commit 76b26c5dd46a633136e9d811125d91049b1b40a8 Author: George Kadianakis desnacked@riseup.net Date: Mon Apr 4 12:50:59 2016 +0300

prop224: Remove the MAINT_INTRO feature.

Too complex and not sufficient gain. For full rationale, please see thread: https://lists.torproject.org/pipermail/tor-dev/2016-March/010560.html --- proposals/224-rend-spec-ng.txt | 79 +----------------------------------------- 1 file changed, 1 insertion(+), 78 deletions(-)

diff --git a/proposals/224-rend-spec-ng.txt b/proposals/224-rend-spec-ng.txt index b3a567c..833224b 100644 --- a/proposals/224-rend-spec-ng.txt +++ b/proposals/224-rend-spec-ng.txt @@ -1088,11 +1088,6 @@ Status: Draft [00, 01] -- Reserved for legacy introduction cells; see [LEGACY_EST_INTRO below] [02] -- Ed25519; SHA3-256. - [FF] -- Reserved for maintenance messages on existing - circuits; see MAINT_INTRO below. - - [TODO: Should this just be a new relay cell type? - Matthew and George think so.]

The AUTH_KEY_LEN field determines the length of the AUTH_KEY field. The AUTH_KEY field contains the public introduction point @@ -1163,71 +1158,6 @@ Status: Draft authentication keys. Newer hidden services MAY use RSA keys up 1904 bits. Any more than that will not fit in a RELAY cell payload.

-3.1.3. Managing introduction circuits [MAINT_INTRO] - - If the first byte of an ESTABLISH_INTRO cell is [FF], the cell's body - contains an administrative command for the circuit. The format of - such a command is: - - Any number of times: - SUBCOMMAND_TYPE [2 bytes] - SUBCOMMAND_LEN [2 bytes] - SUBCOMMAND [COMMAND_LEN bytes] - - Recognized SUBCOMMAND_TYPE values are: - - [00 01] -- update encryption keys - - [TODO: Matthew says, "This can be used to fork an intro point to - balance traffic over multiple hidden service servers while - maintaining the criteria for a valid ESTABLISH_INTRO - cell. -MF". Investigate.] - - Unrecognized SUBCOMMAND_TYPE values should be ignored. - -3.1.3.1. Updating encryption keys (subcommand 0001) [UPDATE-KEYS-SUBCMD] - - Hidden service hosts send this subcommand to set their initial - encryption keys or update the configured public encryption keys - associated with this circuit. This message must be sent after - establishing an introduction point, before the circuit can be - advertised. These keys are given in the form: - - NUMKEYS [1 byte] - NUMKEYS times: - KEYTYPE [1 byte] - KEY [depends on KEYTYPE] - COUNTER [4 bytes] - SIGLEN [1 byte] - SIGNATURE [SIGLEN bytes.] - - The COUNTER field is a monotonically increasing value across a given - introduction point authentication key. - - The SIGNATURE must be generated with the introduction point - authentication key, and must cover the entire subcommand body, - prefixed with the string "Tor hidden service introduction encryption - keys v1". - - [TODO: Nothing is done here to prove ownership of the encryption - keys. Does that matter?] - - [TODO: The point here is to allow encryption keys to change while - maintaining an introduction point and not forcing a client to - download a new descriptor. I'm not sure if that's worth it. It makes - clients who have seen a key before distinguishable from ones who have - not.] - - [Matthew says: "Repeat-client over long periods of time will always - be distinguishable. It may be better to simply expire intro points - than try to preserve forward-secrecy, though". Must find out what he - meant.] - - Setting the encryption keys for a given circuit replaces the previous - keys for that circuit. Clients who attempt to connect using the old - key receive an INTRO_ACK cell with error code [00 02] as described in - section [INTRO_ACK] below. - 3.1.4. Acknowledging establishment of introduction point [INTRO_ESTABLISHED]

After setting up an introduction circuit, the introduction point reports its @@ -1301,6 +1231,7 @@ Status: Draft 3.2.2. INTRODUCE_ACK cell format. [INTRO_ACK]

An INTRODUCE_ACK cell has the following fields: + STATUS [2 bytes] N_EXTENSIONS [1 bytes] N_EXTENSIONS times: @@ -1314,14 +1245,6 @@ Status: Draft [00 02] -- Failure: key ID not recognized [00 03] -- Bad message format

- Recognized extension field types: - [00 01] -- signed set of encryption keys - - The extension field type 0001 is a signed set of encryption keys; its - body matches the body of the key update command in - [UPDATE-KEYS-CMD]. Whenever sending status [00 02], the introduction - point MUST send this extension field. - 3.2.3. Legacy formats [LEGACY-INTRODUCE1]

If a hidden service has listed a legacy introduction point in its