-compression-scheme-negotiation.txt: Directory Compression Scheme Negotiation
• 283-ipv6-in-micro-consensus.txt: Move IPv6 ORPorts from microdescriptors to the microdesc consensus
• 284-hsv3-control-port.txt: Hidden Service v3 Control Port
• 289-authenticated-sendmes.txt: Authenticating sendme cells to mitigate bandwidth attacks
• 293-know-when-to-publish.txt: Other ways for relays to know when to publish
• 297-safer-protover-shutdowns.txt: Relaxing the protover-based shutdown rules
• 298-canonical-families.txt: Putting family lines in canonical form
• 302-padding-machines-for-onion-clients.txt: Hiding onion service clients using padding
• 304-socks5-extending-hs-error-codes.txt: Extending SOCKS5 Onion Service Error Codes
• 305-establish-intro-dos-defense-extention.txt: ESTABLISH_INTRO Cell DoS Defense Extension
• 318-limit-protovers.md: Limit protover values to 0-63
• 328-relay-overload-report.md: Make Relays Report When They Are Overloaded

RESERVE proposals: saving for later

These proposals aren't anything we plan to implement soon, but for one reason or another we think they might be a good idea in the future. We're keeping them around as a reference in case we someday confront the problems that they try to solve.

• 133-unreachable-ors.txt: Incorporate Unreachable ORs into the Tor Network
• 172-circ-getinfo-option.txt: GETINFO controller option for circuit information
• 177-flag-abstention.txt: Abstaining from votes on individual flags
• 188-bridge-guards.txt: Bridge Guards and other anti-enumeration defenses
• 201-bridge-v3-reqs-stats.txt: Make bridges report statistics on daily v3 network status requests
• 211-mapaddress-tor-status.txt: Internal Mapaddress for Tor Configuration Testing
• 223-ace-handshake.txt: Ace: Improved circuit-creation key exchange
• 226-bridgedb-database-improvements.txt: "Scalability and Stability Improvements to BridgeDB: Switching to a Distributed Database System and RDBMS"
• 242-better-families.txt: Better performance and usability for the MyFamily option
• 255-hs-load-balancing.txt: Controller features to allow for load-balancing hidden services
• 256-key-revocation.txt: Key revocation for relays and authorities
• 262-rekey-circuits.txt: Re-keying live circuits with new cryptographic material
• 281-bulk-md-download.txt: Downloading microdescriptors in bulk
• 307-onionbalance-v3.txt: Onion Balance Support for Onion Service v3

SUPERSEDED proposals: replaced by something else

These proposals were obsoleted by a later proposal before they were implemented.

• 112-bring-back-pathlencoinweight.txt: Bring Back Pathlen Coin Weight
• 113-fast-authority-interface.txt: Simplifying directory authority administration
• 118-multiple-orports.txt: Advertising multiple ORPorts at once
• 124-tls-certificates.txt: Blocking resistant TLS certificate usage
• 143-distributed-storage-improvements.txt: Improvements of Distributed Storage for Tor Hidden Service Descriptors
• 145-newguard-flag.txt: Separate "suitable as a guard" from "suitable as a new guard"
• 146-long-term-stability.txt: Add new flag to reflect long-term stability
• 149-using-netinfo-data.txt: Using data from NETINFO cells
• 153-automatic-software-update-protocol.txt: Automatic software update protocol
• 154-automatic-updates.txt: Automatic Software Update Protocol
• 156-tracking-blocked-ports.txt: Tracking blocked ports on the client side
• 163-detecting-clients.txt: Detecting whether a connection comes from a client
• 169-eliminating-renegotiation.txt: Eliminate TLS renegotiation for the Tor connection handshake
• 170-user-path-config.txt: Configuration options regarding circuit building
• 185-dir-without-dirport.txt: Directory caches without DirPort
• 194-mnemonic-urls.txt: Mnemonic .onion URLs
• 210-faster-headless-consensus-bootstrap.txt: Faster Headless Consensus Bootstrapping
• 225-strawman-shared-rand.txt: Strawman proposal: commit-and-reveal shared rng
• 247-hs-guard-discovery.txt: Defending Against Guard Discovery Attacks using Vanguards
• 249-large-create-cells.txt: Allow CREATE cells with >505 bytes of handshake data
• 252-single-onion.txt: Single Onion Services
• 266-removing-current-obsolete-clients.txt: Removing current obsolete clients from the Tor network
• 280-privcount-in-tor.txt: Privacy-Preserving Statistics with Privcount in Tor
• 299-ip-failure-count.txt: Preferring IPv4 or IPv6 based on IP Version Failure Count

DEAD, REJECTED, OBSOLETE proposals: not in our plans

These proposals are not on-track for discussion or implementation. Either discussion has stalled out (the proposal is DEAD), the proposal has been considered and not adopted (the proposal is REJECTED), or the proposal addresses an issue or a solution that is no longer relevant (the proposal is OBSOLETE).

• 100-tor-spec-udp.txt: Tor Unreliable Datagram Extension Proposal [DEAD]
• 115-two-hop-paths.txt: Two Hop Paths [DEAD]
• 116-two-hop-paths-from-guard.txt: Two hop paths from entry guards [DEAD]
• 120-shutdown-descriptors.txt: Shutdown descriptors when Tor servers stop [DEAD]
• 127-dirport-mirrors-downloads.txt: Relaying dirport requests to Tor download site / website [OBSOLETE]
• 128-bridge-families.txt: Families of private bridges [DEAD]
• 131-verify-tor-usage.txt: Help users to verify they are using Tor [OBSOLETE]
• 132-browser-check-tor-service.txt: A Tor Web Service For Verifying Correct Browser Configuration [OBSOLETE]
• 134-robust-voting.txt: More robust consensus voting with diverse authority sets [REJECTED]
• 141-jit-sd-downloads.txt: Download server descriptors on demand [OBSOLETE]
• 142-combine-intro-and-rend-points.txt: Combine Introduction and Rendezvous Points [DEAD]
• 144-enforce-distinct-providers.txt: Increase the diversity of circuits by detecting nodes belonging the same provider [OBSOLETE]
• 147-prevoting-opinions.txt: Eliminate the need for v2 directories in generating v3 directories [REJECTED]
• 164-reporting-server-status.txt: Reporting the status of server votes [OBSOLETE]
• 165-simple-robust-voting.txt: Easy migration for voting authority sets [REJECTED]
• 168-reduce-circwindow.txt: Reduce default circuit window [REJECTED]
• 173-getinfo-option-expansion.txt: GETINFO Option Expansion [OBSOLETE]
• 175-automatic-node-promotion.txt: Automatically promoting Tor clients to nodes [REJECTED]
• 182-creditbucket.txt: Credit Bucket [OBSOLETE]
• 189-authorize-cell.txt: AUTHORIZE and AUTHORIZED cells [OBSOLETE]
• 190-shared-secret-bridge-authorization.txt: Bridge Client Authorization Based on a Shared Secret [OBSOLETE]
• 191-mitm-bridge-detection-resistance.txt: Bridge Detection Resistance against MITM-capable Adversaries [OBSOLETE]
• 192-store-bridge-information.txt: Automatically retrieve and store information about bridges [OBSOLETE]
• 195-TLS-normalization-for-024.txt: TLS certificate normalization for Tor 0.2.4.x [DEAD]
• 197-postmessage-ipc.txt: Message-based Inter-Controller IPC Channel [REJECTED]
• 199-bridgefinder-integration.txt: Integration of BridgeFinder and BridgeFinderHelper [OBSOLETE]
• 203-https-frontend.txt: Avoiding censorship by impersonating an HTTPS server [OBSOLETE]
• 209-path-bias-tuning.txt: Tuning the Parameters for the Path Bias Defense [OBSOLETE]
• 213-remove-stream-sendmes.txt: Remove stream-level sendmes from the design [DEAD]
• 229-further-socks5-extensions.txt: Further SOCKS5 extensions [REJECTED]
• 230-rsa1024-relay-id-migration.txt: How to change RSA1024 relay identity keys [OBSOLETE]
• 231-migrate-authority-rsa1024-ids.txt: Migrating authority RSA1024 identity keys [OBSOLETE]
• 233-quicken-tor2web-mode.txt: Making Tor2Web mode faster [REJECTED]
• 234-remittance-addresses.txt: Adding remittance field to directory specification [REJECTED]
• 241-suspicious-guard-turnover.txt: Resisting guard-turnover attacks [REJECTED]
• 246-merge-hsdir-and-intro.txt: Merging Hidden Service Directories and Introduction Points [REJECTED]
• 253-oob-hmac.txt: Out of Band Circuit HMACs [DEAD]
• 258-dirauth-dos.txt: Denial-of-service resistance for directory authorities [DEAD]
• 259-guard-selection.txt: New Guard Selection Behaviour [OBSOLETE]
• 261-aez-crypto.txt: AEZ for relay cryptography [OBSOLETE]
• 263-ntru-for-pq-handshake.txt: Request to change key exchange protocol for handshake v1.2 [OBSOLETE]
• 268-guard-selection.txt: New Guard Selection Behaviour [OBSOLETE]
• 270-newhope-hybrid-handshake.txt: RebelAlliance: A Post-Quantum Secure Hybrid Handshake Based on NewHope [OBSOLETE]
• 276-lower-bw-granularity.txt: Report bandwidth with lower granularity in consensus documents [DEAD]
• 286-hibernation-api.txt: Controller APIs for hibernation access on mobile [REJECTED]
• 320-tap-out-again.md: Removing TAP usage from v2 onion services [REJECTED]